Spa will not heat; water stays cold even though pumps run and set temperature is higher than actual

Safety: Turn off power at the GFCI breaker and verify no voltage before testing the heater.

• Check spa mode and setpoint: Ensure the spa is in standard or ready mode and the set temperature is above current water temperature.
• Verify heating indicator: On the topside, confirm that the heat icon appears when the spa calls for heat.
• Inspect heater connections: In the equipment bay, check that heater wires are tight and not burned at the control pack and heater terminals.
• Test heater element (advanced): With power OFF and wires removed from the heater, use a multimeter to measure resistance across the heater terminals. An open circuit indicates a failed element.
• Check for ground fault: Measure resistance from each heater terminal to ground; a low reading indicates a shorted element that must be replaced.

If the heater tests good but does not receive power when heating is called, the control board relay is likely faulty and the control pack may need replacement.