Boiler not working after a new kitchen was fitted? Here's what to check

Last checked: November 2026 · Boilers in a kitchen or kitchen cupboard · 5 minute read

Safety first. Read this before anything else.

  • If you smell gas: don't use switches, open the windows, turn off the gas at the meter if you can, leave the property and call 0800 111 999.
  • If your carbon monoxide alarm goes off, or anyone feels dizzy, sick or has a headache that eases when they go outside: switch the boiler off, open windows, get everyone outside and call 0800 111 999.
  • If the flue (the pipe from the top or back of the boiler that takes the fumes outside) was moved, cut, knocked or boxed in during the work, don't use the boiler until a Gas Safe registered engineer has checked it.

Never take the boiler's cover off.

Your new kitchen looks great, but the boiler has stopped working, shows a fault code, or keeps cutting out. Kitchen fitters often have to turn things off, move pipes, and build cupboards around the boiler. So it's quite common for something to be left off or disturbed. Many causes are simple. Some need a Gas Safe registered engineer.

Why it happens

To fit a kitchen around a boiler, fitters often:

Step by step

1Check the flue wasn't disturbed

Ask the fitters, or think back: was the boiler taken off the wall or moved? Was the flue pipe cut, moved or knocked, or have new units or panels been built around it?

If the answer to any of these is yes, don't use the boiler until a Gas Safe registered engineer has checked it. A flue that isn't sealed properly can leak carbon monoxide into your home, which you can't see or smell. You should also have a working carbon monoxide alarm in the room with the boiler.

Also, boiler manufacturers say how much space must be left around the boiler. Most also require that flue joints stay accessible for inspection, so they can't be fully boxed in without inspection hatches. If your boiler is now in a very tight cupboard, ask an engineer to check.

2Check the boiler has power

  • Is the boiler's display or light on at all? If not, look for its switch nearby, usually a fused switch on the wall, sometimes now hidden inside a cupboard or behind a unit. Make sure it's on.
  • Check your fuse box for anything that's tripped. Push it back on once. If it trips again, call an electrician.
  • Check the heating thermostat and timer are on and calling for heat. These sometimes need resetting after the power has been off.

3Check the gas is on

  • Is your gas hob working? If not, the gas may be off at the meter. The lever on the pipe by the meter should line up along the pipe when on.
  • There may also be a gas valve under the boiler, usually with a yellow handle, which fitters sometimes turn off. It's on when the handle lines up with the pipe.

If you're not confident, or the gas was turned off for the work and you don't know why, ask a Gas Safe registered engineer to turn it back on and check everything is safe.

4Check the water pressure

If your boiler has a pressure gauge, check it reads about 1 to 1.5 bar when cold. If pipes were moved or the water was turned off, it may have dropped. Our guide Boiler stopped working after bleeding the radiators shows how to top it up safely using the filling loop.

5Check the condensate pipe

Modern condensing boilers produce water (condensate) that drains away through a plastic pipe, usually white or grey, about the width of a thumb. In a kitchen it often connects into the sink waste under the sink, or runs outside.

If it's been disconnected, squashed, kinked or pushed up so water can't drain downhill, water backs up into the boiler and it shuts down with a fault. Look along the pipe as far as you can see it:

  • Is it still connected at both ends?
  • Does it run downhill all the way, with no dips or sharp bends?
  • Has a cupboard, drawer or plinth been pushed against it?

If it's clearly disconnected or squashed, ask the kitchen fitter to come back, or call a heating engineer. Don't cut or reroute it yourself.

6Reset once, then call for help

If you've found and fixed something simple, like the power or a low pressure, press the boiler's reset button once. If it fires up and keeps working, you're done.

If it locks out again, don't keep resetting it. Note any fault code, and call a Gas Safe registered engineer. You can check they're registered at gassaferegister.co.uk.

If the kitchen work caused the problem, tell the kitchen company. Many will pay for the engineer's visit, or send their own. Take photos of the boiler, the pipes underneath and any changes made, and keep a note of dates and fault codes.

Questions people ask

Can kitchen fitters move my boiler?

Only a Gas Safe registered engineer is allowed to disconnect, move or reconnect a gas boiler, its gas pipe or its flue. Many kitchen companies use one for this part of the job. If you're not sure who did it, ask for their Gas Safe registration number and the paperwork for the work.

Can the boiler be boxed in a kitchen cupboard?

Usually yes, as long as the manufacturer's minimum gaps around it are kept and the flue can still be inspected. Your boiler's manual lists the gaps needed. Your engineer can check this at the next service.

Will this affect my boiler warranty?

It can, if the boiler, flue or condensate pipe were changed by someone who wasn't qualified to do it. Ask the engineer who checks it to note anything that isn't right, and raise it with the kitchen company.

Related guides

This guide is general information, not professional advice. It was checked against Gas Safe Register, boiler manufacturer and heating industry guidance in November 2026. If in doubt, contact a Gas Safe registered engineer.