Elecro Pump Interlock / Flow-Dependent Shutdown

Heater repeatedly shuts down with no error code when the pump stops.

Possible Causes

Pump controlled separately from heater with no interlock, Flow switch correctly opening when pump stops, Incorrect user expectation of continuous heating, Timer settings on pump not matched to heater demand

How to Fix / Troubleshooting

Safety first: Never run the heater without the circulation pump operating.

Synchronize controls: Ensure the pool pump timer schedule covers all periods when the heater is expected to run.
Consider interlock: Have an electrician install a control interlock so the heater can only run when the pump is on.
Verify flow switch operation: Confirm that the flow switch opens when the pump stops; this is a safety feature, not a fault.

This behavior is usually normal; adjust pump and heater control strategy rather than bypassing safety devices.

Repair Difficulty

Easy 2/5