Why is chiller maintenance important?
The chiller is the most expensive and most critical cooling unit in a building. A dirty condenser or a wrong amount of refrigerant increases electricity consumption, trips the unit on high pressure alarms and strains the compressor. Regular maintenance catches these problems before a breakdown occurs. We explained how a chiller works in our article what is a chiller.
Chiller maintenance step by step
01Read the logs
From the control panel, record the alarm history, compressor run hours and start counts. Recurring alarms show where to look for the problem.
02Refrigerant circuit measurements
On each circuit, suction and discharge pressure, suction line temperature (superheat) and liquid line temperature (subcooling) are measured. These values show the refrigerant charge, the operation of the expansion valve and the condition of the condenser. The sight glass and filter drier are checked.
03Compressor and electrical
Compressor currents and phase balance are measured, terminal connections are tightened and contactors are checked. On screw compressors, the oil level, oil pressure and oil heater are checked; an oil analysis is done when necessary.
04Condenser
On air-cooled chillers, the condenser coil is cleaned with a suitable method, and fan motors and blades are checked. On water-cooled chillers, the condenser approach temperature is monitored; if it has risen, tube cleaning is planned and the cooling tower water is checked.
05Water side
Evaporator inlet and outlet water temperatures and the difference are measured, the flow switch is tested and strainers are cleaned. Low flow is the most common cause of a freeze alarm. You can check the flow with the chiller flow calculator.
06Safety and control
High and low pressure switches, freeze protection, sensors and setpoints are checked.
07Report
All measurements are recorded per unit and compared with the previous maintenance. You can use the free chiller maintenance form.
Let us plan your chiller maintenance
Send us the chiller brand, model and capacity; we will prepare a maintenance plan and a written quote.
How often is chiller maintenance done?
| Interval | Tasks |
|---|---|
| Weekly / monthly (operation) | Alarm check, water temperatures, visual leak and sound check |
| Start of season | Comprehensive maintenance, condenser cleaning, measurements, commissioning |
| During the season | Interim checks and measurements |
| End of season / before winter | Freeze protection: glycol ratio or draining |
For process chillers that run all year, the intervals are shorter. For winter preparation, see our article preparing a chiller for winter.
What can facility staff do, and what should they not do?
Regularly monitoring the water temperatures, the alarm screen and the area around the unit is the facility staff's job. Work on the refrigerant circuit, refrigerant handling and electrical panel work should be done by a qualified technical team. For our service scope, see our chiller maintenance page.
Frequently asked questions
How long does chiller maintenance take?
It varies with the size of the unit, the number of compressors and circuits, and the scope of condenser cleaning; a small chiller can be done in a few hours, while large facilities may take one or several days.
Is refrigerant added during chiller maintenance?
Only if the measurements show low refrigerant, and after the leak has been found and fixed. Adding refrigerant without finding the leak only postpones the problem.
How is a chiller condenser cleaned?
On air-cooled types, with suitable pressure and cleaner that will not damage the coil; on water-cooled types, with mechanical or chemical cleaning of the tubes.
How often should chiller maintenance be done?
For comfort applications, a comprehensive maintenance at the start of the season and interim checks during the season are usually recommended; for process chillers, the interval shortens according to operating hours.