D.27 High
Your boiler's internal control board is having trouble communicating with an add-on electrical component that manages your external pumps or heating zones.
Technical description: Switching accessory relay 1
Typical repair cost: £180-450 (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.27 — no call-out fees, no surprises.
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Parts commonly replaced
- Main Printed Circuit Board (PCB)
- VR40 Multi-functional Module
- Wiring Harness
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