Even when your chiller is inspected and maintained regularly, its performance can degrade or deteriorate over time. Pumps can fail, process lines can clog, refrigerant can leak, and any number of problems associated with component aging or changing environmental conditions can occur (table 1).

Following are some initial steps to take to help isolate the problem:

  • Make sure that the chiller is running. A blown circuit breaker or fuse, loose wiring, or simply a power switch that’s been put in the “off” position might be preventing the chiller from running.
  • Determine whether the chiller is cooling. Check the temperature of the coolant at the chiller’s outlet to the process. If it isn’t at or near the setpoint temperature, the evaporator might be iced up or the heat transfer properties of the coolant fluid might be deteriorating.
  • Confirm that the pump is running. A closed or partially closed valve, failed pump, inadequate coolant volume or process line restriction might be preventing the adequate flow of liquid through the process coolant loop.
  • Check the process and environmental conditions. The load on the chiller might be too great due to changes in the process or the ambient temperature. Other conditions that can affect the chiller’s heat removal capabilities include a change in the location of the chiller (near other heat-generating equipment or farther from the process equipment); loose, damaged, or missing insulation on the piping between the chiller and the process; or fluctuations in line voltage.

Common Chiller Problems and Possible Causes

1. CHILLER DOES NOT POWER UP

  • Improper line voltage or loose connection
  • Incorrect phase connection (three-phase units)
  • Blown circuit breaker or fuse
  • Power switch in "off" position

2. NO PUMPING OR INSUFFICIENT FLUID FLOW

  • Improper or fluctuating line voltage
  • Insufficient fluid in reservoir
  • Pinched or restricted process line
  • Close or partially closed process valve
  • Coolant fluid unsuitable for temperature requirements
  • Blocked fluid filter
  • Process piping too small
  • Process restriction
  • Pump failure

3. NO COOLING OR INSUFFICIENT COOLING

  • Improper or fluctuating line voltage
  • Clogged air filter or condenser
  • Coolant fluid unsuitable for temperature requirements
  • Heat transfer properties of the coolant fluid have deteriorated
  • Refrigerant leak
  • High ambient temperature
  • Evaporator iced up