E07
EHC
Overheat Thermostat Trip / High Limit Fault
Boiler shows E07 and shuts down, often after overheating or poor circulation.
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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
Tripped manual reset overheat thermostat, Blocked primary heat exchanger, Failed pump or airlock, Closed isolation valves on flow/return
How to Fix / Troubleshooting
Safety: Allow the boiler to cool fully before attempting any reset. Isolate power.
User checks:
- Ensure all radiator valves and any isolation valves near the boiler are open.
- Check system pressure is 1.0–1.5 bar when cold; top up if low.
- Press the manual reset button on the overheat thermostat if accessible on your EHC model (refer to user manual). Do not repeatedly reset without finding the cause.
Engineer checks:
- Verify the circulation pump is running and not seized; listen for operation and check current draw.
- Bleed air from the pump and high points in the system.
- Inspect the primary heat exchanger for scale or sludge blockage; flush or replace if restricted.
- Confirm all motorised valves and system valves are open and operating correctly.
Persistent E07 indicates a circulation or heat exchanger issue that must be corrected to avoid damage.
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Repair Difficulty
Hard
4/5
Required Part
Overheat Thermostat
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