Glow-worm F.61 fault codewhat it means and how to fix it
The board cannot drive the gas valve properly — a short in its wiring, coils shorted to earth, or the electronics. The valve stays shut until an engineer has traced it.
Take care
Get a Gas Safe registered engineer to look at your Glow-worm F.61
We do not pass enquiries to a repair firm, so there is no form here. Find a Gas Safe registered engineer through the Gas Safe Register, and ask to see their registration card when they arrive — it is the register, not the van, that tells you they are qualified.
What F.61 means
Glow-worm define F.61 as "Fault: Gas valve assembly control" with three causes: "short circuit/short-to-ground in wiring harness to gas valve assembly, gas valve assembly defective (coils shorted to earth), electronics defective". The Compact manual calls the same thing "Fault: Fuel control valve" and lists the fix order an engineer follows — check and if necessary replace the harness to the valve, then the valve, then the PCB.
What the code means for you is simpler: the safety circuit that opens and modulates the gas valve has failed its own check, so the board refuses to energise the valve at all. No gas is being released — this is the opposite of F.62 — and the boiler is cold and safe, but nothing you can do from the front will move it. The two-digit Ultracom2, Betacom 24a and Betacom2 boilers group F61 with F62 to F67 as "fault in the main board — gas valve command fault", and their installation manual adds a check that explains one common F61 on those boilers: that the appliance DSN number is correct, because a board fitted without the right product code drives the valve wrongly.
On the Ultracom hxi and Flexicom ranges the equivalent is F14, "gas valve control defective". Glow-worm's user guides for every generation reserve this code for a competent person, and there is no reason to press reset more than once: a wiring short does not clear itself.
What causes it
| Cause | What is actually happening | How likely |
|---|---|---|
| Harness to the gas valve shorted or chafed | Glow-worm's first cause and the cheapest. The loom to the valve runs close to the burner door and the casing, and a conductor rubbed through to earth is what the board detects when it tests the circuit. | Common |
| Gas valve coils shorted to earth | The solenoid or modulating coil inside the valve has broken down. Glow-worm print it as "coils shorted to earth" and the valve is replaced as an assembly; the engineer will meter the coils before condemning it. | Occasional |
| Driver stage on the PCB failed | Third on Glow-worm's list. Sometimes the consequence of a shorted coil taking the output with it, which is why a board changed alone can fail again if the valve was not tested. | Occasional |
| Wrong product code after a board change — two-digit boilers | The Ultracom2 and Betacom2 manuals tell the engineer to check the DSN against the nameplate for F61. A replacement board left with the wrong device number is a known way to earn this code with nothing physically wrong. | Rare |
Can you fix it yourself?
Stop — this needs an engineer
What it costs to fix
Typical repair cost
£90–£450
Time on site
1h 30m
Harness repair £90–£150. Gas valve £250–£400. PCB £250–£450.
Typical UK prices including parts and labour, updated September 2026. Your quote may differ.
Parts you may need
We may earn a commission if you buy a part through one of these links. It does not change what you pay, and it does not affect which parts we list.
Glow-worm gas valve assembly
£90–£200Authorised Glow-worm parts distributor
Price checked 28 September 2026
Glow-worm main PCB
£150–£320Authorised Glow-worm parts distributor
Price checked 28 September 2026
Own this appliance and had this code? . Nothing is published until a person has read it.
Related Glow-worm fault codes
- F.28Get it checkedThree ignition attempts have failed and the boiler has locked out. Glow-worm's guides let you check the gas supply and the condensate pipe and reset three times before calling anyone.Related: ignition and gas supply
- F1Get it checkedOn Ultracom, Flexicom and Ultrapower boilers F1 is an ignition lockout after five failed attempts, and Glow-worm's guides let you reset it. On Energy and Ultimate boilers F.01 is the return sensor instead.Related: ignition and gas supply
- F.29Get it checkedThe burner lit and then the flame went out while running. Glow-worm blame the gas supply, flue gas recirculating, earthing, the spark transformer and, on newer manuals, a blocked condensate pipe.Related: ignition and gas supply
- F.27Stop — call an engineerThe boiler is sensing a flame when there should not be one. Glow-worm list moisture on the electronics, a failed flame monitor or a leaking gas valve. Not a reset job.Related: ignition and gas supply
- F.68Get it checkedThe flame is burning but its signal is unstable. Glow-worm list air in the gas, low gas pressure, a wrong combustion setting or injector, a poor electrode connection or a blocked condensate pipe.Related: ignition and gas supply
- F.62Stop — call an engineerThe gas valve did not shut off when told to — the flame signal lingered after the close command. Glow-worm list a delayed or leaking valve or the electronics. Switch off; call an engineer.Related: ignition and gas supply
Own a Glow-worm boiler? Save it and its codes come first next time.
Related guides
Common questions about Glow-worm F.61
Is gas escaping?
No. F.61 is the board declining to open the valve because it cannot trust the control circuit. F.62, the switch-off fault, is the one where the valve may not be closing.
Will a reset clear it?
Rarely, and if it does the fault is intermittent and will return. Glow-worm list no householder measure for F.61 on any range.
What does it cost?
A wiring repair £90–£150. A gas valve assembly £250–£400 fitted. A PCB £250–£450. The engineer should meter the valve coils before ordering either part.
Technical review
Not reviewed by an engineer
No engineer has read this page. Severity follows what the manufacturer publishes, and we would rather tell you that than let a byline imply a sign-off.
Sources and how we verified this
We establish the facts from the sources below and then write the explanation ourselves. We do not copy manufacturer wording and we do not host their manuals.
- Manufacturer technical and service documentation
- Manufacturer support portal
This page has not been reviewed by an engineer, and we would rather tell you that than imply otherwise. The severity rating follows what the manufacturer publishes: where they say isolate the appliance and call someone, so do we.