BoilerFaultCodesWhat the manual says
Manufacturer manualMain PCB / Display PCB fault
From this model's manual
Verified against the Glow Worm/Glow Worm Ultracom 35 Store 4701915 installation & service manual.
What causes this fault?
This fault occurs when the boiler's internal computer chips fail to recognize or communicate with each other, often due to a hardware malfunction or a breakdown in the electronic circuitry. The most common reason is a voltage surge or general component wear that scrambles the software, preventing the boiler from performing its safety checks.
Engineer required
This is a high severity fault. Stop using the boiler and call a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
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Related fault codes
All 70 fault codes on the Ultracom 35 Store
Seeing a different code? Every code this model can display, in one place.