Heater runs but occasionally shuts down when the pump speed is reduced (variable-speed pump).

Safety first: Do not operate the heater with inadequate flow; heat exchanger damage can occur.

• Increase pump speed: Program the variable-speed pump to run at or above the minimum RPM recommended by AstralPool when the heater is on.
• Adjust bypass: If a bypass is installed, partially close it to send more water through the heater while maintaining overall system flow.
• Monitor pressure: Check filter pressure and ensure it is within normal operating range; clean filter if high.

If shutdowns continue, a technician may need to verify actual flow rate and adjust system design.