Smell gas? Leave the property and call the National Gas Emergency line on 0800 111 999
BoilerCodes
F.29Glow-worm

Glow-worm F.29: flame loss during operation

Checked against Glow-worm's own documentation: Glow-worm: Energy range fault codes and 3 more sources. Last reviewed October 2026. How we check

Check these first, then call an engineer

The boiler was running and lost its flame. Glow-worm's fault table lists a temporary break in the gas supply among the causes, and its homeowner advice says F.28 and F.29 often come down to the gas supply or a frozen condensate pipe.

What you can safely do

  1. Check your gas supply and prepayment meter credit.
  2. In freezing weather, check the condensate pipe outside and thaw it with warm (not boiling) water.

Call a Gas Safe engineer if

  • The code comes back after these checks.
  • You smell gas at any point. Leave the property and call 0800 111 999.
Find a Gas Safe engineer near you Opens the official Gas Safe Register search.

Applies to Energy range, Betacom A range. Codes can differ between models, so check your manual.

What F.29 means on each Glow-worm model

From Glow-worm's own fault tables. Your model name is usually on the front of the boiler or in the user manual.

ModelMeaningCauses listed for engineers
Energy rangeFlame lossGas supply temporarily stopped, flue gas recirculation, incorrect earthing, ignition spark failure
Betacom A rangeLoss of flame during operationNot listed

Common questions about Glow-worm F.29

What is the difference between F.28 and F.29?

F.28 means the boiler couldn't light when starting up. F.29 means it lost the flame while running.

Nearby Glow-worm codes

See all 41 Glow-worm codes

Sources

Last reviewed October 2026. Spotted something that doesn't match your manual? Email hello@boilercodes.co.uk and we'll check it. How we check