Industrial Chiller Repair Service

Engineer next to industrial chiller carrying out repair service to compressor

Industrial Chiller Repair Service

An industrial chiller repair service had been arranged to replace one of the compressors on System 1. Read on for a detailed insight into how we do things here at Maximus Chillers…

News Article No.28

During the last maintenance visit, the engineer in the photo had noticed all 3 of the 200 amp centred tag fuses had blown for one of the compressors. On investigation he found that there was a dead short to earth from the compressor windings. A Quote was submitted, an Order raised, then this was the return visit to carry out the job…

Decant during Industrial Chiller Repair Service

The refrigerant had to be decanted into the cylinder in the photo because the discharge shut off valve was passing. Once this operation had been carried out, the refrigerant cylinder was taken to the segregated storage area.

Oil Removal during Industrial Chiller Repair Service

Our engineer set up a drum for the recycling of the oil which was above the level of the oil equalizing pipe sight glass. He then used his equipment to remove the oil.

Compressor Removal during Industrial Chiller Repair Service

Electrical Wiring

The compressor motor connectors, the crank case heater and the motor protection module were disconnected. They were the put to one side to leave the compressor area clear.

Pipework

The discharge and the suction pipes were cut using our specialist tools which are carried in each vehicle. They were cut in a way so as to enable the easy lift out of the compressor.

Mounting Bolts

The compressor mounting bolts were then removed and set aside. The compressor was then ready for the lifting operation...

Lift and Shift

The yellow barrier in the photo was removed and set aside by the onsite engineers. Then, specialist lifting equipment was moved into place next to the compressor. ‘D’ shackles were used to attach to the lifting lugs on the compressor, then a sling was fitted between the ‘D’ shackles. The compressor was lifted out and taken to the metal recycling area. 

0161 370 7193

service@maximuschillers.com

Contact Form

A trainee moving a refrigerant cylinder during industrial chiller repair service
Training the next generation of chiller engineers

Compressor Refit during Industrial Chiller Repair Service

Now the reverse of the above: the new compressor was lifted into place and bolted down. Then, the oil equalising pipe was refitted.

Brazing

The permit to work was completed to allow for hot works and our copy of the paperwork was placed into a wallet on the side of the chiller.

Equipment Set Up and Health and Safety

The oxygen and acetylene cylinders were secured in an upright position in a location that was not in the way of an escape route. It was unlikely that there would be a safety incident because our equipment is of the highest quality, the best training is provided and our Risk Assessment Method Statement was adhered to. All of these things, taken together, are the reasons why an incident was unlikely. The regulators, flash back arresters, hoses and torch were then fitted and leak tested.

Pipework Preparation

Every time we carry out a brazing operation, we clean up the pipework so that it is as good as new. We remove all of the solder that remains on the pipework too. This is because leaks can occur around the compressor due to impurities getting into the soldering. The likelihood of leaks is compounded by the high pressures, temperatures and vibration of the compressor. We are succeeding at developing our brand of quality of service, so all of our workmanship is covered by a full, no quibble guarantee.

Light Up and Braze In

Our engineer lit the torch up and commenced the brazing operation. One of the brazes in particular was in an awkward location behind the compressor, so he started with that one first. Having completed the brazing operation, it was time to move on to the next phase of the job…

Oil Change during Industrial Chiller Repair Service

The correct grade of refrigeration oil, suitable for that compressor and the application had been sourced prior to the job. Our engineer then used his specialist equipment to charge the compressor sumps to the required level.

Pressure Test

A nitrogen pressure test was the carried out which was witnessed at the start and at the end by the customer. The pressure test certificate was then completed which was filed in the customers’ F-gas register.

0161 370 7193

service@maximuschillers.com

Contact Form

Dehydration during Industrial Chiller Repair Service

Each of our mobile workshops carries a powerful 10cfm vacuum pump which speeded up the dehydration process.

Non Condensables

The vacuum pump also removed the non condensables: air and nitrogen which had got into the system during the compressor swap out.

Torr Gauge

A torr gauge was connected to the chiller at the appropriate location which read the last 40 Torr of the atmosphere.

Hoses

Hoses were then connected to the vacuum pump to start the dehydration process.

Deep Vacuum

A vacuum of 2 Torr was achieved which ensured that the moisture in the system was removed along with the non condensables.

Refrigerant Recharge

The refrigerant used for this particular chiller was R410a. This was then charged into the system according to standard industry guidelines.

Testing during Industrial Chiller Repair Service

There was sufficient load available for the test run of the chiller. This was because this system had been shut down during the service visit, which had caused the other system to compensate by loading up.

Superheat and Subcooling

Test equipment was fitted to the chiller and the superheat and subcooling values were taken. There was a high superheat value at first, so more refrigerant was charged into the system until standard industry guidelines were achieved.

Oil Return and Compressor Temperatures

Good oil return was recorded and the various temperatures were taken around the compressor. All readings were found to be nominal and the chiller went back into seamless operation.

Related Articles:
Scroll Chiller Compressor Maintenance

F-gas Chiller Leak Testing

Chiller Failure

Hit the Tags at the top of the page to navigate your way to our extensive library of further reading on this subject.

Read more about Oxy-Acetylene Torch Flame Brazing at School Work Helper.


Process chiller repair service being carried out on evaporator and expansion valve

Process Chiller Repair Service

We at Maximus Chillers have just carried out a process chiller repair service for a customer of ours in the North West. The expansion valve on System 1 had been found to have failed and this was the return visit to rectify. There is N+1 redundancy built into the plant, so there was not an immediate hurry to attend site. When our engineer diagnosed the fault, he had a look in our customer’s stores as he knows our customer likes to keep spares. Sure enough- there was a spare expansion valve on the shelf, so he took it and put it in the chiller panel ready for the job.

News Article No.27

Process Chiller Repair Service to Jammed Valve

What had happened to the old expansion valve was that the mechanical part had worn down and jammed part open. This meant that the refrigerant circuit would run for a while with a poor superheat reading, but would trip out on low pressure when more scroll compressors started running.

Isolate Electricity

Our engineer disabled System 1 and removed the fuses. This was to prevent an accidental start up during the repairs. He used his lock off padlock, to which, he was the only engineer with a key.

Refrigerant Decant

The full refrigerant charge was recovered into 2 small recovery cylinders which were taken to the refrigerant storage cage. This is a segregated area to reduce the risk of explosion in the event of a fire. It is also shielded from direct sunlight to reduce refrigerant pressure inside the cylinders.

Hot Works Permit during Process Chiller Repair Service

The next stage of the job was to remove the failed expansion valve, so a Hot Works Permit needed to be obtained from the Maintenance Department. It was counter signed by the permit issuer and our engineer with the fire watch time added to the additional information section.

0161 370 7193

service@maximuschillers.com

Contact Form

Oxy-acetylene

The equipment was taken out of the company vehicle and set up near to the chiller. Care was taken to ensure that the oxy-acetylene was not in the escape route for our engineer in the event of an accident. The condition of the equipment was inspected and a leak test carried out.

Strip Down during Process Chiller Repair Service

The covers were removed from the location of the expansion valve, the lagging stripped back and the electrical connection removed. The old expansion valve was now ready for removal…

Remove and Replace

Our engineer heated the inlet to the valve until the solder melted and then removed the liquid pipe. He then repeated this on the expansion pipe. Now that the old valve had been removed, he used a specialist tool to clean off the remaining solder and impurities on the refrigerant pipework. Having done this, he fitted the new valve into position. A special heat sink was used to protect the new expansion valve during the brazing operation. Then, the inlet and the outlet pipes were silver soldered into position.

Pressure Testing during Process Chiller Repair Service

The integrity of the entire system was proven by carrying out a nitrogen pressure test according to standard industry guidelines. The customer witnessed the start and the finish of the test and this was recorded on the Pressure Test Certificate.

Dehydration Process during Process Chiller Repair Service

Our engineers carry a powerful 10 cfm vacuum pump as part of the equipment in his car. This pump speeds up the removal of moisture and also non condensables from the system such as air and nitrogen. Our engineer left the process running overnight and returned in the morning to find deep vacuum had been achieved.

