What to Do When Your Boiler Breaks Down

Quick checks before calling for help

• Check the boiler pressure gauge — low pressure is a very common cause of boilers cutting out
• Check your thermostat has working batteries and is set above room temperature
• Check the fuse for the boiler hasn't tripped at the consumer unit
• Check for an error code on the boiler display and note it down
• Check the condensate pipe isn't visibly frozen if it's a cold snap — a common winter fault
• Try a single reset of the boiler following the manufacturer's instructions, usually by holding the reset button for a few seconds

What an error code tells you

Most modern boilers display a fault code when something goes wrong. Manufacturers publish what these codes mean, and a quick search of your boiler's make, model and the code can narrow down whether it's something minor or a component failure. Even if you can't fix it yourself, having the code ready speeds up diagnosis when an engineer arrives.

Frozen condensate: a common winter cause

During a cold snap, the condensate pipe that carries waste water away from the boiler can freeze, particularly where it runs outside the property. This triggers a safety lockout even though nothing else is actually wrong with the boiler. If you can safely reach the external pipe, gently warming it with a warm (not boiling) water-soaked cloth can sometimes clear a partial blockage, but never attempt to access the boiler casing itself to investigate further.

Staying warm and safe in the meantime

• Use electric heaters carefully and don't leave them unattended
• Run taps briefly to check whether you still have hot water from an immersion heater if fitted
• Keep an eye on elderly or vulnerable household members if the property is getting cold
• Never attempt to open or repair the boiler casing yourself — this is gas appliance work and must be left to a Gas Safe registered engineer

What to have ready when you call an engineer

• The boiler's make and model, usually on a sticker inside the front cover or in the manual
• Any error code shown on the display
• How long the boiler has been faulty and whether it's happened before
• Roughly how old the boiler is
• Whether you've already tried a reset, and what happened when you did

Repair or replace?

For an older boiler with a history of faults, a breakdown is often the point at which it's worth weighing up repair against replacement. An engineer can advise honestly on which makes more sense based on the boiler's age, the cost of the repair, and its likely remaining lifespan. If replacement turns out to be the sensible route, new boiler quotations are handled separately from a repair callout.

Notifiable gas work and why it matters

Some boiler repairs go beyond a routine fix and count as notifiable gas work, meaning the completed job must be registered with the relevant authority by the Gas Safe registered engineer who carries it out. This typically applies to certain flue replacements or new gas appliance installations rather than most straightforward breakdown repairs, but it's a good reminder of why unqualified work on a boiler isn't just risky, it can also leave your home without the paperwork needed for insurance or a future sale.

What a breakdown callout typically costs

Boiler breakdown diagnosis and repair during the day is charged at our standard £99 per hour, rising to £120 between 5pm and 7pm, £185 out of hours, and £220 on Sundays and bank holidays, all with a one-hour minimum then billed in 30-minute increments. There's no separate call-out fee on top of these rates. Any replacement parts needed, such as a diverter valve or pump, are identified during diagnosis and quoted before they're fitted, so there are no surprises on the invoice.

Preventing the next breakdown

• Book an annual service to catch developing faults before they cause a full breakdown
• Keep the condensate pipe insulated if it runs through an unheated space or outside the property
• Don't ignore intermittent fault codes that clear themselves — note them down and mention them at the next service
• Bleed radiators and check pressure regularly so a genuine fault isn't confused with a simple air lock