Boiler Breakdown London
No heat, no hot water, or a fault code you can't clear? Our Gas Safe engineers respond same day across London — diagnosis from £95, fixed price before any repair starts.
Do NOT switch any lights or appliances on or off. Open windows. Turn off gas at the meter. Leave the property. Call 0800 111 999 (National Gas Emergency — free, 24/7). Only call us after the property is declared safe by the network operator.
Try These First — 30% of Breakdowns Resolve Without a Call-Out
Check the pressure gauge
Most boiler breakdowns are low pressure. Gauge should read 1.0–1.5 bar cold. If below 0.8 bar, repressurise (see filling loop under the boiler). If it's regularly dropping, call us — there's likely a leak.
Check for a frozen condensate pipe
In cold weather, the white plastic pipe running outside is the condensate drain. If frozen, the boiler shuts down. Pour warm (not boiling) water over the outside section of the pipe, then reset the boiler.
Try the reset button
Hold the reset button (usually marked with a flame symbol) for 2–3 seconds. The boiler will attempt to relight. If it fires then cuts out within 5 minutes, there is a fault — call us.
Check your gas supply
Check that other gas appliances (hob, gas fire) work. If they don't, call Cadent (National Gas Emergency) on 0800 111 999. Also check your gas meter — if you have a prepayment meter, it may be out of credit.
Check the thermostat and timer
Ensure the room thermostat is set above the current room temperature and the programmer/timer is calling for heat. Smart thermostats can occasionally lose their settings after a power cut.
Common Boiler Breakdown Faults
| Symptom | Likely fault | Repair cost |
|---|---|---|
| No heat and no hot water | Diverter valve failure, PCB fault, or complete ignition failure | Diverter valve: £180–£280 · PCB: £250–£450 · Ignition: £120–£200 |
| No hot water but heating works | Diverter valve stuck in 'heating only' position | Diverter valve replacement £180–£280 |
| Boiler fires then cuts out | Overheat stat triggered, heat exchanger blocked, pump failure | Flush + pump replacement £180–£320 |
| Pilot light keeps going out | Faulty thermocouple, dirty pilot jet, draught problem | Thermocouple replacement £95–£150 |
| Boiler making banging/kettling noise | Sludge in heat exchanger, limescale build-up | Power flush £350–£550 · Heat exchanger replacement £400–£700 |
| Boiler leaking water | Pressure valve dripping, pump seal, or heat exchanger crack | PRV replacement £85–£150 · Pump seal £120–£180 · HX replacement expensive — assess for replacement |
Boiler Repair Prices — London 2026
| Repair | Time | Price |
|---|---|---|
| Boiler breakdown diagnosis | 1–2 hrs | £95–£120 |
| Ignition / pilot light repair | 1–2 hrs | £120–£200 inc. parts |
| Diverter valve replacement | 2–3 hrs | £180–£280 inc. part |
| Pump replacement | 1–2 hrs | £160–£280 inc. pump |
| PCB replacement | 1–2 hrs | £250–£450 inc. part |
| Gas valve replacement | 2–3 hrs | £200–£450 inc. part |
| Pressure relief valve (PRV) replacement | 1 hr | £85–£150 inc. part |
| Frozen condensate pipe thaw + reset | 30–60 min | £75–£95 |
Fixed quote after diagnosis. Gas Safe registered engineers. No call-out fee. 7 days a week.
Boiler Breakdown Cover Across London
Boiler Breakdown FAQs
How much does boiler breakdown repair cost in London?
Simple fixes like re-igniting the pilot light or resetting cost £95–£120. Diverter valve, pump, or PCB replacement costs £150–£450 including parts. Gas valve replacement is £200–£450. Fixed quote after on-site diagnosis.
Why has my boiler stopped working?
Most common causes: low pressure (check gauge — should read 1.0–1.5 bar cold), frozen condensate pipe (cold weather), ignition failure, PCB fault, pump failure, or diverter valve stuck. Check the pressure gauge and reset button first — this resolves ~30% of breakdowns without a call-out.
What should I do if I smell gas from my boiler?
Don't switch anything on or off. Open windows. Turn off gas at the meter (ECV). Leave the property. Call 0800 111 999 (National Gas Emergency, free 24/7). Do NOT call us first — safety first.
My boiler is showing a fault code — what does it mean?
Common codes: Worcester EA (ignition failure), E9 (overheat). Ideal F1 (low pressure), L2 (ignition). Vaillant F28 (gas), F29 (ignition). Baxi E168 (no gas), E119 (pressure). Call us with your make, model, and fault code for guidance.
Is it worth repairing or replacing my boiler?
Replace if: boiler >10 years old AND repair cost >£300, PCB failure on old boiler, 2+ breakdowns per year, or old G-rated efficiency. We give an honest on-site assessment — if replacement is better value, we'll say so.
How quickly can you respond to a boiler breakdown in London?
Same-day across all 33 boroughs. Central/inner London: typically 2–4 hours. Outer boroughs: 3–6 hours. Priority for properties with vulnerable residents. Call for an honest arrival time estimate.
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Boiler Broken Down? We'll Be There Today.
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