D.26 High
Your boiler's internal control board is unable to communicate with an optional secondary accessory or pump, causing the system to stop running as a safety precaution.
Technical description: Additional relay control ecoTec
Typical repair cost: £180-350 (including labour)
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
Protect yourself from future repair bills
A boiler cover plan would cover faults like D.26 — no call-out fees, no surprises.
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Parts commonly replaced
- Main PCB
- Additional Relay Module
- Wiring Harness
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