E25 High
Your boiler has detected that the water inside the main heating unit has frozen due to extremely cold temperatures, preventing it from operating.
Technical description: Main heat exchanger frozen
Typical repair cost: £80-160 (including labour)
DIY fix possible
Check if any external condensate pipes are frozen and thaw them with warm (not boiling) water.Increase the room thermostat setting to encourage movement in the system.Ensure the boiler is located in a draft-free area and keep the heating on a low constant setting during cold snaps.Reset the boiler once the unit has thawed out.
Protect yourself from future repair bills
A boiler cover plan would cover faults like E25 — no call-out fees, no surprises.
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Parts commonly replaced
- Condensate pipe insulation
- Trace heating cable
- Main heat exchanger
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