Refrigerant Recharge

The correct amount of refrigerant was recharged into the system and the cylinders were returned to the storage area.

0161 370 7193

service@maximuschillers.com

Contact Form

System Testing

The controller of this machine automatically gives you the fridge system readings. However, our engineer wanted to fit his own test equipment to the chiller anyway. This was to test that both readings were the same for calibration purposes. Having done this, he ran the system and waited for it to load up to 100%. Then, he took the superheat and the subcooling readings which were found to be within standard industry guidelines.

Clear Site

All of our engineers leave the work location of the chiller in a better condition than before they attended site. Good house husbandry goes a long way to promote the professionalism of a chiller company. The little things are what you, the customer, often notice first as some of the more technical things are not always so obvious.

Paperwork Sign Off

The permit to work was signed off having completed a satisfactory fire watch. Our paperwork was then completed and scanned into Head Office. We like to do this on the day of the job, so your accounts department gets the report promptly and can start processing the Invoice.

Monitoring

Our engineer then gave the chiller a mini service for the rest of the day. All readings were taken on both of the refrigerant systems and compared to the Tick Sheet of the previous maintenance visit. This was to see if there was a deterioration of any of the readings over a period of time. Small problems would show up before they turned into big problems. This is just another way of how we at Maximus Chillers saves you money.

Courtesy Visit

Just to make sure that the machine had settled down satisfactorily and that there were no further issues- our office arranged a courtesy visit a few days later. The chiller system was still operating as it should and there were no other faults to report.

Related Articles:
Chilled Water System EEV Service

How do Chillers Work? Expansion Valves

F-gas Chiller Leak Testing

Hit the Tags at the top of the page to navigate your way to our extensive library of further reading on this subject.

Read more about electronic expansion valves on the Carel website.


New fan decks being lifted onto ammonia chiller during chiller repair service

Chiller Repair Service

An effective chiller repair service is what you need to get you up and running- fast! Here at Maximus Chillers, no job is too small, or too big. We have the capability to do anything from replacing contactors to centrifugal compressor remanufacturing- we are a one stop shop for all of your needs.

News Article No.26

Customer Orientated Chiller Repair Service

We also know the reason why we are an expanding company: you- the customer! Listening to your requirements goes a long way to help us achieve your objectives. We assign the same engineer to each site, so that you have the chance to build up a relationship and he gets to know your plant. Read on for an insight into some of the repairs that we carry out…

All new fan decks in place on large air cooled chiller during chiller repair service
Fast supply chain for retrofitting fans

Fan Deck Retrofitting Chiller Repair Service

The photos show the fans being lifted up, then when they are in position on a 200kw ammonia chiller. The fans had been failing one at a time until the chiller started experiencing high pressure trip outs. Action was not immediately taken because there were insufficient funds in the customer’s budget. When the customer was allocated a new budget, they gave us the Order to carry out the work. We decided to change all 8 fans.

Odd Size

The old fans were 790mm blade diameter instead of the standard 800mm. Manufacturers ask suppliers for odd sizes and specifications along with an OEM data plate in an attempt to monopolise the customer. A bonafide chiller company, however, is adept at making square pegs fit round holes. Not really a round hole though with this one- we just plonked our fan decks on top where the old ones had been fitted.

0161 370 7193

service@maximuschillers.com

Contact Form

Refrigerant Leak Chiller Repair Service

HFC refrigerants are becoming more expensive due to the HFC phase down. Therefore, as well as the environmental cost of a leaking chiller, there is the cost on your pocket too. At Maximus Chillers we find the root cause of the leak instead of just brazing it up. Some of these causes are:

Condenser Vibration

Some head pressure control systems bring the fans on, forwards and backwards in different stages. This causes the chiller frame to judder and vibration related leaks to occur on the condenser. The solution is easy- fit stand alone fan speed controllers.

Compressor Vibration

Some chillers are designed to fit into a small footprint of space. A good example of this is a particular model of laser chiller that had been designed to fit down the side of a laser cutter. That’s alright until, years after production, reoccurring leaks start happening around the compressor. There is no room to fit vibration eliminators, besides, they only work if they are fitted horizontally and vertically with the far end being clamped. Brazing the leak up just causes the already work hardened copper pipe to further anneal and become even more brittle- another leak will happen shortly there after. The solution is to remove the whole piece of pipework, go up a pipe size and replace it with new.

Component Failure

We find some components are flawed and are prone to leaking. An example of this are refrigerant hoses which are prone to rubbing through against the chiller. The solution is to fit anacondas or static copper pipework.

Reduced Service Costs

All of these measures and more are how we reduce the frequency of refrigerant leaks on your plant.

0161 370 7193

service@maximuschillers.com

Contact Form

Compressor Remanufacturing Chiller Repair Service

Weather you have scroll, reciprocating, screw or centrifugal compressors, we have the capability to get it out, rebuild it and get it back in again. With same day delivery of internal compressor components- we won’t keep you waiting around. Our expert team are adept at ensuring that your compressors are rebuilt with minimal run out and have clearances that are within tolerance. All bolts are touqued up to the correct setting too. The last part of the job is the compressor paint re spray to the same colour as before, or to our standard battleship grey.

Controls Retrofitting Chiller Repair Service

When a controller fails it is often found to be obsolete. Don’t worry because we can fit a new controller to any machine. For HFC chillers we fit Carel controllers, we fit Beijer Electronics to ammonia chillers and MCS controllers to centrifugal chillers.

Strip Out

The easiest way to do a controls retrofit is to start all over again from scratch. We remove the defunct controls from the panel and pull all the control wiring out too. We leave the three phase wiring in place, the contactors and the common neutral.

Rewire

One wire at a time, we rewire the chiller. All of the analogue inputs are wired in along with the digital inputs. Then, the outputs are wired to the contactors and relays. The transformers in the panel are often reused to get the various voltages that are required for the new controller, contactor coils and relay coils.

Commissioning

The new controllers come pre set with default parameters so only minor adjustments are needed to get the chiller to settle down. We then spend the rest of the day monitoring the chiller so as to watch it running in the various stages of loading and under different running conditions.

Chiller Repair Service that is Second to None

The above examples are just an insight into our extensive range of capabilities in the repairs of your plant. Basically- if you have a problem- then we have a solution. This is just part of what we call the MAXIMUS ADVANTAGE™ Any Chiller- Any Problem- Any Part- Any Refrigerant- Anywhere. With customers around the world in places like Saudi Arabia, Spain and the United States of Amarica we continue to exceed the expectations of our customers. We have a network of engineers around the UK too, so we are never farer than a couple of hours away. For the best service, the choice is clear- Maximus Chillers!

Related Articles:
Chiller Fan Deck Service

How do Chillers Work? Compressors

Chiller Controls Company

Hit the Tags at the top of the page to navigate your way to our extensive library of further reading on this subject.

Read more about refrigerant leak causes & tests at Herzing College.


Showing how do chillers work with pipework of black centrifugal compressor

How do Chillers Work? Compressors

How do chillers work, this time focusing on compressors. Read below and we will explore the subject in detail…

The compressor can be seen as the heart of a chiller system. As explained in the last article in our Chiller Basics series: it enables the principle of the pressure temperature relationship to take place and circulates the refrigerant.

Evaporator

The sucking action of the compressor drops the pressure in the evaporator. This lower pressure, corresponding to a lower temperature, enables the refrigerant to boil off, absorbing latent heat from the process. The refrigerant, laden with heat energy, is then sucked into the compressor.

Condenser

The refrigerant is discharged from the compressor at a high pressure, relative to a high temperature, this is sufficiently above atmospheric temperature to enable the latent heat in the refrigerant to exchange into the surrounding air.

How do Chillers Work - Mass Flow Rate of Compressors

Compressors enable the refrigerant to flow around the system. The higher the pressure of the refrigerant, the higher the mass and so the higher the mass flow rate. In low temperature systems that run on a vacuum, a very large compressor is needed to achieve the required mass flow rate and so to cool the process.

