Gas emergency guidance
Gas hob leaking or a burner that won't light — what to do
A hob that hisses when off, a burner that won't light, or a smell of gas from the cooker are all signs of a fault with the burner cap, thermocouple, valve or connection hose. It's usually a quick Gas Safe fix — but the diagnosis and repair are not DIY.
Do this right now
If you can smell gas after turning the hob off, treat it as a live gas leak: leave the property and call 0800 111 999 before doing anything else.
- 1
Turn every hob knob to OFF and check they clicked off fully
Sometimes a knob is slightly rotated and gas is trickling out. Positively confirm each one is at the off position.
- 2
If you can smell gas, leave the property
Open windows and doors on your way out, take everyone outside, and call the National Gas Emergency Service on 0800 111 999 from outside.
- 3
If no smell — isolate the appliance
Turn the isolation valve behind the cooker (a lever on the flexible bayonet or hard-piped connection) to the off position. If you can't reach it or aren't sure where it is, turn the gas off at the meter emergency control valve.
- 4
Open a window and ventilate the kitchen
Even a small residual gas smell needs airing before an engineer arrives.
- 5
Do not use the hob again until it has been inspected and repaired
Cover the hob or tape a note on it so nobody accidentally turns a knob.
- 6
Book a Gas Safe registered engineer for the follow-up repair
The fault is usually a burner cap, ignition electrode, thermocouple, tap seal, or the flexible connection hose — all Gas Safe work.
Do NOT do these
- Do not try to relight the burner repeatedly if it fails once.
- Do not use a lighter or match to see if a burner is 'working'.
- Do not tighten or slacken pipe fittings yourself — that includes the flexible hose.
- Do not use aerosols (WD-40, cleaner) on or near a leaking hob.
- Do not run the extractor fan at high speed if a strong gas smell is present (motor spark risk).
- Do not ignore a hissing sound coming from the hob when it's off.
Once the property is made safe
After the National Gas Emergency Service has attended and issued their paperwork, a Gas Safe registered engineer needs to make the follow-up repair before the gas can be turned back on. Only book us after the immediate emergency has been handled.
- A Gas Safe engineer will inspect the burner heads, caps, ignition electrodes, thermocouples and the flexible bayonet connector.
- Typical repairs: replace a bayonet hose (£70 – £120 fitted), swap a thermocouple or ignition module (£90 – £160), or replace a whole burner assembly (£140 – £260).
- If the hob is more than 12 years old and multiple parts have failed, an honest 'repair vs replace' conversation is worth having.
- Ask us to combustion-test any other gas appliances in the property while we're on site.
KJ Plumbers promise: £50 fixed diagnostic, transparent written quote before any work, and if we can't fix the fault we diagnosed the £50 is refunded. All gas work carried out only by Gas Safe registered engineers — ask for the card on arrival.