EHC
Lockout without Displayed Code
Boiler starts then shuts down after a few seconds without showing a specific error code.
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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
Intermittent flame detection, Loose sensor connections, PCB relay fault, Unstable gas supply
How to Fix / Troubleshooting
Safety: Intermittent faults can be hazardous if related to combustion. Do not ignore repeated shutdowns.
User checks:
- Observe any pattern (e.g. only on hot water, only when windy) and report to the engineer.
- Ensure gas supply is not being interrupted by other appliances.
Engineer checks:
- Check flame sensor and ignition electrode connections on the EHC boiler.
- Monitor gas pressure during operation for dips or fluctuations.
- Inspect PCB for dry joints or intermittent relays; replace PCB if confirmed faulty.
Accurate diagnosis may require extended observation and use of manufacturer diagnostic modes.
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Repair Difficulty
Hard
4/5
Required Part
Flame Sensor (Ionisation Probe)
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