Air Cooled Chiller Condenser Maintenance

7 large air cooled chiller condensers maintained with 12 fans each

Air Cooled Chiller Condenser Maintenance

Air cooled chiller condenser maintenance at Maximus Chillers. The condensers in the picture are a row of 6. These are remote from a row of 6 chillers, located in a plant room in the building below. The chillers are 750 kw single screw compressors with a control panel located to the side of each. On this visit, the emphasis of the maintenance was scheduled as being to the condensers.

Fan Speed Controllers

The refrigerant for the systems is R134a, so to allow for the saturation of the refrigerant, 8 bar is the head pressure set point. This pressure corresponds to the desired condenser temperature of 36°. Subcooling of 6° to 8° is achieved during the nominal operation of the plant. Each fan speed controller runs the 12 condenser fans together. Other condenser designs where fans bang on forwards and backwards cause vibrations resulting in reoccurring leaks on the condenser. Chiller No. 2 had tripped during a “discharge override” system message. On inspection of No. 2 condenser- the fans speed inverter had tripped on “over temperature” alarm. The panel fan, which is the kind to cool computers, was found to be still trying to run but seized. This failure had caused the alarm on the inverter. The panel fan was replaced from the stock of parts in the on site stores. The chiller was reset and a detailed Tick Sheet was completed noting the occurrence of this fault on arrival.

0161 370 7193

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Air Cooled Chiller Condenser Wash Down Maintenance

Because of the large size of the plant, the customer had installed a fireman’s hose for the wash down of the condensers during air cooled chiller maintenance. This is located in the free space beneath the condensers. It is fitted to a portable buggy so it can be moved under each condenser. Setting the nozzle to the correct attitude, our engineer moved the buggy sideways, so as to rinse the condenser in the direction of the fins. The condenser was relatively clean as the on site maintenance engineers carry this task out as part of their scheduled maintenance.

To read more about air cooled chiller maintenance click the Tag at the top of the page.

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R134a chilling plant maintenance showing screw compressor and oil separator with tick sheet and digital thermometer on top

R134a Chilling Plant Maintenance

We recently carried out R134a chilling plant maintenance at our customer’s factory in the North West. The chiller is 600kw with 2 single compressor systems. It has an ‘in house’ controller on it with occasional spurious trip outs. We are working with the problem so far, but an option if the problem persists is to fit a reliable, cheap, off the shelf controller. The factory requires a process water temperature of 6°. The plant is around the middle of the lifespan and has been properly maintained.

R134a Chilling Plant Maintenance Checks

Unlock Controller

The customer had accidentally locked the controller by pressing the wrong buttons. The machine still functioned as it should, but the customer was unable to modify User settings or look at the readings. Our engineers carry a book with an extensive list of information for any controller which has been built up over time. The procedure was followed to unlock the controller, then the settings were checked.

0161 370 7193

service@maximuschillers.com

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R134a Chilling Plant Sensor Maintenance 

The sensors can be offset to compensate for a sensor reading out slightly. No offsets were saved and the sensors all read to within a degree or two of our digital thermometer. Our engineer then checked the sensor locations to ensure they were fitted correctly and insulation had not deteriorated.

Fan speed Controllers and Subcooling

During the R134a chilling plant maintenance, particular attention was paid to the fan speed controllers and the subcooling of the refrigerant. This is because of occasional spurious high pressure trips. All the wiring was tightened and the plugged connections were checked and tested. The controller sends a variable run signal to the fan speed controllers. This is worked out from the analogue input signal from the high pressure transducer. If the problem persists, we will have to look into fitting more reliable head pressure controls.

Compressor Slide Valve

The oil solenoids which push and pull the compressor slide valve were operating correctly. The controller sends volts to the solenoids to control the position of the valve. A slide valve sensor sends feedback so the controller can work out the percentage position of the valve.

To read more about chilling plant maintenance click the Tag at the top of the page.

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A chiller condenser retrofitting lifting operation outside in the compound

R407c Chiller Condenser Retrofitting

We recently undertook the job to carry out bespoke R407c chiller condenser retrofitting in the North West.

Rusted and Corroded Condenser

The old condenser looked alright on the surface- the fins were in good condition. The chiller condenser was 18 years old and when an attempt to repair a leak was carried out- the condenser leaked further along. This is because of the warming of rusted and corroded copper with an oxy-acetylene torch.

R407c Chiller 'V' Condenser Retrofitting

We arrived on site to measure up for the job. The ‘V’ chiller condenser being retrofitted was built to order. We manufactured an exact replica to the same specifications and sizes of the old one. The operating pressures and high pressure cut out limit were taken into account in the design and the use of materials.

0161 370 7193

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Lift Out of the R407c Chiller Condenser being Retrofitted

On the day of the lift and shift we isolated the panel and checked it was dead, then we removed the panel and laid it on it’s front. This was to access the rivets behind the panel. These rivets, the ones on the other end of the chiller and around the lid were removed using a tool. The fans were disconnected and removed to make the lid lighter to lift off. Then, we attached slings to the chiller condenser and lifted both halves of the 'V' out.

Lift In of the Chiller Condenser being Retrofitted

This part we did not want to get wrong as the R407c chiller condenser being retrofitted was brand new and did not have a mark on it. A reverse of the removal- it fitted perfectly just the same as the old one. With the lid lifted back on and the fans in- time for brazing then the pressure test.

Pressure Test, Dehydration and Recharge

The pressure test was satisfactory so our engineer put the system on vac for dehydration purposes and the removal of non condensables. After a deep vacuum was achieved the system was recharged and run tested. No issues were found.

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Chiller service of fan decks showing 8 fans

Chiller Service of Fan Decks

Chiller Service of Fan Decks Bodger Watch

Chiller service of fan decks is usually very good, but this is bodger watch! A new customer of ours was telling us about this little guy that used to come to carry out chiller service of fan decks. He was reported to have been running around like the apprentice- ringing everybody up! Then when help came, it came in the form of this huge big man who proceeded to get stuck in the chiller! You couldn't make it up! This is bodger watch! The customer asked for a professional service from Maximus Chillers.

Repeated Leaks on Condenser

Our engineer found the head pressure control was bringing the fans thumping on and off forwards and backwards. During a visit, the fans were found to be rattling the frame and juddering the chiller into leaks.

0161 370 7193

service@maximuschillers.com

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Learning How to Think

Instead of just swapping like for like parts. Our engineers have the capability to think outside the box and make changes to chiller design. All of our engineers attend the Maximus School of Chillers at Head Office in Droylsden, Manchester. Read More on the Chiller Company page.

Fan Speed Controller

On a return visit, we fitted off the shelf fan speed controllers from our stores- one for each system. These fan speed controllers are stand alone- they do not need to be integrated into the existing controls. When the pressure builds up- the fan speed controller speeds the fans up from the minimum (cut in) to the maximum (same volts as the incoming supply)

Chiller Service of Fan Decks Seamless Operation

Now the fan speed controllers are fitted- there are no more leaks. Any chiller can be made to settle down into seamless operation.

Are you a factory manager or facilities manager with recurring leaks on your chillers? Look no further than Maximus Chillers.

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Visit the Institute of Refrigeration to read a paper on the comparison between air cooled condensers and evaporative condensers.


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