Immediate action: Turn off power at the GFCI breaker to prevent heater damage.

Check water level and refilling procedure: Verify that the spa is filled to the correct level. When refilling a Marquis spa, it is best to fill through the filter compartment to help purge air from the plumbing.
Inspect valves and suctions: Ensure all slice valves are fully open and that suction fittings and skimmer are not blocked by debris or ice.
Bleed air thoroughly: Loosen unions at the pump and heater to release trapped air until a steady stream of water appears, then retighten.
Confirm pump operation: With power restored briefly, check that the circulation pump starts and that water is clearly moving. If the pump does not run or only hums, it may need replacement.
Reset and monitor: After correcting the cause, power cycle the spa and monitor closely for any recurrence of dy. If the code returns immediately, shut down and seek professional service.

Warning: Repeated dry firing can permanently damage the heater element and may require replacement of the entire heater assembly.

Display shows dy or DRY and spa shuts down heater shortly after startup.

Possible Causes