BoilerBuddy · emergency safety
Three things to do right now, in the right order.
This page is built for the minutes after you realise something is wrong — a gas smell, a carbon-monoxide alarm going off, or a boiler that keeps locking out and will not stay lit. Read the section that matches what is happening in your home, follow the three steps in order, and use the tap-to-call numbers below.
These steps are not a substitute for a qualified opinion — they are the safe action until a Gas Safe registered engineer or the emergency services takes over.
Scenario 1 — gas smell
You can smell gas in or near the house.
A gas smell is a stop-and-act situation, not a fix-it-yourself one. It could be the boiler, the supply pipe, or a nearby appliance — only a Gas Safe registered engineer is qualified to find out, and the first safe action is to leave the property and call the gas emergency line.
STOP
Do not turn any switches on or off, do not light a match, do not use a mobile phone inside, and do not smoke. Any of those can ignite leaked gas.
LEAVE
Open doors and windows on the way out if you can do so without stopping to fiddle with anything. Take everyone — including pets — out of the property.
CALL
From outside the property, call the National Gas Emergency Service. The line is open 24/7 and calls are free.
If you can, take a clear photo of the fault code or display before you do anything that resets it. The exact code text and any flashing LED pattern is the single most useful thing to give an engineer.
Scenario 2 — CO alarm sounding
Your carbon-monoxide alarm is going off.
A CO alarm going off is a medical-emergency signal, not a hint to open a window and carry on. Carbon monoxide is invisible and odourless — the alarm is the only warning you have, and it should be treated as real until cleared by a registered engineer and the alarm itself is independently confirmed.
STOP
Switch the boiler off at the controls. Do not reset it and do not run it again until a Gas Safe registered engineer has cleared it. Do not silence the CO alarm to keep using the heating.
LEAVE
Get everyone out, including pets. Open doors and windows on the way out if it costs you no delay. Do not go back in for anything you can come back for later.
CALL
From outside, call the National Gas Emergency Service on 0800 111 999. Call 999 as well if anyone is seriously unwell or needs fire and rescue. Tell them the CO alarm has sounded.
If you can, take a clear photo of the fault code or display before you do anything that resets it. The exact code text and any flashing LED pattern is the single most useful thing to give an engineer.
Scenario 3 — repeated lockouts
Your boiler keeps locking out and resetting does not stick.
One lockout from cold start is usually a self-protective reset you can ride out. Repeated lockouts — especially after the boiler relit and ran briefly — usually mean the boiler has shut itself down for a real reason (ignition, flame loss, overheating). Keep resetting and you can mask the fault the engineer needs to see.
STOP
Stop pressing the reset button. Do not keep turning the boiler off and on in the hope it will stick. Repeated resets on a real fault can mask the symptom and erase the diagnostic the engineer needs.
LEAVE
Switch the boiler off at the controls and leave it off. Note the exact fault code on the display and any flashing LEDs (which ones, and in what pattern) for the engineer who visits.
CALL
Book a Gas Safe registered engineer — not a general handyman and not a friend who “knows about boilers”. Only a registered engineer is legally allowed to work on gas appliances.
If you can, take a clear photo of the fault code or display before you do anything that resets it. The exact code text and any flashing LED pattern is the single most useful thing to give an engineer.
You’re safe — back to triage
If you’re not in immediate danger, return to the triage flow.
The triage flow is built for non-emergency symptoms — cold radiators, no hot water, pressure drops, error codes. Tell BoilerBuddy what your boiler is doing and it will walk you through the safe-at-home checks first, then route you to a registered engineer if that’s the right answer.
Resuming the diagnostic
Resets anything you filled in. Safe at any point — the symptoms and answers are yours to type again.
BoilerBuddy is the conversation before the engineer visit — never a substitute for one. UK Gas Safety (Installation and Use) Regulations reserve appliance work for Gas Safe registered engineers, and this page is no different.