No Heating in London? 24/7 Emergency Heating Repair
No heating? Check the boiler pressure gauge, the thermostat and the timer first. Still cold? Our Gas Safe engineers diagnose and fix boiler, pump, zone valve and thermostat faults 24/7, with the price agreed before work starts.
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24/7 Emergency
Engineers available every day of the year
No Call-Out Fee Over 2hrs
£60 waived on jobs exceeding 2 hours
30-Day Guarantee
All repairs guaranteed in writing
Price first
Agreed before work starts
Priority
Vulnerable households
£0 call-out
Waived on jobs over 2 hours
24/7
All year including bank holidays
What We Check First When You Have No Heating
Before dispatching, we ask four questions that allow us to bring the right parts and diagnose faster:
- Is the boiler firing at all? — If it fires but produces no heat, the fault is downstream (pump, zone valve, valves). If it won't fire, it's likely a boiler fault, gas supply issue or thermostat wiring.
- Does hot water still work? — On a combi boiler, hot water and heating are separate circuits. HW working but no heating points to the zone valve or heat-only circuit. Neither working suggests a boiler-level fault.
- Is the boiler showing a fault code? — We interpret codes for all major brands on arrival. F22/F75 = pressure; F28/F29 = ignition; EA = lockout; H07 = pump.
- How old is the boiler and when was it last serviced? — This determines whether a repair is cost-effective or whether replacement makes more sense. We give honest advice.
With this information, our engineers arrive with the most likely replacement parts already on the van — dramatically reducing the chance of a second visit.
No Heating? Six Checks to Make Before You Call
A good share of no-heating calls turn out to be a setting or a supply problem rather than a broken part. These checks take a few minutes and are safe for anyone to do. None of them involve opening the boiler casing.
- Thermostat and programmer. Turn the room thermostat a few degrees above the current room temperature and make sure the programmer or timer is set to heating “on” or “constant”, not “off” or hot water only. After a power cut, many timers reset to the wrong time. A wireless thermostat with flat batteries will also stop calling for heat.
- Boiler pressure. Most sealed systems run at 1 to 1.5 bar when cold. Below about 0.5 bar the boiler locks out. Topping up is covered in our step-by-step guide to repressurising a boiler.
- Power to the boiler. Check the fused spur switch next to the boiler is on and the display is lit. If a fuse or trip in the consumer unit has gone, reset it once. If it trips again, leave it off and call us.
- Gas supply. Check the gas hob lights. If it doesn't, the problem is the supply or a prepayment meter out of credit, not the boiler. If you smell gas, leave the property and call the National Gas Emergency Service on 0800 111 999.
- Frozen condensate pipe. In a cold snap, a condensing boiler whose plastic condensate pipe runs outside can freeze and lock out, often with a gurgling noise. Pouring warm (not boiling) water along the outside section usually clears it. See our condensate pipe repair page if it keeps happening.
- One reset only. If the boiler shows a lockout, press reset once. If the same code returns, stop resetting and book an engineer. Our boiler error codes guide explains what the common codes mean.
Heating Off but Hot Water Working (or the Other Way Round)
Which half of the system still works tells us a lot. On a combi boiler, hot water working with no heating usually means the diverter valve, the pump or the heating demand from the thermostat. On a system or regular boiler with a hot water cylinder, a failed motorised zone valve is the usual suspect: one zone stays shut while the other works normally. If you have neither heating nor hot water, the fault is more likely at the boiler itself, the gas supply or the controls. When it is the hot water that has gone, our no hot water repair page covers that side of the problem.
No Heating in a Rented Flat or House
If you rent, repairs to the heating and hot water are normally your landlord's responsibility under Section 11 of the Landlord and Tenant Act 1985. Report the fault to your landlord or letting agent in writing (a text or email is fine) so there is a record, and say if anyone in the home is elderly, unwell or a young child. Landlords and agents can book us directly, and we can send the job sheet to them rather than to the tenant. Our guide on how to report a plumbing repair to your landlord covers what to include and the timescales to expect.
While you wait, keep one room warm with a plug-in heater, keep internal doors closed, and leave the loft hatch shut so pipes in the roof space don't get too cold. If radiators in only part of the house stay cold once the heating is back, that is usually a balancing or sludge issue rather than a breakdown: see cold radiator repair and power flushing.
No Heating Faults — Diagnosis & Typical Cost in London
| Option | Fault | Symptom | Typical Cost | Time on Site |
|---|---|---|---|---|
| Circulation pump seized | Boiler fires, no heat to radiators | £180–£350 | 1.5–2.5 hrs | |
| Zone valve failed | One zone (heating or HW) dead | £120–£250 | 1.5–2 hrs | |
| Thermostat fault | Boiler won't fire at all | £80–£180 | 1–1.5 hrs | |
| PCB (control board) | Multiple fault codes, intermittent | £200–£450 | 2–3 hrs | |
| Air in system | Some radiators cold at top | £90–£150 | 1–2 hrs | |
| Sludge blockage | All radiators cold or cold at bottom | £350–£600 (powerflush) | 4–6 hrs | |
| Low pressure lockout | Boiler lockout, F22/F75 code | £60–£120 | 0.5–1 hr |
London-Specific Data
Why London Properties Are Different
Winter peak
Heating failure callouts in London increase 4× in December and January vs summer. Early-morning callouts (6–9am) are highest — when occupants wake to a cold house.
12–20 years
Average age of boilers causing emergency no-heating callouts in London. Older boilers have a much higher fault rate — annual servicing reduces breakdown risk by 50%.
60% sludge
Of London heating systems showing poor performance contain significant magnetite (boiler sludge), particularly in properties with hard London water and original radiators.
4°C
Temperature at which frozen pipes become a serious risk in unheated London properties — particularly in loft tanks, external walls and condensate pipes. No heating in winter needs urgent attention.
From the Blog
Related Guides for London Homeowners
Coverage
We Cover All 33 London Boroughs
From Barnet to Bromley, Hillingdon to Havering — our engineers are based across London for rapid same-day response.
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Same-day engineers across all 33 London boroughs. Gas Safe registered. No call-out fee on jobs over 2 hours.