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Glow-worm Betacom Fault Codes

The Glow-worm Betacom (and later Betacom⁴) was the brand's budget compact combi — a small, simple, keenly priced boiler installed in great numbers in flats, rentals and starter homes through the 2010s. It uses a compact F-code set on a simple display: low single-digit and low-double-digit F-numbers covering ignition failure, flame loss, fan and sensor faults, overheat and pressure. Most Betacoms are now into double-digit ages, and their diagnostic context is that of a hard-working budget veteran: the faults that arrive are wear faults, parts remain cheap and available, and the repair-or-replace question deserves honest arithmetic once bills approach the boiler's value. The codes below link to their full pages — exact meanings can vary between Betacom generations, so treat the linked page (and your model's manual) as authoritative for your boiler year.

Where Betacom fault codes appear

The Betacom has a small, simple display (with indicator LEDs on some versions) showing an F-prefixed code on faults. On the oldest examples the display is terse — note exactly what shows, and your boiler's specific model (Betacom 24, 30, Betacom⁴ etc.) helps any engineer date the code scheme.

Resetting a Glow-worm Betacom

Press the reset button and hold briefly; the boiler retries. Pressure faults want the system topped up to about 1–1.5 bar via the filling loop first. On a boiler of this age and class, a code that returns after one reset has earned a proper diagnosis — and if quotes mount, an honest conversation about replacement.

Common Betacom problems

Ageing Betacoms mostly present ignition lockouts (electrodes and gas-valve wear, plus the universal winter condensate freeze), pressure loss on tired sealed systems, and fan and thermistor failures of honest old age. None of it is exotic; the judgement call is economic. A well-serviced Betacom can soldier on cheaply — an unserviced one at 15 years is usually telling you something.

Most common Betacom fault codes

Last reviewed 25 August 2026.

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