Checks to Perform When a Chiller Alarm Occurs
A chiller alarm is more than a message interrupting production: it signals a condition that needs assessment. The right approach is to establish safety, record the alarm and avoid repeatedly restarting equipment before the cause is understood.
1. Assess safety first
If there is smoke, a burning smell, sparking, severe vibration, water reaching electrical equipment or suspected refrigerant leakage, stop routine checks. Leave the hazardous area, restrict access and follow the site emergency procedure. Trained personnel should use the designated emergency shutdown procedure only if it is safe to do so.
Stopping from the control panel does not provide safe energy isolation for maintenance. Opening panels, removing guards or working on electrical or pressurized circuits is for authorized personnel. Before maintenance, relevant energy sources and stored energy must be made safe under the site lockout/tagout procedure.
2. Record information before clearing the alarm
Record the alarm code and complete message, time, affected circuit and alarm history. Photograph the display from a safe position. Distinguishing the first alarm from subsequent warnings helps the service team assess the event.
Where available, note displayed entering/leaving water temperatures, setpoint, flow and pressure; do not open covers to take measurements. Include recent power interruptions, maintenance, valve changes or production load changes. The same alarm code can mean different things on different controllers.
3. Low flow or flow alarm
Check the displayed pump running/fault status, any flow indication and externally visible leaks. On systems with a tank, observe its level indicator. Only observe the position of labelled valves; do not change unverified valve positions.
A running pump indication does not prove adequate flow. A blocked strainer, air in the circuit or pump/valve problems are possible causes. Opening a strainer or venting a circuit requires a service procedure. Never bridge a flow switch or force cooling operation before circulation is confirmed.
4. High pressure alarm
For air-cooled units, observe obstructions at air inlets/outlets, visible coil fouling and possible recirculation of hot discharge air from a safe distance. For water-cooled units, record the displayed condenser water circuit status.
These observations narrow the possibilities but do not establish a diagnosis. Fan operation must be assessed in the context of the operating mode. Keep clear of fan guards, do not adjust pressure switches and never release refrigerant. Cleaning and refrigeration circuit checks belong to authorized service personnel.
5. Low pressure or frost protection alarm
Record water temperatures and indicated flow; report unusual icing visible from outside. Low pressure does not automatically mean a low refrigerant charge. Heat load, water circulation, refrigerant feed and sensor condition must be assessed together.
Do not force a restart after a freeze alarm or use a flame or uncontrolled heat to remove ice. Technical personnel should verify glycol type/concentration, setpoint and frost protection. Indiscriminately disconnecting main power in cold weather can disable pumps and frost protection; where no immediate danger exists, follow the unit shutdown instructions.
6. Compressor, pump, fan or electrical alarm
For overcurrent, overload, phase or drive warnings, record the full message and affected equipment. Check operating records for recent power interruptions or supply issues.
Do not open the electrical panel, alter wiring, swap phases or repeatedly reset tripped protection. Current/voltage measurements, connection checks and motor assessment require authorized personnel with suitable training and equipment. Never raise an alarm threshold to keep equipment running.
7. Temperature, sensor and communication warnings
Compare and record the setpoint and displayed entering/leaving temperatures. A sudden load increase, warmer process return or recently changed settings can help explain the event. An unusual reading may reflect an actual process condition or a measurement problem.
Do not interfere with connections following sensor or communication alarms. Disabling a sensor, substituting a resistor or randomly changing settings is not a safe solution. Service personnel should verify measurement and communication status against the unit documentation.
8. When should an alarm be reset?
Acknowledging an alarm, correcting its cause and restarting are separate actions. Some warnings clear automatically; others require service checks. Only after the cause has been corrected, safe conditions confirmed and the unit manual or authorized service permits it should an authorized operator follow the specified restart procedure.
If the same alarm returns, stop repeated attempts. Monitor operating readings and the process after an approved restart. Power cycling to hide an alarm does not fix the cause and may remove information needed for diagnosis.
9. What should be sent to technical service?
- Unit model, serial number and installation location
- Alarm code, complete message, time and recurrence frequency
- Display and equipment photographs taken from a safe position
- Available displayed temperatures, flow and pressures, including units
- Maintenance, power interruptions or process changes before the alarm
- Actions already taken and the result of any reset
Contact CEMS Chiller technical support with this information. Intervention is coordinated with our contracted technical services in Türkiye and abroad according to the needs and site conditions, with remote support where appropriate. Also follow the facility’s safe shutdown plan for production equipment affected by the loss of cooling.
This article is general operator guidance, not a fault diagnosis or repair procedure. The unit’s own manual and authorized service instructions govern alarm codes, operating limits and restart conditions. Settings for other manufacturers and models in the references must not be applied to CEMS units.
