F22
Vaillant
Low water pressure, system below 0.5 bar
You can try repressurising to 1.5 bar via the filling loop. If it drops again within days, there's a leak, book an engineer.
24/7 Emergency Line, engineers on standbyAll 32 London boroughs
Gas Safe Registered12-month guarantee · No call-out fee
24/7 EMERGENCY LINE, LIVEBoiler broken?
Boiler broken?
A Gas Safe engineer at your door within the hour.
Same-day repairs across all 32 London boroughs. Fixed prices agreed before work begins. Fully insured, DBS-checked, and backed by a 12-month workmanship guarantee.
- 60–90 minResponse
- £0Call-out
- 12 moGuarantee
- 4.9 / 51,200+ jobs
Engineers online now
24/7Get a free callback
Average reply under 10 minutes. No obligation.
Call 020 3000 0000or request callback
Gas Safe
1-hour response
No call-out fee
Gas Safe Registered
Reg. No. XXXXXX
£2m Public Liability
Fully insured
4.9 / 5 rating
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DBS Vetted
All engineers
12-month guarantee
On every repair
Our Services
Everything your boiler needs, from one team.
Repair, service, install or certify, handled by London-based Gas Safe engineers using genuine parts.
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24/7
Emergency Boiler Repair
24/7 response to no heat, leaks and breakdowns.
Learn more£85–120
Boiler Servicing
Full annual service to manufacturer specification.
Learn moreA-rated
Boiler Installation
New A-rated combi & system boilers, fitted next day.
Learn moreB2B
Commercial Boilers
Landlords, offices, restaurants, HMOs.
Learn moreSame day
Gas Safety (CP12)
Same-day certificates for landlords.
Learn moreFull system
Central Heating Repair
Radiators, pumps, valves, controls.
Learn morePer system
Power Flushing
Clears sludge, restores efficiency & warmth.
Learn moreFrom £12/mo
Annual Cover Plans
Priority response and included servicing.
Learn moreDiagnostic Reference
Recognise your boiler's symptom.
A page from our service manual. Match the readout to the symptom, then jump straight to a fix.
Readout
Symptom
Likely cause
Action
HEAT --
No heating or hot water, the classic emergency; house cold, taps cold.
Failed diverter valve, broken diaphragm, airlock or thermostat fault.
0.4 BAR
Boiler losing pressure, repressurising every few days just to keep it running.
Small leak in pipework, failing pressure relief valve or waterlogged expansion vessel.
LEAK
Boiler leaking water, drips or pooling under the unit. Never ignore it.
Corroded internals, failed seals or excess pressure, escalates fast into water damage.
IGN LOCK
Boiler not igniting, clicking but never firing up.
Faulty electrodes, gas supply issues, blocked burner or failed fan.
dB+
Banging, whistling, gurgling, kettling noises from the unit or pipes.
Limescale or sludge on the heat exchanger, common in London's hard water.
F.22
Error code on display, Vaillant, Worcester, Baxi, Ideal codes.
Each code maps to a specific fault, see the code lookup below.
-2°C
Frozen condensate pipe, the number-one cause of winter breakdowns.
External pipe freezes in cold snaps and shuts the boiler down.
RAD ▒▒
Radiators not heating up, cold at top, bottom, or whole rooms cold.
Top-cold = trapped air; bottom-cold = sludge.
Not sure what's wrong? Describe the symptom on the phone, we'll tell you honestly whether it's a repair, a service, or free advice.
Error Code Lookup
What's your boiler showing?
Type the error code on your display, we'll tell you what it means and how urgent it is.
MEDIUM
F28
Vaillant
Ignition failure, boiler won't light
Check other gas appliances work. If they do, the fault is internal (electrodes, gas valve, PCB), needs a Gas Safe engineer.
F75
Vaillant
Pump or pressure sensor fault
A restart may clear it once, but a recurring F75 means the pump or sensor is failing. Book before it becomes a full breakdown.