Below are the 4 main types of compressors and how they work…

0161 370 7193

service@maximuschillers.com

Contact Form

How do Chillers Work - Scroll Compressors

This compressor is more often found on smaller chillers. Scroll is another way of describing a spiral. There are two spirals, one inside the other. One of them is fixed and the other one orbits. This creates crescent shaped gaps in between the two spirals. The volume of these crescent shapes gets smaller towards the middle of the spirals and so compresses the refrigerant. The refrigerant is then discharged through a port at the middle of the scrolls.

Maintenance

Scroll compressors are meant to be maintenance free as they are hermetically sealed with no moving parts on the outside. However, the correct amount and sufficient quality of lubricating oil must be maintained to prolong its life. A lack of routine maintenance by a chiller company causes frequent compressor failures and also allows acid to accumulate in the system. This acid causes further compressor failures to occur. Give us a bell and we will put together a tailor made maintenance schedule to prolong the life of your plant.

How do Chillers Work - Reciprocating Compressors

Small

These compressors can be small and used for low capacity applications. The motor is usually inside the compressor with the cylinder heads being removable. This is described as being a semi hermetic compressor.

Large

Reciprocating compressors can also be very large and often arranged in multiple compressor systems for high capacity applications. They are open drive when used with ammonia refrigerant which means that the motor is external from the compressor. This is because ammonia corrodes the copper windings of the motor.

How They Work

The circular motion of the crankshaft is converted into the linear motion of the connecting rods and pistons running up and down inside the cylinders- see a video of how they work. Another way of describing back and forth linear motion is reciprocating. The refrigerant is sucked into the cylinder on the down stroke and then the suction inlet valves are closed. The trapped refrigerant is compressed on the up stroke and then the discharge valves are opened when the piston reaches the top of the cylinder.

Maintenance

Reciprocating compressors need regular maintenance and strip downs at pre prescribed intervals. Failure for this to be carried out results in internal components becoming worn or loose. This imbalance in the compressor causes further wear and damage to take place. Eventually something like a piston comes loose and a compressor smash up occurs. The damage is usually limited due a low oil pressure condition occurring from the location of where the part came loose. Sometimes, however, parts of the connecting rods stay attached to the crankshaft which flail around inside the compressor. An example of this is when a compressor we rebuilt had carried on running on the last one of its 8 cylinders. The rest of the internal compressor components were reduced to small, triangle shaped pieces of metal in the sump. Our maintenance saves money!

0161 370 7193

service@maximuschillers.com

Contact Form

How do Chillers Work - Screw Compressors

A pair of matched helical rotors are machined to a high tolerance. One of them is driven by a motor and the other one interlocks with it. The gap between the rotors gets smaller as the refrigerant continues down the screw and so compression is achieved. Oil is injected into the screw to provide a seal, to lubricate and to cool the rotors.

Maintenance

This type of compressor is very reliable and can quite often out live the chiller. The components around the screw, however, require regular maintenance and replacement to enable the compressor to function effectively. Some of these components include the loading solenoids and coils, also the slide valve and its potentiometer which senses its position. When these components are not working as they should, the compressor cannot match the required load and so excessive electricity consumption occurs. The inspection, adjustment and replacement of these components is another way of how our maintenance saves money.

How do Chillers Work - Centrifugal Compressors

These compressors are mostly found on very high capacity systems used for the cooling of large industrial processes, district cooling and the cooling of large facilities. The compressor in the photo, however, is a small centrifugal compressor used for the cooling of a building.

How They Work

The refrigerant is sucked into the middle of the impellor. Then, centrifugal force pushes it out to the tip of the impellor edge and so providing the compression. Unlike the compressors above, these compressors are not positive displacement and so they have a lower compression ratio. That is to say: a lower difference in pressure between the suction and the discharge.

Maintenance

Regular oil and filter changes are required to prolong the life of the bearings. When this kind of compressor fails due to worn bearings and damaged internal components, the rebuild is extremely expensive. Read more about our centrifugal compressor remanufacturing facility

Related Articles:
Scroll Chiller Compressor Maintenance

Reciprocating Chiller Compressor Maintenance

Screw Chiller Compressor Maintenance

Centrifugal Chiller Compressor Maintenance

How do Chillers Work? Expansion Valves

Chiller Repair Service

Hit the Tags at the top of the page to navigate your way to our extensive library of further reading on this subject.

Read more about types of compressors on the Carel website


6 green Bitzer scroll compressors being maintained in a chiller

Scroll Chiller Compressor Maintenance

Here at Maximus Chillers, we carry out scroll chiller compressor maintenance to extend the lifespan and reduce downtime to your critical plant. This planning ahead is central to how we do things- we resolve small problems before they become big problems. Having the capability to do anything is part of what we call the MAXIMUS ADVANTAGE™ Any Chiller- Any Problem- Any Part- Any Refrigerant- Anywhere.

How they Work

The refrigerant vapour passes in between two scrolls (spirals) One of these is fixed, the other orbits backwards and forwards against the fixed scroll using a swing link. This creates a series of crescent shaped gas pockets in between the scrolls. These gas pockets get smaller in size as the refrigerant travels from the suction at the edge, down the spirals to the discharge at the centre. It then leaves downwards through a port. There are check valves to prevent back feeding of refrigerant during off cycles when other compressors on the same system are still running.

Advantages

There are several gas pockets occurring at any one time through the scroll, therefore giving a smooth and continuous compression cycle. Other advantages are low internal friction resulting in a quiet operation and low vibration levels. These low vibration levels help to lower the occurrence of leaks around the compressor.

Oil Level during Scroll Chiller Compressor Maintenance

The correct oil level is noted on our detailed Tick Sheets for all of the compressors. This record helps with the diagnosis when things start to go wrong. We can look for a pattern where the level starts to drop off in the compressors on a particular system, then look at the other readings which may be the cause.

Oil Samples during Scroll Chiller Compressor Maintenance

At periodic intervals, we take oil samples which we analyse in our laboratory at Head Office in Droylsden. We look for white metal, coloured metal, refrigerant composition, acid and sludge. This means that we can notice, then resolve system issues before a costly compressor failure occurs.

Oil Changes during Scroll Chiller Compressor Maintenance

This kind of compressor is fitted with a service port for the draining and filling of oil. The correct procedure is followed due to system pressure being present inside. We then carry out the oil changes using our specialist oil handling tools. Our skilled engineers carry the correct PPE for the work being carried out. We also we provide Risk Assessment Method Statements for each job.

0161 370 7193

service@maximuschillers.com

Contact Form

Crank Case Heaters

In the photo you can see the silver band of the crank case heaters at the bottom of the compressors. They keep the oil at the required temperature so as to not cause compressor wear on start up. The heaters also have the effect of ensuring that the refrigerant cannot condense into liquid during cold weather. As a compressor cannot compress a liquid, compressor failure would occur. A normally closed contact on the delta compressor starter contactor usually runs the heater: it drops out when the compressor starts. The function of all of these heaters is checked on each maintenance visit.

Discharge Temperature

It is critical that the discharge temperature is not too high, as this is the cause of the refrigerant breaking down into acid and sludge as previously mentioned. The acid rots the insulation on the copper windings inside the compressor. When this has occurred, an electrical failure will result in the compressor, causing the fuses to blow and a fault condition on the chiller. Compressor swap out is the cure which is expensive and inconvenient. We take the discharge temperature readings during the maintenance so as to fault find the cause.

Suction Pressure

Adequate suction pressure is needed to ensure good oil return to the compressor and prevent low pressure trips. As the refrigerant entrains the oil around the system, a good mass flow rate is needed, or the oil will just ‘pool’ in the bottom of the evaporator. Poor oil return will result in a seized compressor. Therefore, particular attention is taken to the low pressure gauge by our engineers. System adjustments or recommendations are made to ensure the seamless operation of your plant. If system overhaul is required, a Quote will be submitted at the end of the visit.

