Author Archives: Maximus Chillers

Water Chiller Maintenance

Water Chiller Maintenance

Maximus chillers provide maintenance to a wide range of water chillers. Some of which have kilowatt hour meters fitted. This means we can monitor the reduction in energy consumption, directly as a result of our maintenance being carried out

Efficient Water Chiller Maintenance

Maintenance is carried out to ensure every aspect of your water chiller is running efficiently. We believe our Tick Sheet is the best in the industry. It looks in detail at the running conditions of the plant, component adjustments and the parameters in the controls. The Tick Sheet is used to assess if there are problems that are starting to occur before a safety shutdown happens. Below are some of the issues that we keep on top of to increase the efficiency of your plant

Shell and Tube Insulation

The build up of dirt acts as an insulator in shell and tube heat exchangers. These are used for the evaporation and the condensing of the refrigerant

The evaporator

In the evaporator, should the tubes be fouled, there will be a reduction in heat absorbed into the system. This will cause the plant to stay on longer and use considerably more energy. Should the tubes become considerably fouled, the water chiller will malfunction and eventually system shutdown will occur

The Condenser

In a shell and tube condenser, the reverse of the above will occur. Tube fouling, acting as an insulator, will prohibit the rejection of heat from the system. The head pressure control will open the condenser controls to try and assist in heat rejection. Heavy fouling will cause an increase in the consumption of energy. Eventually a safety shutdown will occur causing loss of production

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Compressor Loading

Should the loading of the compressors be found to be faulty. The plant will not be able to effectively match the load

Over Loading

Too much loading may occur, causing the water chillers to achieve set point too quickly. The plant will then go through the off cycle. This means that the plant will have to load back up, using more energy than matching the load continuously

Under Loading

Should the plant be unable to load up to the required level to match the load, this will cause the water temperature to creep up and the lag chillers being called for to match the load. More water chillers running than necessary dramatically increases energy consumption

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Industrial Process Chiller Service and Maintenance

Industrial Process Chiller Service and Maintenance

Maximus Chillers recently carried out service & maintenance to an Italian chiller

Service and Maintenance of the Water Level Sensor for the Industrial Process Chiller

The industrial process chiller has a water treatment schedule, but on this visit, the water level sensor needed service and maintenance. This is because the three prongs of the sensor were not completing continuity. The prongs complete the continuity from the wire going into the sensor, along the prong, then to another wire completing continuity back to the controls of the chiller

Low Water Prong

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

Correct Level Prong

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

High Water Level Prong

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

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Service and Maintenance Visit to the Industrial Process Chiller

As we were already on site to carry out the service and maintenance of the industrial process chiller, so 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 prongs. 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

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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

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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 


Industrial Refrigeration Ammonia Service Cat Ladder

Industrial Refrigeration Ammonia Service

Industrial Refrigeration Ammonia Service Visit

The industrial refrigeration ammonia service visit was in Aberystwyth. We look after 2 ammonia chillers on site. They are 10 year old chillers that have been designed to need ongoing service. Quite easy job as the faults they go into are reoccurring round in a circle. They have previously had the same problems

Shaft Seal for Industrial Refrigeration Ammonia Service

The industrial refrigeration shaft seal had started to leak so ammonia service was arranged. It was fitted by removing the shaft seal cover, splitting the coupling and sliding the shaft seal over the shaft. After removing the non condensables, we reintroduced the ammonia back into the compressor. The 'o' rings leaked

Ammonia Service of Leaking Industrial Refrigeration 'O' Rings

The ammonia service of industrial refrigeration ‘o’ rings occurs because they become flattened and plastic like. This is caused by heat around the high side of the screw compressor. When there is pressure in the system- the oil if forced against the gap- making a seal. After the ammonia refrigerant had been handled- the oil ran away- causing the leak when the ammonia was reintroduced

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Lift and Shift for Ammonia Service Visit

Before the ammonia service visit, the compressor had been removed of it’s pipework and ancillaries. The lift and shift guys arrived and set up their lifting equipment. They raised the compressor and manoeuvred it on to a trolley. They used a stair walker to get it up and down the steps. They used a winch to get the compressor, end on- down a cat ladder

Tear Down of the Ammonia Screw Compressor

It is always better to tear down this kind of compressor in a workshop- on a bench with compressed air and all the tools nearby. We unbolted the castings and slid the screw out. The various castings being laid out in a line. We replaced the ‘o’ rings for new the rebuilt the compressor

Ammonia Refrigerant Charging
Ammonia Refrigerant Charging

Ammonia Refrigerant Service Charge

Part of the ammonia refrigerant had been handled during the service visit. This left the compressor pipework, compressor and the oil separator open to atmosphere. The non condensables were evacuated. In the photo we are lifting the cylinder up a cat ladder into the plant room. From there it needed to be man handled up some steps, down some steps and out onto the roof. We charged the ammonia plant with liquid ammonia until the superheat and subcooling values were within industry known limits. The sight glass levels and condition were monitored too