F29
Vaillant
Flame loss during operation
Often gas supply or flue related. Do not keep resetting, book an engineer.
EA
Worcester Bosch
Ignition/flame detection fault
Try one reset. If EA returns, the boiler is locked out for safety, Gas Safe engineer required.
E9
Worcester Bosch
Overheat, flow temperature too high
Usually a pump, blockage or heat exchanger issue. Switch off and book, repeated overheating damages the boiler.
E119
Baxi
Low system pressure
Repressurise to 1–1.5 bar. Recurring E119 = leak somewhere in the system. We trace it rather than topping up forever.
E133
Baxi
Gas supply or ignition failure
Check your gas meter/prepay credit and other appliances first. Still showing? Engineer needed.
F1
Ideal
Low water pressure
Repressurise via the filling loop to ~1.5 bar. If it keeps dropping, book a leak trace.
F2
Ideal
Flame loss
The boiler lit, then lost the flame. Gas supply, condensate or sensor fault, Gas Safe engineer required.
L2
Ideal
Ignition lockout
Often follows a frozen condensate pipe in winter. If pipes aren't frozen, the fault is internal, book a visit.
F.4
Glow-worm
Flame not detected
One reset maximum. Recurring F.4 needs electrode/PCB investigation by an engineer.
Different code or different brand? Call 020 3000 0000 and read it to us, we'll tell you over the phone what it means, free.
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How it works
From phone call to fixed, in four clear steps.
No hidden fees, no runaround. Over 85% of London repairs closed on the first visit.
- 011 min
Call or book
Speak to a real person 24/7. We confirm an arrival window before you hang up.
- 0260–90 min
Engineer dispatched
The nearest Gas Safe engineer is routed to your door, typically 60–90 minutes.
- 0315 min
Diagnose & fixed quote
Fault identified and explained. Fixed price agreed before any work begins.
- 041–2 hr
Repair, test, guarantee
Genuine parts, full safety test, 12-month workmanship guarantee.
Live · Recent jobs, London network
14:22, Diverter valve replaced · Hackney E8 · ✓ FIXED
Brand Register
Every marque, every model, repaired in London.
Worcester Bosch
Greenstar range: ignition faults, low-pressure lockouts, diverter valves.
EAE9
Vaillant
ecoTEC and ecoFIT: pressure faults, ignition lockouts, pump/sensor errors.
F.22F.28F.75
Baxi
Duo-tec, Platinum, 800 series: gas supply and low-pressure faults.
E133E119
Ideal
Logic, Vogue, Mexico: low pressure, flame loss, ignition faults.
F1F2L2
Glow-worm
Energy, Flexicom, Ultracom: leaks, ignition faults, error codes.
F.1F.4
Viessmann
Vitodens 050/100/200: sensor faults, ignition and pump issues.
F2F4
Potterton
Promax, Titanium, Suprima: ignition and PCB faults.
E168
AlphaFerroliMainVokèraRavenheat
Older or less common? If it burns gas and heats a London home, we repair it.
Transparent Pricing
Fixed prices agreed before we start.
Real London ranges, never teaser rates. Out-of-hours may add a modest premium, always disclosed upfront.
Job
Typical range
Notes
Diagnostic visit
£0 – £75
Waived when you proceed
Minor repair
£95 – £180
Most common jobs
Diverter valve replacement
£180 – £350
Parts + labour
Pump replacement
£200 – £350
Parts + labour
Fan replacement
£220 – £400
Parts + labour
PCB replacement
£300 – £500
Manufacturer part
Annual boiler service
£85 – £120
Full inspection
Power flush (up to 8 rads)
£350 – £600
Chemical + magnetic
Gas Safety Certificate (CP12)
£75 – £120
Same-day issue
No call-out fee · No hidden extras · Fixed quote before work
Get exact quoteHonest Reckoner
Repair it, or replace it?
Thirty seconds of honesty before you spend anything.
