Display shows dr or DR and spa shuts down heater; may retry several times before locking out.

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

• Step 1 – Verify water level: Fill the spa to the proper level, ensuring all jets are submerged.
• Step 2 – Open all jets: Turn all jet faces fully open to maximize flow during priming.
• Step 3 – Bleed air from pump and heater: Loosen the pump discharge union and, if accessible, the union at the heater inlet until air escapes and water seeps out. Retighten both unions.
• Step 4 – Clean filter: Remove and rinse the filter cartridge. Try running the spa briefly without the filter to see if the dr code clears.
• Step 5 – Power up and monitor: Turn the breaker back on and watch the priming cycle. Listen for the circulation pump; it should run smoothly without loud cavitation noises.

If dr persists and the pump is not moving water, the circulation pump may be failed and should be replaced. Continued operation with a dr condition can permanently damage the heater.