Home/Boiler Fault Codes/Worcester Bosch A1
WORCESTER BOSCH FAULT CODE
Worcester Bosch A1
Typically points to a pump fault — the pump may be stuck, running dry, or affected by air trapped in the system, and is often linked to low system pressure.
WHAT A1 TYPICALLY INDICATES
Typically points to a pump fault — the pump may be stuck, running dry, or affected by air trapped in the system, and is often linked to low system pressure.
WHAT TO DO
Checking and, if low, topping up system pressure via the filling loop is a reasonable first check. If the code returns after that, This is not a DIY fix — it requires a Gas Safe registered engineer to diagnose and repair safely.
A NOTE ON GAS SAFE REGISTRATION
Any work on the gas side of a boiler in the UK legally requires a Gas Safe registered engineer, it isn't optional. Our engineers are fully Gas Safe registered, and you're always welcome to ask to see ID on the day. This page is general information about what a fault code typically indicates; it is not a substitute for an engineer diagnosing your specific boiler.
Seeing Worcester Bosch A1 on your boiler?
Tell us the code and your postcode. A fully Gas Safe registered engineer will diagnose the actual cause before quoting a fix.
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