Display shows Htr ERR or HEATER ERROR; spa does not heat.

Safety first: Turn off power at the GFCI breaker and verify with a non-contact tester before touching heater wiring.

• Step 1 – Visual inspection: Open the equipment bay and inspect the heater tube and terminals on the Nordic control pack. Look for burned wires or discoloration.
• Step 2 – Check heater connections: Ensure heater terminal screws are tight and there is no corrosion. Do not overtighten.
• Step 3 – Test heater element: With power off and wires removed from the heater terminals, measure resistance across the heater element with a multimeter. An open circuit indicates a failed heater.
• Step 4 – Inspect high-limit: Verify the high-limit sensor is properly attached and not tripped (some models have a manual reset button on the heater housing).
• Step 5 – Replace heater: If the element is open or leaking, replace the heater assembly with a Nordic-compatible heater tube and element.
• Step 6 – Suspect control board: If the heater tests good but never receives power when heat is called, the heater relay on the control board may be faulty and the board may need replacement.