BoilerFaultCodesYour boiler's internal safety connection is working correctly, which typically means the system is performing a normal startup check or confirming the pilot light is healthy.
This is a minor fault. Keep an eye on it and mention it at your next annual boiler service. Reset the boiler and see if it clears.
Technical description: THERMOCOUPLE CIRCUIT IS SATISFACTORY
What causes this fault?
This code appears when the boiler's internal safety sensor successfully detects that the pilot light or main burner is lit. It is a confirmation that the magnetic valve is being held open by the heat from the flame, allowing gas to flow safely. Unlike an error code, this indicates the safety circuit is functioning exactly as it should during the ignition process.
DIY fix possible
Check that the gas supply to the property is turned onMonitor the display to see if the code clears during the ignition sequenceEnsure the pilot light window is clear of obstructions
Find a Gas Safe engineer
Search the official register for a qualified engineer in your area.
Gas Safe Register →Protect yourself from future repair bills
A boiler cover plan would cover faults like B — no call-out fees, no surprises.
Affiliate links — we may earn a commission at no extra cost to you.
Glow-worm 56 2 is discontinued — time for a new one?
Parts for discontinued models can be hard to find and expensive. A new A-rated boiler could save you money on both repairs and energy bills.
Affiliate links — we may earn a commission at no extra cost to you.