Display shows dr or DR; heater disabled; spa may run pumps briefly then shut down

Safety: Turn off power at the GFCI breaker before opening the equipment bay.

• Check water level: Fill the spa to the recommended level, typically above all jets and suction fittings.
• Open all valves: Verify that all slice/gate valves near the pumps and heater are fully open (handles pulled up). A closed valve can cause a dry heater condition.
• Remove and clean filters: Take out all filter cartridges and rinse thoroughly. For testing, you can run the spa briefly without filters to see if the dr error clears.
• Bleed air from heater and pumps: Loosen the unions on the heater tube and on the suction side of the circulation and jet pumps until water flows steadily, then retighten. This removes trapped air that can cause a dry heater.
• Reset the spa: Restore power and allow the spa to run through its priming mode. Watch for strong water movement and listen for any cavitation (gurgling) that indicates remaining air.
• Monitor for leaks: After bleeding, inspect around the heater and unions for drips and tighten if necessary.

If dr returns repeatedly with proper water level and good flow, the heater or sensors may be damaged from previous dry firing; have a Bullfrog technician inspect the heater assembly.