E4
MSPA
Water Over-Temperature Shutdown
Display shows E4 and heating stops; spa may shut down for safety.
Advertisements
Safety Warning
This repair may involve working with high voltage components or water connections. Always unplug the appliance before removing any panels.
If you are not confident in your ability to perform this repair safely, we strongly recommend contacting a professional technician.
Advertisements
Possible Causes
Thermostat set too high in hot ambient conditions, Stuck heater relay on MSPA control PCB, Faulty temperature sensor reading too low, Poor water circulation causing localized overheating
How to Fix / Troubleshooting
Safety first: If water feels excessively hot, keep users out of the spa. Unplug the unit and allow water to cool.
- Confirm actual water temperature: Use an independent pool/spa thermometer to compare with the MSPA display. If the display is much lower than actual, the sensor is misreading.
- Reduce set temperature: Once cooled, power the spa and set the temperature to a moderate level (e.g., 36–38°C). Monitor whether E4 reappears.
- Improve circulation: Clean the filter cartridge and ensure no blockages at suction/return. Run filtration mode for at least 15–20 minutes before enabling the heater.
- Inspect sensor and wiring: Check the main NTC temperature sensor on the heater housing and its cable. Replace the MSPA heater NTC sensor if it reads incorrectly compared to a thermometer.
- Control board suspicion: If the heater continues to run even when the set temperature is reached (water keeps getting hotter), the heater relay on the control PCB may be stuck closed. This is a high‑risk condition and should be addressed by a qualified technician; the control PCB may need replacement.
Advertisements
Repair Difficulty
Hard
4/5
Required Part
MSPA Main Control PCB
Check Price on Amazon
We may earn a commission from links on this page.
Advertisements