Air Cooled Screw Chiller Maintenance

Two green screw compressors being maintained in an air cooled chiller

Air Cooled Screw Chiller Maintenance

We recently carried out air cooled screw chiller maintenance at a site we look after in the North West. The plant is described such because it uses two Bitzer screw compressors to create a pressure difference in the R134a refrigerant. The plant has been designed to be remotely operated…

Chiller Remote

This is a way of operating the chiller remotely. Instead of the end user having to walk up to the machine each day to check for faults (chiller local) the plant can be remotely operated and monitored.

Run Signal

The run signal to start the chiller is sent by a relay being energised in the BMS panel (Building Management System) in the plant room. When the chiller receives the run signal, it shows the chiller on message.

Fault Feedback

When the chiller develops a fault, the chiller energises a relay, sending a fault feedback signal to the BMS panel. This fault signal causes the run signal to drop out and a new run signal to be sent to the adjacent redundant system.

BMS Panel

The BMS panel runs contactors which bring the water system pumps on, it also receives analogue signals from temperature sensors on the water system. These inputs and outputs are wired into a PCB which converts them into a data signal. This signal is sent down a CAT 5 plug cable to the supervisor in the facilities management room in the building below.

Remote Monitoring During Air Cooled Screw Chiller Maintenance

A supervisor is a computer which has graphic monitoring of the chillers and the air handlers. The supervisor, is connected down a phone line to the BMS company. Often, the chiller is remotely operated and monitored from a laptop used by a BMS engineer working from home.

0161 370 7193

service@maximuschillers.com

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Air Cooled Screw Chiller Maintenance Parts

With a comprehensive range of chiller parts available, off the shelf, for air cooled chillers- look no further than Maximus Chillers for all your chiller parts. We can also supply parts mostly same day. A specialist part on this chiller is the electronic expansion valve driver- this regulates the steps in the expansion valve to ensure correct superheat in the shell and tube evaporator. An electronic expansion valve driver is also available to regulate the expansion valve in the refrigerant economiser. This acts to subcool the refrigerant to ensure optimum system efficiency.

Diagnosis During Air Cooled Screw Chiller Maintenance

Should you need chiller diagnosis- one of our trained professionals onsite during the maintenance will identify the issue with his system test equipment.

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

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Read more about remote monitoring and control on Wikipedia | Click Here


Global 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 global chilled water system service. 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.

0161 370 7193

service@maximuschillers.com

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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.  The chiller did not stop when a test was carried out. I didn't want to valve off the water system 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. After several attempts of trimming I got the switch to settle down, then carried out tests to make sure it would not happen again.

Related Blogs:
Chilling Plant Service

Chilled Water System EEV Service

Water System Service of Evaporator

Chiller Service of Fan Decks

Process Chiller Service

HFC Chiller Service

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