Display shows OH or OHH and spa shuts down with pumps off; water feels very hot

Critical safety: Overheat can damage equipment and cause scalding. Turn OFF power at the GFCI breaker immediately and allow the water to cool with the cover open.

• Remove the cover: Open the spa cover to allow heat to escape. Do not use the spa until the OH code is cleared and the cause is corrected.
• Check water level: Ensure water level is above all skimmer openings and filter housings. Low water can starve the circulation pump.
• Clean or remove filters: Remove all Michael Phelps Spas filter cartridges. Rinse thoroughly with a garden hose from inside out. For testing, run the spa briefly with filters removed once power is restored.
• Bleed air from pumps: With power OFF, loosen the pump union on the circulation pump and primary jet pump just enough to let trapped air escape until water seeps out, then retighten.
• Inspect circulation pump: Verify the circ pump (if equipped) spins freely and is not blocked. Check for vibration or noise indicating a failing pump.
• Restore power and test flow: Turn the breaker ON. Run the pumps on high speed and confirm strong flow from all therapy jets and any dedicated circulation outlets.
• Monitor temperature: Set the temperature a few degrees lower and watch the display. If OH returns quickly, shut power OFF again.
• Check for stuck heater relay (advanced): If the heater indicator on the topside stays on even when the set temperature is reached, the heater relay on the control board may be stuck closed. This requires control pack repair or replacement by a technician.

If OH persists after filter cleaning, air bleeding, and verifying pump operation, contact a qualified spa technician to check heater control and sensor calibration.