0161 370 7193

service@maximuschillers.com

Contact Form

Compressor Holding Down Bolts

There are usually four of these on each compressor. They fit though a steel sleeve which, in turn, fits through a rubber mount. The whole assembly is bolted into the frame of the chiller. The function is to securely hold the compressor in place and to dissipate vibration. We check the tightness is correct with our torque wrenches and change the rubbers periodically. A compressor rattling around uncontrollably, especially during start up and stopping causes catastrophic leaks around the compressor. This usually leads to the whole, or the most part of the refrigerant charge being lost to atmosphere.

Motor Protection Module

A resistance sensor embedded in the compressor windings plugs into this module on the S1 and S2 terminals. The fault feedback to the controls is on the M1 and M2 terminals. The power supply to the module is on the L and N terminals. When the windings start to get hot, the module detects this after a pre determined level of resistance is reached. The M2 terminal opens and volts drop out to the relay board, then a lower volt control signal drops out to the controller. We check the sensor resistance and compare it to a chart to ensure it is within the allowable range on each visit.

Wire Tightening during Scroll Chiller Compressor Maintenance

We waggle the motor connectors and check for any cracking to the wires which may lead to an earth sort out. We tighten the wiring on the compressor starter contactors and check the condition of the contactor contacts. These become ‘splattered’ causing an uneven amount of amps to the compressor. This volt drop causes the contactors to fail and will eventually cause compressor motor failure. We change the contactor contacts from our range of parts at Head Office.

People also like this page:
Centrifugal Compressor Remanufacturing

Related Articles:
Chiller Parts Supplier

Chiller Compressors

Air Cooled Chiller Condenser Maintenance

Shell & Tube Evaporator Maintenance

Screw Chiller Compressor Maintenance

Chiller Controls

Centrifugal Chiller Compressor Maintenance

Chiller Condensers

Reciprocating Chiller Compressor Maintenance

Chiller Controls Company

Industrial Chiller Repair Service

To read more about scroll chiller compressors hit the Tag at the top of the page.

Read more about scroll compressors on Wikipedia


Large chiller, refrigerant cylinder, brazing equipment and tools during chiller service company visit

Chiller Service Company Visit

A typical rainy day in the North West, perfect for a chiller service company visit.

News Article No.11

Electrical Faults during Chiller Service Company Visit

This was a return visit to do a refrigerant leak, but the customer alerted our engineer’s attention to an electrical fault. System 2 was found to be locked out in fault on the recent maintenance visit, but now System 1 was being held off too. The fault message on the controller was High Pressure. The controller sends a 240v fault feedback signal, through the high pressure switch which returns to the controller. Our engineer had a look at the wiring diagram to find the number on the terminal strip and checked it out with his multimeter. As he suspected, there were volts going out, but not coming back. He removed the side panel for system 1 and found the switch on the discharge pipe. It was the type that has a red button on the top. When he pressed it, there was a click and volts returned to the controller.

Alarm Reset during Chiller Company Service Visit

He interrogated the Carel controller and followed the reset procedure. The controls went through a timer and then the start sequence was initiated.

Run Testing during Chiller Company Service Visit

After the first scroll compressor started, the head pressure started to build up, but the condenser fans did not start. The on board high pressure gauge carried on rising until the high pressure switch was tripped again.

Head Pressure Control

A transducer on the discharge is used by the controller to sense the pressure in the condenser. When our engineer looked for this in the controller, it was found to be reading wrong by a considerable amount. There is a facility to enter a password and recalibrate the transducer, but this only allows for a small adjustment.

Test Instrument

Our engineers carry various kinds of test instruments which can be used to give a temporary false reading to the controller. This gets the customer up and running and back in production whilst a new transducer is ordered and sent to site.

0161 370 7193

service@maximuschillers.com

Contact Form

Chiller Company Service Low Pressure Visit

Now on with the job to resolve the low pressure issue with the chiller.

Refrigerant Pump Out

Our engineer lifted the liquid line solenoid valve and decanted the remaining refrigerant into a vessel using his recovery unit. He only got out 7kg of a charge of 36kg.

Leak Testing during Chiller Company Service Visit

We use nitrogen for the leak testing as it is an inert gas that will not cause problems with the refrigerant system. There was a sign of the leak in between the steel frame at the middle of the condenser and the condenser tubes. We always strip the chiller down and leak test the entire system though. This is so that the job does not end up going round in circles. At first the leak could not be found, so the pressure was built up in stages, taking into account industry recommended guidelines for a chiller. Sure enough the leak was where it was suspected to be. The occurrence of this kind of leak can be reduced with the use of vibration eliminators.

Brazing during Chiller Company Service Visit

The location of the leak was reported to the maintenance engineer onsite and a hot work permit obtained. The equipment we use is tested at regular intervals to be safe and in good working order. A half hour fire watch was stipulated in the permit, along with the removal of combustible materials from the work location. Correct PPE being donned, he brazed the leak to the required industry standards.

F-gas Pressure Test

A chiller has a different pressure test procedure to other systems, so our engineer built the pressure up according to industry standards, then recorded it on his pressure test certificate. After the required time had elapsed, he rechecked the readings which were found to be satisfactory.

Vac Pump

Each of our engineers carries a state of the art 10 cfm vacuum pump to speed up the dehydration process. We use high quality Torr gauges too, so as to get an accurate pressure reading. A good read back was achieved at the end of the process.

Recharge and Run Test

After the refrigerant recharge was carried out, a satisfactory run test was achieved.

0161 370 7193

service@maximuschillers.com

Contact Form

Refrigerant Economizers

This particular chiller uses an economizer to further subcool the refrigerant. Chiller designers have worked out that the end user can save a considerable amount of money over 10 years if these components are used. After the subcooled liquid refrigerant leaves the condenser, it goes through a plate heat exchanger. Some of this refrigerant, however, is diverted through a thermostatic expansion valve, to the other side of this plate heat exchanger. Further subcooling occurring through the plates.

Expansion Valve

The refrigerant drops in pressure as it goes through the expansion valve. A bulb is fitted to the suction pipe on the outlet of the heat exchanger. The bulb has to be at the correct 'o clock position as oil insulation will affect the operation of the valve. A capillary tube connects the bulb to the valve. Inside the bulb, the same kind of refrigerant that is running in the system is present in its liquid state. As the temperature rises in the suction pipe, this refrigerant boils off, adding pressure into the capillary tube. This added pressure forces the power element down on the valve body and a needle forces the valve open.

Flash Gas

Imagine if the refrigerant was not subcooled at all. It would be around its saturation point with a lot of it flashing off into its vapour phase. Not good when you have warm water coming back from the process. The refrigerant would not absorb very much latent heat into the refrigerant system.

Efficiency

Imagine, on the other hand, the economizer which is fitted to this chiller. Now we have a good proportion of refrigerant in its liquid phase, on the low side of the system, with a minimum amount of flash gas. The warm process water has more chance to cool and the refrigerant absorbs a lot more latent heat. The chiller achieves set point easier and therefore saves a considerable amount of electricity. With this further subcooling monitored for a while, time for a signature from the customer and another job well done!

Related Articles:
Chilling Plant Service

Chilled Water System EEV Service

Water System Service of Evaporator

HFC Chiller Service

Process Chiller Vacuum Service

Chiller Breakdown

Chiller Fault Finding & Diagnosis

F-gas Chiller Leak Testing

Chiller Commissioning

Air Cooled Chiller Condenser Testing

Chiller Problems

To read more about chiller electrical faults hit the Tag at the top of the page.

Read more about F-gas leak checking at Refcom


400 kw white chillers with panels open during air cooled chiller maintenance

Air Cooled Chiller Maintenance

A nice day to carry out air cooled chiller maintenance at a new site we have taken over in the South East.

News Article No.6

Our engineer attended site at around 9am with the risk assessment method statement having been sent in advance. A site survey was carried out to see if there were any additional risks. Should there have been any changes- the RAMS have a section for the additional risks and control measures. After gaining a permit to work, our engineer was issued with a security pass to access the chiller compound. Three chillers are located in the compound which feed air handlers for a critical application. Two of the chillers are multiple system, scroll compressor, air cooled chillers. The other is a single system screw chiller.

