Water Chiller Repair

Looking down on 2 large water chillers under repair

Water Chiller Repair

Water chiller repair following cowboys who had previously carried out poor works. Luckily, there are not many bad eggs in our industry- but there are a couple. A bodger watch way of shortening a job would be to skip the pressure test and the vacuum, then just purge the system through with refrigerant. Any engineer worth their salt knows that this does not remove the air that has got into the system. This is because purging can’t remove the air from around the complicated internal pipework. The reason for this kind of shoddy repair is that bad engineers would rather be off site doing their own thing. To add insult to injury, you- the customer still get charged for the time the engineers should have been on site but weren’t.

Bodger Watch

Because we sorted out various other problems on the first day of the contract, this customer is really happy with Maximus Chillers. We have a 3 year Maintenance Contract with them too. Bodgers are also carrying out similar shoddy jobs to other customers’ chillers. We are in the process of going round to where bodgers have been up messing the chillers and winning the contracts. With cowboys like these going round in front of you- it is like taking candy from a baby. Not hard to win the confidence of a new customer when rotten apples like that are damaging water chillers.

Water Chiller Repair Industry Standards

When we had to inform the customer of the above, all we could do was apologise on behalf of an otherwise good industry. We explained the science of how the above problem was diagnosed as follows…

Dalton’s Law of Partial Pressures

That all gasses in a vessel will act as if they are on their own. The air in the system works its way round to the condenser where it sits on top of the liquid refrigerant and won’t condense. This is where the term non condensable comes from. Let’s say the condenser pressure should be 8 bar on a system running with R134a refrigerant. The air, acting as if it is on its own, in this instance, was raising the condenser pressure to 15 bar. This was 1 bar below the high pressure trip out. The higher pressure also causes an increase in electricity consumption.

False Reading of Subcooling

A 30°C false reading of subcooling was recorded because of the air in the system. The dregs of our industry wouldn't know, because they just make up the Tick Sheets while off site!

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Water Chiller Repair Procedure

When our engineer arrived on site to resolve the issue, he started by decanting the refrigerant from the system. Because the refrigerant was contaminated, he sent it back to the suppliers for recycling.

Pressure Test

No refrigerant leak was suspected, but our engineer carried out a nitrogen pressure test as a matter of course. This was passed, so now on to the next phase of the job…


This part of the job rectifies the previous poor repairs. A vacuum was pulled overnight of 2 Torr. This process removed the non condensables and also dehydrated the system.


Half of the new refrigerant was charged into the system, then the remaining refrigerant was charged into the liquid side of the evaporator. This process was carried out until the superheat and subcooling values came to within standard industry guidelines.

System Monitoring

Now that a professional repair had been carried out, the condenser pressure was found to be running at 8 bar. The running amps on the compressor had lowered too.

Energy Monitoring during Water Chiller Repair

The power consumption of the various plant around the building is monitored on the customer’s computer in his facilities office. This is to help identify where electricity is being wasted. He has auditors who assess the efficiency of the building and he has targets to meet. He had already noticed the more efficient running of the chiller subsequent to the repairs. The end user also monitors the energy consumption and worked out the cost saving of the repair over time. The repair would soon pay for itself and then start to save the building money.

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Condenser Cleaning during Water Chiller Repair

The condenser on the other system of the same chiller had recently blocked due to grass pollen. Our engineer brushed it down and chemical cleaned it while on site at no extra cost to the customer.

Pressurisation Unit during Water Chiller Repair

The water system pressure was found to be lower than usual due to a fault that had been reported by the customer. The internal pumps of the pressurisation unit had failed. Therefore, our engineer made a manual top up of the water system to the same pressure as had been recorded on the previous maintenance Tick Sheets. The water system readings were then monitored and were found to be nominal.

Pump Sets

The chillers are fed by a pump set comprising of two pumps. The second pump is a redundant system (N+1) Both pumps are fed from an inverter drive which lowers the electricity consumption of the pumps. There had been an issue reported with the building management system (BMS) so Pump 1 was running in Hand. Our engineer changed the running pump over to Pump 2 which he also left running in Hand. This was to even out the running hours between the two pumps.

Paperwork Time

At the end of the job, our engineer completed a full report on his phone which was uploaded to Head Office in Droylsden, Manchester. He also filled out a Job Sheet with his findings which was duly signed by the customer.

A Service Second to None

Have you had poor repairs carried out? Engineers on site for less time than quoted? Do you have inefficient or poorly running chillers? Look no further than Maximus Chillers! We are expanding in a recession because we provide a service that is second to none!


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


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Maximus Chillers

Maximus Chillers for centrifugal, water cooled, air cooled and ammonia chillers