Heater shuts down during operation; display shows SPH2

Safety: Overheated exhaust can indicate dangerous combustion issues. Turn off the heater and allow it to cool before inspection.

• Check exhaust outlet: Make sure the SmartPool heater vent cap or stack is not blocked by nests, leaves, or debris. For indoor installations, verify the venting system is intact and not crushed or disconnected.
• Clear intake openings: Ensure cabinet louvers and intake grilles are unobstructed so the heater can draw enough combustion air.
• Inspect flue sensor wiring: With power off, locate the flue temperature sensor on the exhaust collector. Check that its wires are intact and firmly connected to the control board.
• Reset and test: Restore power and call for heat. If SPH2 returns quickly, stop using the heater. A technician should check for scale in the SmartPool heat exchanger and verify combustion.