Glow-worm F.27: safety switch-off: fault in flame detection

Engineer only

The boiler has a problem detecting the flame correctly. Glow-worm lists moisture on the electronics, a faulty flame monitor or a leaking gas valve.

What you can safely do

There is nothing you can safely do yourself with this one. Leave the boiler off and book an engineer.

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.27 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.

Model	Meaning	Causes listed for engineers
Energy range	Safety switch-off: fault in flame detection	Moisture on the electronics, flame monitor electronics defective, gas solenoid valve leaking
Betacom A range	Flame detection fault	Not listed