Program Settings during Air Cooled Chiller Maintenance

A complete download of the program settings is available in our engineer’s phone. This is to cross reference the settings, should one of them be accidentally changed by the maintenance engineers. On site engineers are the first port of call for chiller trip outs, with the responsibility to get the plant up and running. We offer real time assistance, over the phone from our Technical Support Desk and can send user manuals in PDF form, direct to their computer. The settings were found to be nominal, so a detailed analysis of the alarm history was carried out:

Alarm History during Air Cooled Chiller Maintenance

In reverse date order, the alarm history of all the systems was interrogated. There had been several system shut downs to carry out the periodic maintenance by the onsite personnel. The electricity having been shut down, there was a subsequent oil pre heating timer in the history too. On Chiller 2, System 1 however, there had been several low pressure trip outs. Our engineer decided to start the maintenance with this system by carrying out a full diagnosis of the low side of the refrigerant system:

0161 370 7193

service@maximuschillers.com

Contact Form

Superheat during Air Cooled Chiller Maintenance

The system runs on R410a refrigerant. This refrigerant has higher operating pressures in comparison with other HFC refrigerants. It has an efficient temperature range which can be seen on a pressure enthalpy chart. Below or above this range- the refrigerant loses efficiency and so has a lower coefficient of performance. The most common saturation point for this refrigerant is 0°C which corresponds to a 7 bar suction pressure in the evaporator. Above this is the superheat of the refrigerant returning to the compressor. On this occasion there was found to be 26°C of superheat and a suction pressure of 4 bar- close to the low pressure trip out. After careful diagnosis, our engineer decided to focus his attention on the expansion valve:

Thermostatic Expansion Valve

There are 4 forces acting on a TEV:

Liquid line pressure coming from the condenser.
Versus
Suction pressure down the equalising line from the far side of the evaporator. This compensates for the pressure drop across the evaporator and shows the true compressor side pressure.

Spring pressure acting upwards and closing the valve.
Versus
Bulb pressure forcing the valve open.

To reduce the superheat, the bulb should have forced the valve open. The refrigerant charge in the bulb acts upon the bellows to achieve this. The reason for the malfunction, on this occasion, was found to be the failure of the expansion valve orifice. It had become jammed- causing a shortage of refrigerant in the evaporator and high superheat.

Latent Heat

Our engineer was carrying out the above fault finding with one compressor running and the other two being held off. This was to prevent a low pressure trip. Where chillers are left running with a high superheat condition, the reduced amount of latent heat causes a higher cost in electricity relative to refrigeration effect (COP) The refrigerant carries on superheating without absorbing latent heat- pointless and inefficient for a chiller.

Chiller Pump Down

For convenience, this chiller can be pumped down and valved off using the service valves. The evaporator can be worked on after breaking in procedures are carried out. Therefore, we have arranged for this to be carried out before fitting the new expansion valve parts. These chillers also have the ability to pump down the refrigerant on receiving a fault feedback from the electronic leak detector. This is an added measure to lower the environmental impact of refrigerant leaks.

0161 370 7193

service@maximuschillers.com

Contact Form

Subcooling during Air Cooled Chiller Maintenance

This is cooling the refrigerant vapour down, through the latent heat phase and then subcooling the liquid down further. On System 2 of the same chiller, a subcooling issue was identified. 21 bar/ 36°C saturation was normal for that system as defined by the fan speed controller. Now, the system pressure was higher at 28 bar/ 47°C saturation, so our engineer decided to work out the subcooling. A very high reading of subcooling was recorded at 28°C this was diagnosed to be due to non condensables in the refrigerant:

System Non Condensables

Non condensables are gases that will not condense, such as, air and nitrogen. If nitrogen is not vented properly and a deep vacuum then achieved, the gasses will remain in the refrigerant system. When calculating the subcooling, the readings work out incorrectly due the presence of the gasses. This can lead to false diagnosis. The remedy for the issue was to arrange a full refrigerant decant, pressure testing and dehydration, before charging with new refrigerant.

Efficiency

Having good subcooling values on a refrigerant system is critical to efficiency. Where there is no subcooling- the refrigerant has not fully rejected all the latent heat from the condenser. This can be seen when looking at a PH chart and plotting the pressures and temperatures. This heat remains in the refrigerant and adds to the system along with heat added from the compressor and heat from the process. This is another reason the coefficient of performance is reduced and so incurring increasing electricity costs for the plant.

Economizer

These chillers are also fitted with refrigerant economizers- one for each system. They work by diverting some of the refrigerant from the condenser, through a small expansion valve, then through a plate heat exchanger. The rest of the liquid refrigerant passes on the other side of the plate heat exchanger and so is further subcooled.

Related Articles:
Air Cooled Chiller Planned Maintenance

Water Chiller Maintenance

Process Chiller Maintenance Visit

Chilled Water System Maintenance

Centrifugal Chiller Maintenance

Industrial Chiller Maintenance

Air Cooled Chiller Condenser Maintenance

Glycol Chiller Maintenance

Chiller Maintenance Company

Chilling Plant Maintenance

Preventative Chiller Maintenance

To read more about chiller control systems hit the Tag at the top of the page.

Further reading on chilled water at Wikipedia


Chiller compressor failure of blue Grasso in enclosure

Chiller Compressors

System Testing for Chiller Compressors

Chiller compressors fail often as a result of ineffective servicing and system testing. At Maximus Chillers, we carry out extensive tests during our visits to ensure that small problems are resolved before they become big problems. If we notice a reading starting to become abnormal, we can carry out the diagnosis and then remedy the problem. Some of the compressor readings we monitor are:

Temperature of Chiller Compressors

The suction, discharge, motor windings and bearing temperatures are recorded for comparison to previous visits. These are often available in the PLC for the chiller, or our engineer can take the readings with his test equipment. Problems with the oil cooler can be the cause of higher compressor temperatures, the system running outside of its nominal operating conditions is another reason. Magnetic drive systems have an advantage as they do not use oil.

Accelerometer

Portable vibration sensors are carried in of each of our company vehicles. This is an accelerometer to measure vibration. Along with other system readings, we keep an on going record of the vibration levels around the compressor. When internal components are coming out of alignment due to wear, this causes an out of balance condition in the compressor. This, in turn, causes a knock on effect- causing other components to go out of balance. Catching this condition early will prevent a compressor smash up resulting in the replacement of expensive internal components.

Oil Analysis for Chiller Compressors

Another way of preventing big problems from occurring is periodic compressor oil testing. Samples are taken, usually on alternate visits, which are sent off to a laboratory for analysis. The acid level is tested to provide pre warning of a potential compressor motor windings burn out. This is because acid in the compressor oil rots through the electrical insulation on the motor windings. The presence and quantity of white metal and yellow metal is analysed too. This is a window through to a component starting to wear inside the compressor.

0161 370 7193

service@maximuschillers.com

Contact Form

Screw

The compressor in the photo is a screw compressor. It operates with ammonia refrigerant. This refrigerant is usually used for low temperature applications, mainly associated with food production. This compressor, however, has a 1°C refrigerant saturation and is used to cool computer rooms. Common causes of compressor failure on this kind of compressor are:

Leaking Castings on Chiller Compressors

The various compressor components are sealed together using ‘o’ rings or paper gaskets. ‘O’ rings are especially prone to leaks due to work hardening and flattening of the sealing face. The system can be pumped down and the compressor valved off. Then, our lift and shift team can remove the compressor to our remanufacturing facility for strip down.

Leaking Shaft Seal

The mating surface of a shaft seal has a mirror smooth finish. This is to reduce friction and aid with a better seal. Over time, this starts to wear, causing an ineffective seal with a leak of refrigerant and oil. A service visit can be arranged to change the shaft seal on site. The shaft couplings can be split, the shaft seal can then be removed and replaced. A quick job, then the machine is up and running again.

