Spa will not heat; water stays cold even though pumps run and display appears normal.

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

• Confirm demand for heat: Set the temperature several degrees above current water temperature and verify that the heater indicator icon appears on the display.
• Check for flow: Ensure strong water flow through the heater return; low flow can prevent the heater from energizing.
• Inspect heater connections: Open the equipment bay and locate the stainless-steel heater tube. Check that all electrical connections to the heater terminals are tight and free of corrosion.
• Test heater resistance (advanced): With power off and wires removed from the heater terminals, use a multimeter to measure resistance across the heater element. An open circuit (infinite resistance) indicates a failed element that must be replaced.
• Replace heater assembly: If the element is bad, replace the complete Dynasty Spas heater assembly or element kit as specified for your control pack. Refill, bleed air, and test for leaks and proper heating.