BoilerFaultCodesWorcester Bosch A8362 Fault Code
The Worcester Bosch A8362 fault code means: your boiler is struggling to operate because the electrical power reaching it is unstable, insufficient, or the control module has failed to recognize the incoming voltage.. It appears on 1 Worcester Bosch model in our database.
Technical description: Low mains voltage – the voltage may be interrupted, inconsistent or heat control module (HCM) invalid
What causes the Worcester Bosch A8362 fault?
This fault occurs when the boiler's internal electronics detect that the incoming electrical supply is too weak or unstable to safely power the components. It is often caused by a faulty Heat Control Module (HCM) failing to read the voltage correctly, though it can also be triggered by a genuine dip in the property's mains power supply or a failing main circuit board.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
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Gas Safe Register →Worcester Bosch models that show the A8362 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Worcester Bosch A8362 fault code information on this page is sourced and cross-checked against the official Worcester Bosch service / installation manuals for each affected model.
Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 27 April 2026