Slide Valve Potentiometer

This is an electronic device with a slide attached to the moving compressor slide valve. The device has a start and an end position programmed into it during commissioning. The potentiometer converts the slide valve position, usually into a 4-20mA signal which is fed back to the chiller PLC. They are prone to reading out, or the reading being jammed in one position. This results in a trip out from the controls, as the controller is not able to determine the true position of the compressor slide valve. We have an off the shelf stock of slide valve potentiometers for the various compressor range. A service visit can be arranged to replace the part after diagnosis has been carried out. The controls operate the loading and unloading solenoid valves to change the position of the slide valve.

0161 370 7193

service@maximuschillers.com

Contact Form

Centrifugal

Centrifugal compressors are a very reliable kind of compressor but when they go wrong, they can go wrong in a big way. Compressor overhaul is expensive, this can be carried out onsite, or a better option is a lift and shift to our remanufacturing facility. Proximity sensors are usually fitted to monitor the distance between the impeller and the casting. This is an added protection along with the other sensors and transducers around the compressor.

MCS

We are on account with Micro Control Systems- an American company who specialise in building panels to order for specific chiller compressors. We easily fit this control system to any compressor to control the loading of the vanes in accordance to the available load from the process. The control panel has previously been fitted to other machines of the same model number, so any teething issues have already been ironed out. Maximus Chillers can achieve seamless operation of your plant.

Oil System for Chiller Compressors 

Newer centrifugal compressors are oil free so as to eliminate any of the service issues relating to oil. There are a substantial amount of compressors, however, that use oil to lubricate the bearings. This kind of compressor, if properly serviced, can last for 50 years. The oil system picks up impurities which are caught by various filters. These filters can be changed or cleaned according to the prescribed service schedule. Our engineers make sure that spares are ordered and kept onsite prior to a visit.

Cost Effective

Our visits and ongoing upkeep of your plant saves money. Money spent as a preventative measure saves so much more money in the long run. With competitive prices on specialist internal centrifugal compressor parts- Maximus Chillers completes the picture. When compressor failure occurs, you are in safe hands with years of industry experience invested in each of our engineers.

0161 370 7193

service@maximuschillers.com

Contact Form

Scroll

These are some issues affecting a scroll compressor:

High Discharge Pressure

With high discharge pressure, there is a corresponding increase in discharge temperature. This means that the compressor is operating beyond its recommended values. The cause of this is often a poorly maintained condenser. Especially on industrial chillers, there can have been gaps in the schedule where the condenser was not correctly serviced. This condition is often rectified easily by an onsite engineer by giving it a brush down. Where the fins are bent over- we carry a specialist tool to straighten them back out- how they came out of the factory. We also use different formulas of chemicals to rinse the various kinds of dirt from deep within the fins.

High Suction Pressure on Chiller Compressors 

Some chillers are used where very high water temperature can come back from the process if the chiller were to be off line for a short period. Usually, this happens in factories where certain industrial processes are being carried out. When the onsite engineers start the plant back up, the chiller experiences a high heat load to deal with.

MOP Expansion Valves

Maximum operating pressure expansion valves limit the pressure in the evaporator to a given level, regardless of the available heat load from the process. They do this by having a limited amount of liquid refrigerant in the bulb. When this runs out, the power element cannot push the orifice open any further- thus limiting the suction pressure. This is important to prevent scroll compressor failure as it prevents putting added strain on the compressor motor windings due to high suction pressure.

Oil and Refrigerant Shortage

Where there is a shortage in refrigerant, there follows a low oil level condition. The refrigerant mass flow rate carries the oil around the system and back to the compressor. This is greatly impaired when the chiller is short of gas. The oil cools the compressor and lubricates the shaft bearings. These bearings and other internal components wear down and seize causing failure. Maximus Chillers can put together a package to minimise chiller compressor failure.

People also like this page:
Centrifugal Compressor Remanufacturing

Related Articles:
Screw Chiller Compressor Maintenance

Chiller Parts Supplier

Air Cooled Chiller Condenser Maintenance

Shell & Tube Evaporator Maintenance

Scroll Chiller Compressor Maintenance

Chiller Controls

Centrifugal Chiller Compressor Maintenance

Chiller Condensers

Reciprocating Chiller Compressor Maintenance

Chiller Controls Company

How Do Chillers Work

To read more about scroll chiller compressors hit the Tag at the top of the page.

Read more about impellers which are used in centrifugal compressors at Wikipedia


PLC and relay board in a panel during chiller service company visit

Chiller Service Company

Electrical Testing

A chiller service company can carry out electrical testing and diagnosis even when a wiring diagram is not available- our engineers can trace the wiring around a chiller.

News Article No.3

Doing this often aids with the diagnosis even when there is a wiring diagram, as having your eyes on a component often makes more sense than a symbol. In any case, our engineers carry out system testing with Fluke multimetes and ammeters.

F-gas Leak Testing by Chiller Service Company

We also carry a range of thermocouples and probes to be used in conjunction with our calibrated digital thermometers. We use these along with comparators to carry out leak testing. After fitting the probes, we first have a visual look around for a sign of a gas leak. All parts of the pipework and system components are inspected. Then, we carry out a full refrigerant diagnosis to determine that the refrigerant system is operating with a full charge. Reports for each chiller are completed and filed in the onsite F-gas leak register. A history can be built up to assess the serviceability of the plant and the frequency of any leaks.

Chiller Service Company Monitoring

Where intermittent faults are concerned, on site monitoring is required. If the job is not progressed on each visit, there is little point in a call out. We carry out tests during monitoring and ensure that the wiring is tight. Hopefully, waiting for the fault to occur whilst next to the machine. Alongside this, we rely on feedback from the end user, as regards, the symptoms and the circumstances of the chiller when the fault occurred. From this we extrapolate the diagnosis and decide the next step to take. This may be to attempt to move the fault to another machine or, at least eliminate one thing each visit.

0161 370 7193

service@maximuschillers.com

Contact Form

Chiller Service Company Evaporators

Shell and Tube

These have a rolled steel shell, welded down the seam with and end plate on either end. The water system pipes can be bolted to the sides or the end. The endplate can be removed for access to the waterside of the tubes. A strainer is fitted to the inlet to catch any foreign objects that may have been carried around the water system. Inlet and outlet gauges are fitted for the monitoring of the water system readings during a visit. 

Flooded

On larger chillers, the screw or centrifugal compressor is mounted directly on top of the flooded evaporator. The refrigerant is in its liquid phase on the outside of the tubes. These are arranged in a rack extending through the length of the shell. The warmer process water running through the tubes causes the refrigerant to boil off. A sight glass is usually available to check the state of the refrigerant evaporating on the copper tubes. The suction from the top of the evaporator goes round a baffle so as to prevent the slug back of liquid refrigerant into the compressor. The refrigerant flow into the evaporator is controlled by the expansion valve…

Expansion Valves

This takes the form of a fixed size orifice on the liquid line in between the shell and tube condenser and the flooded evaporator. The size of the orifice previously being calculated to match the mass flow rate of the refrigerant dictated by the compressor. Some newer systems have a variable orifice for the more efficient running of the plant. This is controlled electronically along with the loading of the compressor, relative to the available load.

Multiple System N+1

Smaller DX evaporators are usually multi system. This gives an N+1 redundancy of the plant. Indeed, when one side of a 2 system evaporator is having service work carried out, the other side continues to operate normally. Thinking ahead and allowing for additional capacity is essential when the application is critical, such as, a data centre or a hospital. When a redundant system comes online due to a failure- getting the failed system back up and running is a matter of urgency. For this we offer same day delivery of parts and a fully stocked mobile workshop.

0161 370 7193

service@maximuschillers.com

Contact Form

Chiller Service Company Condensers

Various configurations are employed to ensure good air flow through the condenser fins. The most popular being a ‘v’ condenser as the surface area is increased with this design. Powerful fans are used to reject the air and heat upwards and away from the chiller. Where system location causes the recirculation of air, duct work can be fitted to direct the air away from the chiller. The pressure is monitored using a HP gauge.

