SYMPTOMS
System or tank re-circulation pumps starts and run. After operating for a varied amount of time, pumps turn off.
CAUSE
Between the main power buss, where power comes into the chiller, and the pump motor there will typically be several places in the electrical circuit where power can be interrupted. These are: Wires, fuses, motor starters and internal motor winding protectors. Any of these can cause a pump shutdown.
RESOLUTION
Before starting any troubleshooting ALWAYS TURN THE POWER OFF FIRST!. With power off at the chiller main service disconnect, perform the following checks:
1.Check (tighten as needed) all wire connections between the main power buss and pump.
2.Make a note of the pumps SF amps indicated on the pump motors nomenclature sticker. If your chiller is equipped with a motor starter, make sure the amp setting on the motor starters overload adjustment is set to match the pumps SP amps. If it is not, lift the plastic dust cover and adjust using the proper sized screwdriver.
3. Restart the chiller and pump(s).
4. Using an amp clamp, check the running amp draw pump(s). If the running amp draw is greater than SF amps, reduce fluid flow through the pump until your running amp draw is at or below SP amps.
5. Make sure your pump(s) are turning the correct direction.