Monthly Archives: September 2019

Industrial Refrigeration Service of the Refrigerant

Industrial Refrigeration Service

We recently carried out an industrial refrigeration service to a plant due to a refrigerant leak. The customer had reported that the ammonia leak alarm had gone off and the plant had shut down. When he went to investigate, a strong smell of ammonia was coming from the compound

Industrial refrigeration service

The Leak

We arrived on site promptly, well within our usual call out time. On assessing the situation, our engineers decided to ‘don’ breathing apparatus BA and full length ammonia grade personal protection equipment PPE. The leak was easy to find as anhydrous ammonia was still coming from a 1/4” pipe fitting on an oil return eductor. It had worked loose due to the vibration of the plant. He ‘nipped’ it back up with his adjustable spanner and the leak stopped. After the dispersal period for the leaked ammonia, a trace leak test was carried out to the fitting and the decision was made to ‘doff’ the BA and PPE

Testing the Plant

There was found to be no subcooling in the low pressure receiver, high superheat and the compressor was being held back from loading up. The various sight glasses were showing poor running conditions too. Refrigerant shortage

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Fast Same Day Delivery

The end user was worried that should the other plant need service, he would loose his production. We arranged our fast, same day delivery service of 4x 56 kg ammonia cylinders that arrived in a couple of hours

Industrial Refrigeration Service of Ammonia

Servicing the industrial refrigeration ammonia charge was straight forward. The system has a service port on the header tank. While the system is running, the header tank pressure is considerably lower than the cylinder. Our cylinders come with a dip tube, so liquid is easily sucked into the plant. When the low pressure receiver subcooling came down to nominal readings along with the sight glass readings, we were happy that the plant was back in service

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Chilling Plant Service

Chilling Plant Service

Our customer had been having high pressure service problems on his chilling plant

Transducer Required Chilling Plant Service

The 4-20mA transducer needed service on the chilling plant. It was reading low by a long shot. Therefore, the PLC was not bringing the fans on as it should. The pressure in the high side of the system was getting up to 40 bar. This is because the refrigerant was R410a- it has a higher head pressure than other commonly used HFC refrigerants, such as, R407c. We ordered the replacement transducer which is fitted with a female fitting

Chilling Plant Service Leaks

He concentrated his attention on the high side of the system to start with. Then, found a leak on a fitting, a leak on the pressure relief valve fitting and a leak on the liquid line near the drier. The leak on the fittings were re sealed with Loctite- they were removed, cleaned and refitted. The leak on the liquid line was re sealed by removing the section of pipe, removing any remaining solder then the section of pipe was re made

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Pressure Test

The remaining parts of the system were leak tested then the chilling plant was put on a pressure test to ensure the whole system was leak free. The pressure test was satisfactory and so the evacuation process could be started

Evacuation Process 

Each of our engineers has a powerful vac pump to speed up the dehydration process on the chilling plant being serviced. This means that a deep vacuum can often be pulled on the same day instead of the usual overnight process. The nitrogen and other non condensables were removed quickly and the Torr gauge came down to the pressure where moisture was being removed. At this pressure, any moisture is forced to boil off around the system

Recharging of the Chilling Plant Being Serviced

In the photo, the chilling plant is being recharged at the end of the service work. It is being recharged into the liquid side of the evaporator. All readings were okay when running the system and further leak tests were carried out at normal operating pressures

Read more about refrigerant reclamation by following this link to Wikipedia | Click Here

Chiller Condenser Retrofitting

Chiller Condenser Retrofitting

We recently undertook the job of having a bespoke 'V' chiller condenser retrofitted for a customer of ours 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, however and when an attempt to repair a leak had been carried out- the condenser would leak further along. This is because of the warming rusted and corroded copper with an oxy-acetylene torch

Chiller Condenser Retrofitting

Our supplier arrived on site to measure up for the job. The ‘V’ chiller condenser being retrofitted was built to order. Exact replicas were made to the same specifications and sizes of the old ones. The operating pressures and high pressure cut out limit were taken into account in the design and the use of materials

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Lift Out of 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 had to be ground off with an angle grinder. 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 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

Read more about air cooled condensers at the Institute of Refrigeration Click Here

Carrier Chiller Service in Moscow

Carrier Chiller Service

Category : chiller service


Our customer in Moscow had been emailing our technical support desk regarding the service of his Carrier chillers

Flow Issues

There had been ongoing issues with blocked strainers on the water system. Each time they were cleaned, they blocked back up again. A large dirt trap near to the chiller also needed to be repeatedly cleaned out. A problem with dirt being carried round the water system

Flush Out Service for the Carrier Chillers

The end user had employed a local company for a flush out service for the Carrier Chillers. The company first drained the water system and refilled it with various chemicals. There is a chemical to lift the dirt off the inside of the pipe. Another chemical to carry it back. Another chemical to bond with the heavier elements

Carrier Chiller Service Readings

The readings taken during the Carrier chiller service were wrong by a long shot. There was a serious restriction in flow to the chiller. Safety devices were activated on the chiller to prevent system failure. If not for these safety devices- the chiller would be ruined. More than one device was preventing the chiller from freeze up

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Service of the Water System

The water system was drained down to service the plant. The inlet to the evaporator was removed for inspection. A Considerable amount of sludge was found to be blocking the inlet to the evaporator. The pipe was bolted back on, the water system was refilled then emptied in the reverse direction to the water flow. The water system was filled again and system readings taken

Service to the Carrier Chiller

The service to the Carrier Chiller was found to be satisfactory as the water system readings were okay. No safety devices were being activated and a good run was achieved from the Carrier chiller. All other readings were taken as part of giving the chiller a full heath check. As always a detailed Tick Sheet was completed. Our engineer demonstrated to the on site engineers how to back flush should the issue arise again

Read about legionella and how it can affect a chilled water system on Wikipedia