Pressure Transducers

Johnson Controls

A popular kind of pressure transducer that is used on condensers is Johnson Controls. These can be bolted onto the refrigerant discharge pipe to sense the system pressure. They have a 5vdc input that comes into the transducer on a red wire, a black wire is the ground and a white wire is the signal back to the fan speed controller. The transducer has a minimum to maximum range, so a chart can be used to determine if the signal is reading back correctly. On chillers where the transducer is wired directly in the controller- calibration can be carried out to offset the readings.

Keller

Another kind of pressure transducer is the 4-20mA type. It sends a mA signal back to the controller or the fan speed controller. 4mA is the minimum position, so this relates to the minimum of the transducer pressure range.

R134a Refrigerant

R134a refrigerant operates at a lower pressure in a condenser than the other commonly used HFC refrigerants. If you were looking for a chilled water set point of 6°C in the UK ambient for example, the R134a refrigerant saturation on the high side of the system would be around 36°C Latent heat from the water system and heat added into the refrigerant from the compressor are rejected from the condenser. As the refrigerant passes down the condenser tubes, cool air blowing across the outside of the tubes, cools the refrigerant vapour down through the latent heat phase and into a subcooled liquid.

0161 370 7193

service@maximuschillers.com

Contact Form

Chiller Service Company Compressors

Centrifugal Compressors

This kind of compressor has a lower volumetric efficiency compared with the positive displacement compressors below. This is because the refrigerant is compressed using centrifugal force off the tip of the impeller, instead of being mechanically compressed. The advantage of this kind of compressor is a high mass flow rate of refrigerant. These compressors are used in factories where a large amount of chilled water is required to cool the process. They are also used in countries where district cooling is used. The chillers are arranged in rows in a chiller hall and are piped into the district cooling loop.

Screw Compressors

Oil used to lubricate the bearings is also used to create a seal between the rotors. Computer aided design (CAD) software and computer numerical control (CNC) grinding machines are used in the construction of screw rotors. The shape of the rotors is designed to compress the refrigerant along the screw. The length of the screw that is available to compress the refrigerant can be adjusted with a slide valve. Any stage of loading between 0- 100% can be achieved. This is regulated with a slide valve potentiometer. Screw compressors are very reliable and have a long service life. They also have a low vibration reading which ensures a lower instance of refrigerant leaks around the compressor.

Scroll Compressors

A service free compressor. Service free assuming that the rest of the system is functioning correctly. This kind of compressor relies on oil migration around the system. The oil is entrained along the inside of the pipework, around the system and back to the compressor. An oil level sight glass is fitted into the body of the compressor at the required level. Refrigerant shortage can cause the oil to stay in the bottom of the evaporator, causing a low oil level condition in the compressor. We can be scheduled to attend site to drain the oil, then pump new oil into the compressor.

Compressor Failure

When any of the above compressors fail, you are in safe hands with Maximus Chillers. We have the capability to lift and shift the compressor to our remanufacturing facility for a full overhaul. The reason for the failure is diagnosed to ensure the new compressor does not fail for the same reason. Improving the reliability of your plant and extending its life is what we are all about- if we can reduce your service costs- that makes us happy! All temperatures and pressures are recorded to ensure the replacement compressor goes into seamless operation.

Any Chiller- Any Problem- Any Part- Any Refrigerant- Anywhere- The MAXIMUS ADVANTAGE™

Related Articles:
Chilling Plant Service

Chilled Water System EEV Service

Water System Service of Evaporator

HFC Chiller Service

Process Chiller Vacuum Service

Chiller Breakdown

Industrial Chiller Service

Chiller Service Company Visit

Chiller Fault Finding & Diagnosis

F-gas Chiller Leak Testing

Chiller Commissioning

Air Cooled Chiller Condenser Testing

To read more about chiller diagnosis hit the Tag at the top of the page.

Read more about pressure sensors on Wikipedia


A pile of completed chiller maintenance checklists on a table

Chiller Maintenance Checklist

Introducing a series of in depth news articles, this time featuring the chiller maintenance checklist:

News Article No.1

This article has been written with you- the customer in mind. Read below for practical advice on how to keep your chillers in the best condition.

Each day when you walk round, you can check to see if your plant is starting to malfunction. Become accustomed with the usual readings to help you diagnose the faults.

Here are the things to check for and how to remedy them:

Water System Pressure

Keep an eye on the pressure in the water system.

Small Chiller Maintenance Checklist

On a small chiller, there will be a water outlet pressure gauge. Make a mark on the gauge where the pressure is when the chiller is in good working order. You can use this mark to notice if the pressure is starting to drop off.

Strainer

The most common cause for low water system pressure is a blocked strainer. It is usually a ‘Y’ type with a bolted fitting. With the chiller off and the water system valves closed, unscrew it and check for debris. If it is blocked, make a note of how long it took to block, then add the cleaning of the strainer into the periodic maintenance schedule.

Pump

Ensure the pump rotation is correct by checking that the cooling fan is sucking into the pump. If it is going backwards: isolate electrically, then swap any 2 of the 3 phase wires. Brush down the inlet to the cooling fan to ensure good air flow and a cool pump motor.

Large Chiller Maintenance Checklist

On a large chiller, the water system pressures may be available in the controller- have a look through the menus. The pressure will be measured in bar. Another popular method on a large chiller is a flow meter. This may be a stand alone device on the chiller panel, or on a control panel nearby. It will read in m3/hr. Check to see if the pressure or flow is lower than usual. If so, ring one of our trained professionals.

0161 370 7193

service@maximuschillers.com

Contact Form

Water System Temperature

The chiller should be:

  • Matching the load and running continuously.
  • Loading and unloading in sequence with other chillers.
  • Going through a cycle and achieving set point.

In any case, you will become accustomed with the usual chilled water temperature according to varying load conditions. If the plant is struggling to achieve set point, or is running higher than usual- this is a sign of system faults.

Walk along the chillers that feed the same water system and make a log of the faults showing on the controllers.

Here are the things to check when you have high water system temperature:

Small Chiller Maintenance Checklist

Low Pressure

If the chiller has a low pressure gauge, look to see if the pressure is lower than usual. If so, this is a sign of refrigerant shortage in the plate evaporator. A scheduled visit from one of our trained engineers to carry out a pressure test can be arranged.

Breakers

Look for any breakers that have tripped in the panel. One reset can be carried out by a qualified onsite electrician. If the fault reoccurs- ring our support team. If the scroll compressor has tripped, check to see if the compressor is hot. If so, isolate and do not attempt a restart.

Condenser

A blocked condenser will inhibit the rejection of heat. Brush it down and give it a rinse with water. A common occurrence onsite with some condenser designs is a panel being left off with the chiller running! This happens when the onsite engineers are fault finding another issue with the chiller. The fans will suck through the opening as this is the easiest path. The gauge will be higher than usual as the condenser builds in pressure. A high pressure trip out will occur.

High Pressure Switch

To locate the switch- first identify the discharge pipe. It is the smaller of the 2 pipes on the compressor. The high pressure switch will either be bolted onto the pipe, or a thin pipe will lead from the discharge to the frame of the chiller. In any case, you are looking for a small box with a button and a wire leading to the panel. Press the button and you should hear it click. If this fault reoccurs- ring our technical support desk.

Large Chiller Maintenance Checklist

Suction

Should there be a refrigerant shortage, the controller will display a pre alarm like 'suction limiting' This is the controller preventing the compressor from loading up, so as to prevent a low pressure trip out. As above, one of our team of engineers can be sent to site to resolve the issue.

Discharge

If the controller is showing 'discharge limiting' this is a sign of a condenser issue. A full strip down and cleaning of the tubes may be required. Ring our technical support desk for further advice.

0161 370 7193

service@maximuschillers.com

Contact Form

Chiller Remote Monitoring

We at maximus chiller can install remote monitoring systems to your chillers so we can fault find and diagnose from a laptop. This means we can give you real time advice over the phone. Now you are accustomed with our chiller maintenance checklist, you can give feedback regarding the plant to assist our engineer.

