Glow-worm Energy Fault Codes
The Glow-worm Energy is the brand's core modern range — combi, system and regular versions built on parent company Vaillant's platform, which gives the Energy Vaillant-grade internals at a friendlier price. That parentage shows in the fault language: the Energy's F-codes track the Vaillant scheme closely, with F22 for low water pressure, F28/F29 for the ignition-failure and flame-loss pair, and F75 for the pump/water-pressure-sensor fault familiar from ecoTECs. For owners that shared platform is quietly excellent news: the diagnostic paths are the most travelled in the industry, parts are plentiful, and any engineer fluent in Vaillants reads an Energy at sight. The codes below are the ones Energy owners actually meet, each linking to its full cause-and-fix page.
Where Energy fault codes appear
The Energy has a digital display on the front: temperature and status in normal running, "F" plus a number when a fault trips. Record the exact number — the F-series packs many distinct diagnoses into neighbouring numbers (F28 versus F29 is failed-to-light versus lit-then-lost, and they lead different places).
Resetting a Glow-worm Energy
Press the reset button on the fascia briefly; the boiler clears the lockout and retries. F22 wants the system topped up to 1–1.5 bar via the filling loop first. The platform limits repeated resets on ignition faults by design — if a code returns after one reset, that is the diagnosis talking; look it up rather than pressing again.
Common Energy problems
Energy owners mostly meet the platform classics: F22 pressure loss, the F28/F29 ignition pair (with the frozen condensate pipe its great winter cause), and F75 as pumps and pressure sensors age. Sensor codes in the F.60s and F.70s appear as installs get older. Clean system water — filter and inhibitor — is the difference between a quiet Energy and a talkative one.
Most common Energy fault codes
- F22 The F22 fault code on a Glow-Worm boiler signals that the water pressure inside your… Read more →
- F28 The F28 code means your Glow-Worm boiler attempted to light the burner, failed to detect… Read more →
- F29 The F29 code on a Glow-Worm boiler means the burner managed to light but the flame then… Read more →
- F75 The F75 code appears when the boiler's pressure sensor fails to detect any change in… Read more →
- F27 The F27 code indicates that your Glow-Worm boiler has attempted to ignite but its flame… Read more →
- F23 The F23 code means your Glow-Worm boiler has detected an excessive temperature difference… Read more →