Spa does not heat; water stays at ambient temperature even though pumps run normally.

Shock hazard: Turn off power at the breaker before testing heater circuits.

• Confirm settings: Ensure the set temperature is higher than current water temperature and that the spa is not in Economy or Sleep mode.
• Check heater indicator: When calling for heat, verify that the heater icon appears on the Hanscraft display. If not, a sensor or logic issue may be preventing heat.
• Test heater resistance: With power OFF and heater wires disconnected, measure resistance across the heater terminals. Infinite resistance indicates a failed element that must be replaced.

If the heater tests good but there is still no heat, the control board’s heater relay or sensor inputs may be faulty and require professional service.