Parts

For our contract maintenance customers: a range of commonly used parts are kept onsite to reduce downtime. We can give practical, step by step advice on the fitting of parts. We often carry out video calls with our customers, as chiller data plates, parts and components can be easier to show than describe.

Any Chiller- Any Problem- Any Part- Any Refrigerant- Anywhere- The MAXIMUS ADVANTAGE™

Related Articles:
Air Cooled Chiller Planned Maintenance

Water Chiller Maintenance

Process Chiller Maintenance Visit

Chilled Water System Maintenance

Centrifugal Chiller Maintenance

Industrial Chiller Maintenance

Air Cooled Chiller Condenser Maintenance

Glycol Chiller Maintenance

Chiller Maintenance Schedule

Air Cooled Chiller Maintenance

Chiller Maintenance Company

Chilling Plant Maintenance

Preventative Chiller Maintenance

To read more about air cooled chiller condensers hit the Tag at the top of the page.

Read more about chillers on Wikipedia


Yellow oil drums, ammonia refrigerant cylinders and flammable flushing agent of chiller supplier

Chiller Parts Supplier

Chiller Parts Supplier of Compressors

Centrifugal

As a chiller parts supplier, all kinds of centrifugal compressors are remanufactured in our workshop. With an overhead gantry crane and specialist equipment to hand- Maximus Chillers completes the picture. We have a lift and shift team who are skilled at getting the compressor out of the most awkward locations. A variety of lifting equipment is used, including 3 phase electric hoists and trollies. Our team do this kind of work all the time, so they are accustomed to overcoming all the difficulties and obstacles.

Screw

Screw compressors are remanufactured on the bench. With compressed air and bearing tools- our skilled technicians are seasoned in high tolerance measurements. The bearing clearance and shaft run out are accurately measured and adjusted. This means that the useful life of the compressor is extended, often to beyond the lifespan of the chiller.

Scroll

We have a range of off the shelf Copeland compressors for a fast lead time on process chiller repairs. These can be sent to site on the day using our fast door to door supply chain. We have all the sizes of compressor available. The pipework and mountings can be adapted too. This means that if your compressor is a different make with a longer lead time- our compressor will be fitted and adapted to your machine- fast!

Chiller Parts Supplier of Condensers

Air Cooled

When the condenser on an air cooled chiller is in poor condition- our site survey team will attend to measure up for a new bespoke condenser. This is done free of charge and ensures that the new condenser will fit easily into the old chiller. The exact subcooling requirement of the old condenser is taken into account which is duplicated on to the new condenser. This means a like for like swap can take place even when the old condenser is obsolete.

Shell and Tube

This type of condenser is used on water cooled chillers. It is protected from contaminants by a strainer on the water system. We have these condensers built to order by our bespoke manufacturer. They are shipped to site on an overnight delivery, so we can get straight down to work in the morning. We therefore minimise downtime in the swap out of this part.

Chiller Parts Supplier of Evaporators

Shell and tube are the most popular type of evaporator for large chillers. The low temperature refrigerant is on the outside of the tubes in liquid form. The water is pumped through the tubes, releasing heat from the process and into the refrigerant. This is latent heat as the liquid refrigerant boils off into a vapour. Where the heat exchange does not greatly improve after cleaning, we recommend replacing this part.

0161 370 7193

service@maximuschillers.com

Contact Form

Vibration Eliminators

We have all of the sizes of anacondas on the shelf in our stores. This saves on the delivery time to site when your process is off due to the chiller. Maximus Chillers will get you up and running- fast! We can also fit flexible vibration hoses which achieve the same result as anacondas. Whereas two anacondas are fitted vertically and horizontally, only one, long vibration hose is needed.

Chiller Parts Supplier of Flushing Agent

When things go wrong, we stock a solvent based flushing agent which is blown through the system using nitrogen. The waste product is caught on the far end in drums that come with the kit. This is then returned to the suppliers for recycling.

Refrigerant Economizers

These are another term for a subcooler. If the refrigerant is further subcooled after the condenser- the system will run more efficiently. This part usually takes the form of a plate heat exchanger with an expansion valve providing the refrigeration effect needed to further subcool the remaining liquid.

Chiller Parts Supplier of Pressure Transducers

We can make temporary repairs to faulty pressure transducers using our test equipment. This will keep your plant running while the part arrives on site. Then we can get your chiller up and running with the correct readings in the controls. This will assist your onsite maintenance engineers in giving us useful readings when we are in communications over the phone.

Chiller Parts Supplier of Ammonia and HFC Refrigerant

A full selection of refrigerants are available including: anhydrous ammonia, R407c, R134a and R410a. These refrigerants come in small 12kg, midi 26kg, large 56kg and bomb 800kg sizes. Our vehicles are equipped with tail lifts and lifting gear to facilitate delivery. We can therefore arrange the delivery and collection of refrigerant at your site, free of charge, anywhere in the UK. For our overseas customers, we arrange the transportation from the local suppliers.

Chiller Parts Supplier of Oil

Low, medium and high viscosity oils in 5ltr cans and 20ltr drums are ready for shipping from our storage area. It is critical to select the correct grade of compressor oil as bearing wear and reduced service life will result. We take regular samples of this oil to see if things are starting to go wrong in the compressor. We can then nip these problems in the bud, giving you dramatic savings.

Any Chiller- Any Problem- Any Part- Any Refrigerant- Anywhere- The MAXIMUS ADVANTAGE™

Related Articles:
Screw Chiller Compressor Maintenance

Chiller Compressors

Air Cooled Chiller Condenser Maintenance

Shell & Tube Evaporator Maintenance

Scroll Chiller Compressor Maintenance

Chiller Controls

Centrifugal Chiller Compressor Maintenance

Chiller Condensers

Reciprocating Chiller Compressor Maintenance

Chiller Controls Company

To read more about chiller evaporators hit the Tag at the top of the page.

Read more about the dangers of odourless refrigerant at the Institute of Refrigeration


Process chiller maintenance of grey Italian chiller with cover removed

Process Chiller Maintenance

Maximus Chillers recently carried out process chiller maintenance to an Italian machine.

Process Chiller Maintenance for Water Level Sensor

The process chiller has a water treatment schedule, but the water level sensor needed maintenance. This is because the three probes of the sensor were not completing continuity. The probes complete the continuity from the wire going into the sensor, along the probe, then to another wire back to the controls of the chiller.

Low Water Probe

If the controls loose continuity to the low water probe, the alarm is triggered and a call out is arranged to resolve the issue.

Correct Level Probe

In normal operation, the correct level probe is activated and the chiller runs as normal.

High Water Level Probe

Should the high water level probe be activated, again the alarm is triggered and a call out arranged.

0161 370 7193

service@maximuschillers.com

Contact Form

Process Chiller Maintenance Call Out

As we were already on site to carry out the maintenance, there was no need to arrange a call out. We soaked the sensor for an hour in a special a decontamination chemical that has been designed to restore the probes. That done, the rest of the maintenance was carried out including the tightening of the wiring and motor connectors. It was possible to do this on this visit as the factory was not in production.

Run Testing

All readings around the chiller were taken when the factory went back into production. We found the fridge system to be working with optimum efficiency, meaning that the chiller will use the optimum amount of electricity. Efficiency is a great concern to a factory as they want to reduce their carbon footprint as much as possible.

Related Articles:
R134a Chilling Plant Maintenance

Water Chiller Maintenance

Air Cooled Chiller Planned Maintenance

Chilled Water System Maintenance

Centrifugal Chiller Maintenance

Industrial Chiller Maintenance

Air Cooled Chiller Condenser Maintenance

Chiller Maintenance Checklist

Planned Preventative Chiller Maintenance

Chiller Maintenance Schedule

Air Cooled Chiller Maintenance

Chiller Maintenance Company

Chilling Plant Maintenance

Preventative Chiller Maintenance

Read about the IOR celebration of service engineers


Translate