BoilerFaultCodesBaxi H:01 .18 Fault Code
Also written as H0118 — same fault.
The Baxi H:01 .18 fault code means: your boiler is failing to move hot water around your radiators or taps, likely because it detects a blockage or a pump issue that prevents it from running safely.. It appears on 8 Baxi models in our database.
Technical description: No circulation of water
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
Find a Gas Safe engineer
Search the official register for a qualified engineer in your area.
Gas Safe Register →Avoid the next call-out bill
A cover plan would handle faults like H:01 .18: no call-out fees, no surprise bills.
Affiliate links. We may earn a commission at no extra cost to you.
Baxi models that show the H:01 .18 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Baxi H:01 .18 fault code information on this page is sourced and cross-checked against the official Baxi service / installation manuals for each affected model.
Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 7 July 2026