BoilerFaultCodesYour boiler's internal computer brain is either faulty or has been replaced with the wrong software version for your specific model.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Incorrect PCB Fitted
What causes this fault?
This fault occurs when the boiler's main control board fails to recognise the hardware it is connected to, often due to a communication breakdown between internal components. It most commonly happens if a replacement part has been installed without being correctly programmed, or if the chip that stores your boiler's specific identity has become corrupted or loose.
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 →Protect yourself from future repair bills
A boiler cover plan would cover faults like E28 — no call-out fees, no surprises.
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Potterton Promax Combi HE Plus is discontinued — time for a new one?
Parts for discontinued models can be hard to find and expensive. A new A-rated boiler could save you money on both repairs and energy bills.
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