Which faults are common on Glow-worm boilers?
Glow-worm boilers have been fitted in UK homes for decades, so in Birmingham you will find everything from older CXi and HXi combis to the current Betacom and Energy ranges. The first thing to know is which generation you have, because the same fault shows a different code on old and new models.
Pressure. Low system pressure is the fault Glow-worm describes as the easiest to fix yourself. On current models it shows as F22; on older appliances as F9. Re-pressurising through the filling loop, as your manual shows, usually clears it. If you are topping up often, the system has a leak. See boiler losing pressure.
Ignition. F28 and F29 on current models, or F1 on older ones, mean the boiler could not light or relight. Glow-worm’s own guidance points first to the gas supply, for example a prepayment meter out of credit, and to a frozen or blocked condensate pipe. Top up the meter or thaw the pipe, then reset. See Glow-worm F1 and our frozen condensate pipe guide.
Fan faults on older models. On the CXi and HXi ranges, F2 is a fan fault; on the CI range it covers the fan or the air pressure switch. Before lighting, the boiler checks the fan is clearing flue gases, and refuses to start if it cannot. This always needs an engineer. See Glow-worm F2.
Main board faults. Glow-worm says F61 to F68 indicate an issue in the main board. These need diagnosis by an engineer.
Servicing a Glow-worm boiler
An annual service checks the fan, the electrodes, the condensate trap and the combustion, and most Glow-worm guarantees depend on it. See boiler servicing.
When should you get an engineer?
Glow-worm’s advice is that if a fault code appears and you are unsure, you should contact an installer rather than attempt a fix. We agree. Re-pressurise, check the gas and the condensate pipe, and reset once. If the code returns, or it is a fan, board or lockout code, send an enquiry with the model name and the exact code. A local Gas Safe registered engineer will diagnose it and give a price before any work starts. If your Glow-worm is still within the manufacturer’s guarantee, contact Glow-worm first, as an outside repair may affect it.