New20+ yrs
£50£1,000
REPAIR
Still economical. But start budgeting: boilers this age average one repair a year from here.
Rule of thumb: if the repair costs more than half a new boiler and yours is over 12 years old, replacement usually wins. Our engineers give you the honest numbers on site, the decision is always yours.
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Coverage
All 32 London boroughs, one phone number.
Regional teams organised so response times stay short, even on the coldest nights.
Postcode Checker
Are we covering your street tonight?
Region
North London
Barnet, Enfield, Camden, Islington, Haringey
N1N4N7N16N22NW1NW3NW6NW11EN1
Region
South London
Croydon, Bromley, Sutton, Wandsworth, Lambeth, Lewisham
SE1SE15SE22SE28SW11SW16SW20CR0BR1
Region
East London
Hackney, Tower Hamlets, Newham, Waltham Forest
E1E8E14E17E20IG1RM1
Region
West London
Hammersmith, Kensington, Ealing, Hounslow, Hillingdon
W1W6W11W14UB1TW1
Region
Central London
Westminster, the City, Southwark
EC1EC2EC4WC1WC2SW1SE1
What Londoners say
Rated 4.9 / 5 across 1,200+ jobs.
"Called at 11pm on a Sunday, engineer at the door by 12:30. Diagnosed a failed diverter valve, fixed by 2am. Genuinely lifesaved us before a newborn came home."
Sarah M.
N1 · Islington
"Fixed price given on the phone, no upsell, no drama. Boiler back on within 90 minutes. Best trades experience I've had in London."
David P.
SW11 · Battersea
"Landlord CP12 issued same day, engineer polite and thorough. Tenants happy, that's all I needed."
A. Patel
E14 · Canary Wharf
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Gas Safe ID · photo required
ENGINEER STANDARDS
The person who turns up matters.
Every engineer in our network carries a Gas Safe ID card with their photo, licence number and the work they're qualified for. Check it at the door, they'll expect you to.
You can verify any engineer independently in 30 seconds at gassaferegister.co.uk. No ID, no entry: that's the rule we tell our own customers to follow.
Gas Safe ID carriedDBS-checkedUniformed & insured
LANDLORDS · CP12
Gas Safety Certificates, issued the same day.
We handle Landlord Gas Safety Records (CP12) for portfolios of every size across London, flats, HMOs, and blocks. Tenants notified, records digital, always compliant.
- Same-day appointments, evenings & weekends
- Digital records emailed within the hour
- Portfolio pricing for 3+ properties
- Combined service + CP12 discount
Landlord Gas Safety Record
CP12 · SPECIMEN
GAS SAFE
- Property
- Flat 4, 22 Example St, E1
- Appliance
- Worcester 30i · Combi
- Location
- Kitchen
- Flue type
- Room-sealed
- Op. pressure
- 20 mbar ✓
- CO reading
- 0 ppm ✓
- Safety devices
- Operational ✓
- Overall status
- SAFE TO USE
Reg. No. XXXXXXIssued: today
FAQ
Straight answers to the questions we hear every day.
Yes. Phones are answered 24 hours a day, seven days a week, including bank holidays. Engineers are on rotation across London every night.
No. We do not charge to attend. You only pay for the diagnostic (£0–£75, waived when you proceed) and the agreed fixed-price repair.
Typical response is 60–90 minutes for emergency calls within Greater London. During cold snaps we prioritise no-heat and vulnerable-household jobs.
Every engineer on the network is Gas Safe registered, DBS-checked and carries their ID card. You can verify our registration on the Gas Safe Register.
All major UK brands, Worcester Bosch, Vaillant, Baxi, Ideal, Glow-worm, Viessmann, Potterton, Alpha, Ferroli, Main, Vokèra and more.
A 12-month workmanship guarantee on every repair. Parts carry the manufacturer's own warranty on top.
Yes. After diagnosis we give a fixed written quote before any work begins. No hourly surprises.
Yes, usually same-day. Digital copy emailed within the hour of completion.