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Chilled Water System Repair

Chilled Water System Repair of Condenser

Chilled Water System Condenser Beyond Repair

The condenser on the chilled water system had been deemed to be beyond repair by the customer. The previous company had been chasing leaks round in a circle so the customer had decided to buy a new condenser. This was our first job with a new Maintenance Contract so we wanted to make a good impression

Condenser Removal on the Chilled Water System

There was no refrigerant in the chilled water system so our engineer cut the discharge and liquid line to the condenser. He then drilled out the rivets so the frame could be taken apart. Lifting shackles were fitted to the old condenser to aid the removal. Then, slings were fitted and a forklift truck removed the old condenser

Condenser Replacement on the Chilled Water System

Our engineer supervised the condenser replacement on the chilled water system. He found that the new condenser did not fit correctly. The new condenser was 5mm thicker than the old one. It was decided to lift it back out and angle grind the frame to make more room. Once this was completed, the new condenser fitted correctly and was bolted in place

Chilled Water System Pipework Repair

The pipework had to be repaired and brazed in on the chilled water system. Then, the standard practice of a pressure test to ensure the integrity of the system

The Evacuation Process

Having passed the pressure test, our engineer set up the vac pump and started the evacuation process. This is to dehydrate the system by pulling a vacuum of less than 2 Torr. Any moisture in the system will boil away and leave the system dry

Recharge and Test Operation

The refrigerant is R410a. Our engineer put around half the charge in, then trimmed the remaining charge according to the superheat and subcooling values. He monitored the chilled water system for the rest of the day. He was looking for leaks as the plant was at operating pressures of 30 Bar. All was well, so the customer signed off the paperwork as he was pleased with the efficient professionalism of our engineer

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


Chilled Water System Service near Saint Basil's Cathedral

Global Chilled Water System Service

Moscow Visit

Always good to get out of the country to carry out chilled water system service around the globe. Just had a little free time this visit to see Red Square and Saint Basil's Cathedral. Most of the visit was bogged down resolving issues

Electrical Problems

One of the water cooled chillers was pumping down due to electrical problems. One of the solenoids for the evaporator was not opening. All checked out okay with the solenoid coil and valve. Following the wiring diagram lead to the relay board. The relay board is responsible to run various components around the compressor. It was not obviously blown and there were no dry soldered joints on the back. I decided to tighten up the wiring and unplug, then plug all the connectors back in. When I ran the chiller again the problem went away

Chilled Water System Global Service

As we provide a global service for chilled water systems: we cannot get back the day after leaving site. Therefore, after resolving the above issue, I ran the system in local with some of the other systems off to prove it. All was okay. After completing the rest of the service on the chillers I put the whole of the plant back in Auto to prove it all together

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Flow Switch Failure During Global Chilled Water System Service

The flow switch failed in one of the most remote plant rooms in the globe for chilled water system service. This is due to security issues. As one of the service checks- I tried to trip the chiller on flow fail. The chiller did not stop. I didn't want to valve off the water system repeatedly as the air handlers are old and 'dead heading' could cause failure. Instead I decided to use the Hand/ Off/ Auto switch for the pump. There are two adjusting screws on the flow switch. After several attempts I got it to settle down, then carried out tests to make sure it would not happen again

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Chilled Water System Flow Switch Maintenance

Chilled Water System Maintenance

Maintenance of the Chilled Water System Flow Switch

The chilled water system flow switch requires regular maintenance due to a to build up of contaminants on the sensor. Over time, slime accumulates giving false readings. The problem is relatively easy to sort out: a wipe with a cloth

Retrieving the sensor

The more difficult part is deciding how the retrieve the sensor. It is fixed with a bolt into the chilled water system being maintained. Therefore there is pressure inside. The textbook way to do the job is to valve off the section of pipework, then drain the glycol into a vessel. There are other ways known to an engineer

Snatching the Flow Switch!

Although not text book: snatching the flow switch is a considerably easier way of maintaining the chilled water system! One of our seasoned engineers unscrewed the bolt whilst holding the flow switch in. He whipped it out- gave it a quick wipe and stuck it back in! Only a small amount of the secondary coolant was lost (which shot out- loosing no height) He re-tightened the bolt and the job was done

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Checking the Fault Out Level

As you can see from the picture: there is a green light on 0. This indicates that the pump is off. Not to be confused with pressure, as there will be a couple of bar on a roof an 6 bar or so in a basement. The higher pressure in a basement is due to the head of water pushing down. With the pump on: the green lights go all the way up to 9 with the fault out level showing red on 7

Maintaining the Chilled Water System Fault Out Level

Maintaining the chilled water system flow switch can be achieved with a terminal driver. Using the manual that comes with the flow switch: the buttons can pressed a number of times to 'self test' Also, the fault out level can be set

Testing the Flow Switch

As part of the maintenance, the flow switch is manually tested using one of two methods. This ensures that the switch will function correctly when it needs to

Read more about flow measurement on Wikipedia


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