Safety first: Turn off power at the GFCI breaker. Running the heater without water can permanently damage it.

Verify water level: Fill the spa so that all jets and suctions are submerged and water is at the recommended level on the skimmer.
Open all valves: In the equipment bay, ensure all slice valves on both sides of the pumps and heater are fully pulled up (open).
Bleed air from system: Loosen unions on the circulation pump and heater tube until water flows steadily, then retighten. This removes trapped air that can trigger DR.
Clean filters: Remove and rinse filter cartridges. Try running the spa without filters temporarily to see if DR clears.
Reset spa: Restore power and allow the spa to run its priming cycle. If DR returns, the heater may have been damaged and should be inspected.

If DR persists after proper filling and bleeding, have a technician test the heater element and circulation pump for damage.

Display shows DR or DRY; heater is disabled and spa may run pumps intermittently.

Possible Causes