Quick Answer
Check the fused spur and consumer unit first, then your thermostat batteries, then the pressure gauge (it should read 1.0 to 1.5 bar). Test your gas hob to confirm the supply is on, and check the external condensate pipe for ice. Most breakdowns trace back to one of these five things.
Never use a gas hob or oven to heat a room. Press the reset button once, wait two minutes, then try once more at most. Open the cabinet doors under your sink to protect the pipework inside if the heating stays off for long.
If the checklist doesn’t get you anywhere, our fixed diagnostic rate is £120 on a weekday, rising to £160 on a Saturday, £180 in the evening and £220 for a Sunday or bank holiday. Our line is answered 24/7 across West and North West London.
Boilers work far harder in winter than they ever do in summer. That’s when the weak point in the system usually shows itself, and it’s what fills our diary across Kilburn, Ealing and Fulham every cold snap. Here’s exactly what to check before you call, and what to do while you wait.
Key Takeaways
- Five checks come before any call: power, thermostat batteries, pressure gauge, gas supply, and the external condensate pipe for ice.
- Winter breakdowns are rarely one single cause: our engineers see pressure loss, PCB faults and frozen pipes in roughly equal measure once it turns cold.
- Overloaded extension leads are the mistake we see most: daisy-chaining fan heaters is a genuine fire risk, not just an inconvenience.
- Fixed pricing if you need us: £120 weekday diagnostic, rising for evenings and weekends, with a written quote before any repair starts.
The 10-minute pre-call checklist
Work through these in order. Each one takes under two minutes, and together they cover the large majority of winter breakdowns before you ever need to pick up the phone.
Check the fused spur switch near the boiler is on, and check the consumer unit for a tripped RCD breaker. This is safe to check yourself. It’s a simple flick, not an electrical repair.
Set it two or three degrees above room temperature and check the display is lit. If it’s a wireless stat, swap the batteries. A flat battery is one of the most common “boiler’s broken” calls that isn’t the boiler at all.
The gauge on the front of the boiler should read between 1.0 and 1.5 bar. Below 0.8 bar, most boilers lock out. You can safely top it up yourself using the filling loop, following your boiler’s own instructions.
Light a ring on the kitchen hob. If it doesn’t light, check a prepayment meter has credit, or that no gas appliance has tripped the supply. If the hob’s fine but the boiler still won’t fire, the fault is inside the boiler.
Look outside for the plastic pipe running down the wall near your boiler. A gurgling noise before lockout usually means it’s frozen. Pour warm tap water along the pipe. Never boiling water. It often clears the ice in minutes.
If a check fails, that’s usually your answer. Everything passes and it still won’t fire? Stop guessing. Book an engineer instead.
Mistakes we see homeowners make while they wait
Losing heating in the cold is stressful. It’s easy to reach for the nearest fix. The one our engineers see most often, and the one that worries us most, is overloading fan heaters on extension leads.
Extension Lead Overload
Fire RiskRunning one or more 2kW fan heaters through a coiled or daisy-chained extension lead, often overnight.
Plug heaters directly into a wall socket, one per socket, and never leave them running unattended overnight.
Gas Hob for Heating
Carbon Monoxide RiskLeaving the oven or hob burning with the door open to warm the kitchen.
Use an electric oil-filled radiator from a wall socket. Never a domestic gas appliance without a flue.
Repeated Resets
Ignition DamagePressing reset again and again, hoping it eventually catches.
Press it once, wait two minutes, try once more at most. Then stop and call us.
Never use a gas cooker, hob or camping stove to heat a room. Without a flue, they release combustion gases directly into the air you’re breathing. That’s a genuine carbon monoxide poisoning risk. If you smell gas at any point, call the National Gas Emergency Service free on 0800 111 999 and leave the property if you’re told to.
Keeping the house warm while you wait
Close the doors to any rooms you’re not using and draw heavy curtains after dark. That traps what heat is left in the rooms you’re in, rather than losing it across the whole house.
An electric oil-filled radiator, plugged straight into its own wall socket, is the safe way to add heat in the meantime. Check the socket’s rating against the heater’s wattage. Don’t guess. Don’t run several from the same circuit.
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Gas Safe registered engineers (657972) covering West and North West London. Fixed diagnostic rates from £120 weekday daytime, £160 Saturday, £180 evening and £220 Sunday or bank holiday, with a written quote for any repair before we start.
Stop your pipes freezing too
A boiler that’s off for more than a few hours in sub-zero weather isn’t just a comfort problem. Standing water in exposed pipework can freeze. It expands. It splits joints. That’s a far more expensive fix than the boiler itself.
- Open cabinet doors under your kitchen sink and bathroom basin. It lets warm room air reach the copper pipework hidden inside, which is usually the coldest, most exposed run in the house.
- Let a cold tap trickle very slightly if temperatures are staying below freezing for more than a day. Moving water rarely freezes solid.
- Find your stopcock now, not after a pipe has already split. It’s usually under the kitchen sink or near where the mains enters the property. Knowing where it is saves minutes if a pipe lets go.
What our engineers check first on arrival
Our engineers follow the same sequence on every winter breakdown call. Power first. Then pressure. Then the fault code, then the flue and condensate run. Checking the fault code before touching anything else tells us what the boiler’s control board has already recorded, which is often faster than working back from symptoms alone. Only once that’s confirmed do we open the casing to look at the flue and condensate pipework.
