Emergency Boiler Repairs: What to Do Right Now

I've written this so you can scan it quickly under pressure. Most boiler problems aren't dangerous, even when they're disruptive — but a few genuinely are, and knowing which is which is the most useful thing you can have to hand. If you can smell gas or you suspect carbon monoxide right now, skip straight to the gas and CO section and act on it before reading anything else.

What actually counts as a boiler emergency?

It's worth being honest about this, because treating every fault as a 999-level crisis just adds stress, and treating a genuine danger as "I'll sort it tomorrow" is how people get hurt. In rough order of urgency, a true emergency is:

• A smell of gas, or suspected carbon monoxide. This is the only category that's about your safety rather than your comfort. Act immediately — see below.
• A significant water leak from or around the boiler, especially if it's near electrics or coming through a ceiling.
• No heat or no hot water in cold weather, with a vulnerable person in the home — a young baby, someone elderly, someone unwell or anyone who can't keep warm easily. Cold homes are a real health risk, so this earns urgent treatment even though the boiler itself isn't dangerous.

A boiler that's simply stopped, with no leak, no smell and no one vulnerable affected, is urgent-ish rather than an emergency — annoying, but you have a bit of breathing room to work through the safe checks calmly.

If you smell gas or suspect carbon monoxide

This comes first because it's the one situation where speed matters more than diagnosis. Carbon monoxide is invisible and has no smell, so the warning signs are different from a gas leak — headaches, dizziness, nausea or breathlessness that ease when you leave the house, a lazy yellow or orange flame instead of crisp blue, sooty staining around the boiler, or a CO alarm sounding. Our guide on carbon monoxide and your boiler covers the signs in full. For either a gas smell or suspected CO, do this:

1. Don't touch any electrical switches. Don't turn lights, sockets or the boiler on or off — a spark can ignite gas. No matches, no naked flames, no smoking.
2. Open doors and windows to ventilate the property and let fresh air in.
3. Turn off the gas at the meter if you can reach the control handle easily and safely (turn it a quarter-turn so it sits across the pipe).
4. Leave the property and get everyone — and any pets — out into fresh air.
5. Call the free National Gas Emergency Service on 0800 111 999 from outside, not from inside the house. The line is open 24 hours a day, every day.
6. For suspected CO, also seek medical help. Tell your GP or A&E you think you've been exposed to carbon monoxide — a blood or breath test can confirm it.

Don't go back in, and don't try to find or fix the source, until the emergency engineer tells you it's safe. This part of the job is never DIY.

If there's a water leak

A leak is usually about protecting your home rather than your safety, but a steady drip near electrics or water coming through a ceiling needs quick action. You can do the safe, non-gas steps yourself:

• Turn off the boiler at the front controls or the fused spur, and switch off the central heating.
• Isolate the water if the leak is heavy — turn off the internal stop tap, or close the cold water valve under the boiler if you can identify it.
• Catch the water with towels and a bucket, and keep it away from sockets and the consumer unit. If water is near electrics, switch that circuit off at the consumer unit.

A small drip from a visible pipe joint might be something an engineer fixes quickly. But water from inside the casing, from the pressure-relief valve's external discharge pipe, or from the boiler itself points to an internal fault — that's a Gas Safe job, not a tighten-it-up-yourself one. If an overflow or outside pipe is dripping, our piece on a leaking overflow pipe explains what it usually means.

If there's no heat or hot water

This is the most common "emergency" call, and the good news is that several causes are genuinely homeowner-safe to check. Work through these calmly before you assume the worst — none of them involves opening the boiler:

• Power. Check the boiler's fused spur is switched on and that nothing has tripped at the consumer unit. After a power cut the programmer may have reset to the wrong time and simply isn't calling for heat.
• Controls. Set the thermostat above the current room temperature and check the timer or programmer is actually calling for heating or hot water. A flat thermostat battery is a surprisingly common culprit.
• Pressure. On a combi or system boiler, look at the gauge. Cold, it should read roughly 1 to 1.5 bar, rising towards 2 bar as it heats. If it's below about 1 bar you can usually top it up via the filling loop — the braided silver hose with a valve or two beneath the boiler. Open it slowly, watch the gauge reach about 1.5 bar, then close it firmly.
• Frozen condensate pipe. In freezing weather this is the number one cause of a sudden shutdown. You can thaw an accessible external pipe with warm — never boiling — water poured along the exposed section. See our guide to a frozen condensate pipe.
• A single reset. If the display shows a lockout, you can press the front-panel reset button once. If it locks out again, stop, note the fault code, and call an engineer rather than repeatedly resetting.

How to find a 24/7 Gas Safe engineer

Once the safe checks are done and the boiler still won't run — or the fault clearly points to the gas circuit, the fan, the ignition or a sensor — you need a professional. The single rule is that they must be on the current Gas Safe Register. (The old "CORGI" scheme stopped being the gas registration body back in 2009, so don't be reassured by that name.) To find someone fast:

• Search the Gas Safe Register directly for engineers in your postcode, and check the ID card of whoever turns up before they start.
• Call your boiler cover provider's emergency line if you have a policy — for many households this is the quickest route, because they dispatch an approved engineer for you.
• Be wary of out-of-hours premiums. Independent emergency callouts at night, at weekends or on bank holidays cost the most — indicatively £100 or more just to attend, before any parts or labour — which is exactly when demand peaks and engineers are hardest to book.

Where boiler cover helps in an emergency

This is the practical case for cover, separate from the everyday-service argument. A breakdown rarely happens at a convenient hour, and the value of a policy in a genuine emergency comes down to three features worth checking before you buy:

Feature	Why it matters in an emergency
24/7 call-out	You can get help at 2am on a freezing Sunday, not just in office hours.
No call-out fee	You're not paying a premium just for an engineer to attend.
Approved engineer network	The provider finds and dispatches a Gas Safe engineer, so you don't have to ring round.
Stated response times	Some plans prioritise "no heat or hot water" or vulnerable-customer callouts.

Features and response times vary between providers — always check the policy terms before buying.

Whether that's worth the monthly cost depends on your boiler's age, your budget and how you'd feel about a surprise bill on the coldest night of the year. Our guide on whether boiler cover is worth it walks through the trade-offs honestly, and you can compare boiler cover from a selected panel of UK providers to see which plans include 24/7 emergency support. This is information to help you decide, not personal advice, and we show a selected panel rather than the whole market.

Frequently asked questions