E04
Fairland
High Water Temperature Protection
Heater stops and displays E04; unit may start then shut down after a short run.
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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.
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Possible Causes
Thermostat set too high relative to pool volume, Faulty outlet water temperature sensor, Poor water circulation causing localized overheating in titanium heat exchanger, Incorrect plumbing causing short-cycling of hot water back into inlet
How to Fix / Troubleshooting
Safety: Allow the unit to cool before touching any plumbing. Hot water can cause burns.
Steps:
- Check set temperature: On the Fairland controller, reduce the target pool temperature by a few degrees and restart.
- Verify circulation: Ensure all return jets are open and pointing to mix water. Confirm that the heater outlet is not plumbed directly back into the inlet (no tight loop).
- Filter and pump: Clean the filter and confirm the pump is sized correctly and running at the proper speed (for variable-speed pumps, avoid very low RPM when heating).
If E04 continues:
- A technician should test the outlet water temperature sensor and inspect the titanium heat exchanger for scaling or blockage that could cause hot spots.
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Repair Difficulty
Medium
3/5
Required Part
Outlet Water Temperature Sensor
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