Topside control panel displays “dr” and spa will not heat; circulation pump may run briefly then stop.

Safety first: Turn off power at the GFCI breaker before opening any equipment compartment or touching wiring.

• Check water level: Ensure the water level is above all jets and at the recommended fill line. Top off if low.
• Clean or swap filters: Remove the Caldera filter cartridge(s). Rinse thoroughly with a garden hose from inside out. For testing, run the spa briefly without the filter (never long-term) to see if the error clears.
• Bleed air from system: After refilling, loosen the union on the E5 circulation pump or heater inlet slightly until water seeps out, then retighten to remove trapped air.
• Reset power: Turn the GFCI breaker off for 30 seconds, then back on. Watch if the circulation pump runs steadily and the “dr” code clears.
• If problem persists: Inspect the E5 circulation pump for vibration or noise. If the pump is hot, silent, or seized, it may have failed and should be replaced. Also inspect heater unions and suction fittings for leaks drawing in air.

If you smell burning, see melted plastic, or the breaker trips repeatedly, stop and contact a qualified spa technician.