0A18 High
Your boiler has detected an unusual and sudden temperature shift and has shut down as a safety precaution to prevent overheating.
Technical description: Flow and return sensor anomaly detected. Sudden temperature change detected on the flow or return sensor.
Typical repair cost: £120-250 (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 0A18 — no call-out fees, no surprises.
*Affiliate links — we may earn a commission at no extra cost to you. Prices shown are starting prices.
Parts commonly replaced
- Flow NTC sensor
- Return NTC sensor
- System pump
*Affiliate links — we may earn a commission at no extra cost to you.