When to call a Gas Safe registered engineer

The signs that mean stop and call: a smell of gas, soot, yellow or orange flames, fumes, a boiler that will not light. What to do in a gas emergency, and how to check an engineer is registered.

This guide is deliberately short on method. Gas work is not a DIY job. It tells you when to stop, what a householder can safely do in an emergency, and how to find someone qualified. There are no product links on this page.

If you smell gas

The Health and Safety Executive's domestic gas FAQs say that if you suspect a gas leak you should immediately:

call the National Gas Emergency freephone number: 0800 111 999;
open all the doors and windows;
shut off the gas supply at the meter control valve, if you know where it is and can reach it safely.

HSE also says it is illegal for anyone to use a gas appliance if they suspect it is unsafe. Turn the appliance off and do not use it again until a Gas Safe registered engineer has checked it.

If you feel unsafe, leave the property and make the call from outside. Do not go back in to look for the leak.

The 0800 111 999 number is the one HSE gives on that page. If you live in Northern Ireland, check the official gas emergency details for Northern Ireland, which are separate from the Great Britain service.

Signs you must stop and call

Stop using the appliance and call a Gas Safe registered engineer if you notice:

a smell of gas (use the emergency steps above first);
yellow or orange flames instead of blue on a gas hob, fire or boiler, except on appliances designed to show that colour, such as fuel-effect fires;
soot or yellow or brown staining on or around an appliance;
a pilot light that keeps going out;
more condensation than usual on the inside of windows in the room with the appliance;
fumes, or a flue that is damaged, blocked or loose;
a boiler that will not light or keeps locking out, after you have checked the simple user controls in its instructions, such as the thermostat, timer and power;
a carbon monoxide alarm sounding.

HSE lists yellow or orange flames, soot or staining, pilot lights that frequently blow out, and increased condensation inside windows as signs of incomplete combustion that may produce carbon monoxide.

Carbon monoxide

Carbon monoxide (CO) has no colour, smell or taste. HSE lists early symptoms including headaches or dizziness, breathlessness, nausea, tiredness, chest or stomach pains, erratic behaviour, visual problems and loss of consciousness, and says they can be mistaken for food poisoning, viral infections, flu or tiredness.

If you think an appliance is producing CO, HSE's advice is to call the National Gas Emergency Service on 0800 111 999, switch the appliance off and shut off the gas at the meter control valve, open doors and windows, and seek urgent medical advice from your GP or an A&E department if you have symptoms. HSE strongly recommends CO alarms as one useful precaution. An alarm is not a substitute for having appliances checked.

Work that is always for a Gas Safe registered engineer

Any work on:

gas pipework, including moving, extending or capping it;
boilers, including the inside of the casing;
flues and chimneys for gas appliances;
gas fires, cookers, hobs and water heaters;
the gas meter connections.

HSE says anyone employed to work on gas appliances in domestic premises must be a Gas Safe registered engineer and competent in that area of gas work. The Gas Safety (Installation and Use) Regulations 1998 are the main rules. Leatmere does not publish DIY instructions for any of this work.

Water-side jobs near a boiler, such as bleeding radiators, are covered in our radiator guide. Anything beyond the user controls described in your boiler's instructions is for an engineer.

How to find and check an engineer

Use the Find an engineer or Check an Engineer service on the Gas Safe Register website.
Ask to see the engineer's Gas Safe Register ID card. HSE notes that the engineer's competencies are marked on the back of the card, so you can check they cover the job you need.
HSE gives the Gas Safe Register freephone helpline as 0800 408 5500, and says you can check a registered business by texting GAS and the business registration number to 85080.
HSE strongly advises that gas appliances, flues and pipework are serviced at least annually by a Gas Safe registered engineer.

Can I turn off the gas myself in an emergency?

Yes, if you know where the meter control valve is and can reach it safely. HSE's advice is to shut off the gas supply there, open doors and windows and call 0800 111 999.

My boiler will not light. Can I fix it?

You can check the user controls described in the boiler's instructions, such as the power, timer and thermostat. Beyond that, call a Gas Safe registered engineer.

How do I know an engineer is registered?

Check their ID card and look them up on the Gas Safe Register website.