What this usually turns out to be
There isn’t one single cause behind most winter callouts. Our engineers see a genuine mix. Pressure lost to expansion as the system heats and cools more than it does in summer, something a pre-winter service usually catches before it becomes a breakdown. PCB faults on boilers working harder and longer than usual. And in a proper cold snap, like the Beast from the East a few years back, frozen condensate pipes across the board. Which one you’ve got depends on your own checklist results above.
A frozen pipe? Our full guide to thawing a condensate pipe safely walks through it step by step. Gauge reading low instead? See why boilers lose pressure for the full diagnosis.
Renting? Tell your landlord straight away
If you’re a tenant, report a boiler breakdown to your landlord or managing agent as soon as you’ve done the checks above. Landlords have a legal duty to keep the heating system in good repair. A written or messaged report with the date and what you’ve already checked gets the clock started. Our landlord gas safety checks also confirm a property’s appliances are safe before winter sets in.
Stop and call a Gas Safe engineer if…
- The reset has failed twice. Don’t press it a third time. Repeated resets can flood the burner with unburnt gas and damage the ignition board.
- You smell gas. Turn off the meter control valve, open windows, and call 0800 111 999 immediately.
- The pressure keeps dropping again within a day of topping it up. That’s not a one-off. It points to a leak somewhere in the system.
- You’ve checked all five items and nothing’s changed. It’s a fault inside the boiler. The casing stays on.
What our engineer does once they’re with you
- Runs the same power, pressure, fault code and condensate sequence as the pre-call checklist, but with test equipment on hand to confirm each reading.
- Opens the casing to check the ignition electrode, gas valve and PCB, since these are the parts that take the most strain during a hard winter.
- Tests the flame picture through a full burn cycle rather than just watching it light, to catch a fault that would otherwise show up again within days.
- Repressurises the system properly if the drop was caused by a leak, not just a top-up, and traces where the water’s actually going.
- Agrees a fixed price for any parts or further work before starting, and explains what they found in plain terms.
Not every winter fault is a breakdown
A few things get mistaken for a full breakdown. They’re something smaller.
- Radiators cold but the boiler’s firing fine usually means trapped air, not a boiler fault. Bleeding the radiator often sorts it in minutes.
- Hot water working but no heating points to a diverter valve or a zone valve stuck in the wrong position, not a dead boiler.
- A boiler that cuts out only on the coldest nights and runs fine otherwise often comes back to the condensate pipe specifically, even without an obvious gurgle first.
Symptoms don’t match the checklist cleanly? Rule these out first. Don’t assume the worst.
Protect against the next breakdown
A pre-winter service is what catches pressure loss from expansion before it becomes a breakdown. That’s exactly the kind of drift an annual check is built to spot. Our Homeowner Plan at £9.99 a month includes annual servicing plus priority dispatch. You’re not left choosing between checking the boiler and paying for petrol that month. If your boiler’s over 12 to 15 years old and this isn’t its first winter fault, it may also be worth reading about boiler installation rather than patching an ageing system through another cold season.
Frequently asked questions
What should I check first if my boiler breaks down in winter?
Work through five checks in order. The fused spur and consumer unit, your thermostat batteries, the pressure gauge (1.0 to 1.5 bar), the gas supply using your kitchen hob, and the external condensate pipe for ice. Most winter breakdowns trace back to one of these five things.
Is it safe to use my gas oven or hob to keep the house warm?
No. Never use a gas cooker, hob or camping stove to heat a room. Domestic gas appliances without a flue release combustion gases straight into the air. That’s a genuine carbon monoxide risk. Use an electric oil-filled radiator plugged directly into a wall socket instead.
How many times can I press the boiler reset button?
Press it once, wait two minutes, and try once more if it hasn’t fired. That’s the limit. Pressing it repeatedly floods the combustion chamber with unburnt gas and can damage the ignition board. A simple fault turns into a costly repair.
Can I fix a winter boiler breakdown myself, or do I need an engineer?
The five pre-call checks are safe DIY, along with topping up pressure via the filling loop and thawing an easily reached external condensate pipe with warm water. Anything behind the boiler’s casing, including gas and electrical components, is Gas Safe engineer work only.
How much does an emergency callout cost in West London?
Our fixed diagnostic rate is £120 on a weekday, £160 on a Saturday, £180 for an evening visit, and £220 for emergency dispatch on a Sunday or Bank Holiday. Any repair beyond that gets a written quote first.
How do I stop my pipes freezing while the boiler is off?
Open the cabinet doors under sinks and basins so warm room air reaches the pipework inside, and let a cold tap trickle slightly if it’s staying below freezing for more than a day. Locate your stopcock now, in case a pipe does split later.
I rent my home, what should I do if the boiler breaks down?
Report it to your landlord or managing agent straight away, in writing, once you’ve worked through the checklist above. Landlords have a legal duty to keep the heating system in good repair, and a written report with the date gets that process moving.
Need an engineer out for a winter breakdown?
Tell us your fault code if you have one, what you’ve already checked, and whether the boiler resets at all. We’ll get an engineer to you with a clear fixed price agreed before any work starts.
- WhatsApp us: Book in 60 seconds
- Call 020 8051 2124: our line is answered 24/7 and we’ll get your details to an engineer.
- Book online: emergency boiler repair · Homeowner Plan
We’re Gas Safe registered (657972) and cover West and North West London. Heating that just works, no drama.
