In their most basic sense, water cooled chillers are used to generate cold water. This cold water can be used for cooling in buildings or reducing temperature in production processes for manufacturing facilities. Cooling tower are used in conjunction with water cooling chillers and reject heat from the system. Because of their size and complexity, water cooled screw chiller maintenance is essential for equipment longevity. We have an extensive maintenance checklist for start-up, pre-season inspection and shutdown of water cooled screw chillers. As always, follow your manufacturers recommendations and work with a chiller professional to ensure you don’t miss a step.
Water Cooled Screw Chiller Maintenance Checklist: Start-Up Inspection
- Unit starts
- Record unit running hours
- Document Compressor oil level
- Record oil pump pressure
- Check seal leak rate cc/hr.
- Inspect for rapid cycling
Check oil heater operation - Record return bearing oil temperature
- Record compressor sump oil temperature
- Check oil pump motor amperage
- Visual oil leak-Check
- Check water pressure drop across chiller
- Check water pressure drop across condenser
- Inspect pressure drop across oil filter
- Check pressure drop across refrigerant filter
- Check oil cup levels on open motors
- Inspect refrigerant contamination
- Visual refrigerants leak-Check
- Check chilled water low temperature cutout
- Check refrigerant low temperature cutout
- Inspect safety control press settings
- Check operating controls settings
- Check condenser water temperature differential
- Inspect evaporator water temperature differential
- Record refrigerant temperature
- Document evaporator approaches
- Record condenser approaches
- Check mechanical/electrical interlocks
- Check chilled water flow switch
- Record condenser pressure
- Record evaporator pressure
- Lubricate vane seal oiler
- Check all control module functions
- Inspect electrical connections
- Check nameplate vs. actual volts
- Check nameplate vs. actual amps
- Record time delay on starter switchover
- Check bearing oil discharge temperature
- Check compressor discharge temperature
- List unusual noises/vibrations
- Verify unit operating per requirements
- Check structural integrity of unit
Check oil heater operation Water Cooled Screw Chiller Maintenance Checklist: Pre-Season Inspection
- Unit starts
- Record unit running hours
- Remove oil samples for analysis
- Record compressor oil level
- Check seal leak-rate cc/hr.
- Replace oil filter “0” rings
- Check oil heater operation
- Visual oil leak-Check
- Check oil cup levels on open motors
- Check motor cooling refrigerant filters
- Visual Check refrigerant contamination
- Visual refrigerants leak-Check
- Record condenser pressure
- Record evaporator pressure
- Lubricate vane seal oiler
- Meg test motor and oil pump
- Inspect starter contact surfaces
- Check coupling and alignment
- Clean unloader pot
- Check structural integrity of unit
Unit startsWater Cooled Screw Chiller Maintenance Checklist: Shutdown Inspection
- Unit starts
- Record unit running hours
- Record compressor oil level
- Check seal leak-rate cc/hr.
- Check for rapid cycling
- Inspect oil heater operation
- Visual oil leak-Check
- Check water pressure drop across chiller
- Check water pressure drop across condenser
- Visual Check refrigerant contamination
- Check pressure drop across oil filters
- Check pressure drop across refrigerant filter
- Inspect oil cup levels on open motors
- Visual refrigerants leak-Check
- Record condenser pressure
- Record evaporator pressure
- Check bearing oil discharge temperature
- Check compressor discharge temperature
- Pump down refrigerant charge to receiver
- List unusual noises/vibrations
- Verify unit is operating per requirements
- Check structural integrity of unit
General Chiller Maintenance Tips
We hope the checklists above help you navigate the key steps needed for your water cooled screw chiller maintenance. Some of our general maintenance tips for chiller maintenance include:
- Tube Cleaning – Tubes are the primary path for heat transfer and can have a big impact on the performance.
- Condenser Water Treatment – Untreated water results in higher condenser pressures and less heat transfers. It can also cause inconsistencies in water flow and temperature. Proper chemical treatments keeps the system working correctly.
- Analyze and Change Compressor Oil – Analyzing oil ensures you are changing the oil frequently enough.
- Purge Low Pressure Machines – This involves purging the system of non-condensable gases. This ensure air and moisture are low.
- Analyzing Compressor Water Temp – When possible; increasing the temperature of water being supplied to the facility will improve efficiency.
- Look at Flow Rates – Flow rates should be higher than 3 feet per second and less than 12 feet per second. To slow and you will have flow issues and two high and vibration and noise will create issues.
Pro’s Of Water Cooled Chillers
So why would you choose a water cooled chiller over an air cooled chiller? Some of the pros of water cooling chillers according to an article written by the engineering mindset include:
1. Water cooled chillers are more efficient, especially for large cooling loads. They use the evaporation of water to dissipate heat which is less energy intensive than air cooled chillers. Water also has a higher heat capacity than air so its inherently easier to remove the heat.
2. Water cooled chillers can handle larger loads, for their floor space, compared to air cooled.
3. Water cooled chillers generally last longer because they are inside the building so deteriorate much slower.
Talk With The Chiller Experts
From reciprocating, rotary screw, centrifugal and more, we are your chiller service company. We can resolve issues with capacity controls, refrigerant flow controls and provide all other chiller system services as well. Looking for a new chiller? We sell both air-cooled and water cooled chillers. Give us a call at 1-800-237-3121 or schedule an appointment.
