FO30 High
Your boiler has stopped working because it cannot detect any water flowing through the system, meaning it cannot safely heat your home or water.
Technical description: Sensor S3 fault
Typical repair cost: £120-£200 (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 FO30 — no call-out fees, no surprises.
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Parts commonly replaced
- Flow sensor (S3)
- Wiring harness
- Main PCB
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