How Much Does an Emergency Boiler Repair Cost?

What you are actually paying for

Most people ring for a price and get a number that turns out to be only the first line of the bill. Knowing how the bill is built lets you compare firms properly before anyone sets off.

The call-out covers getting an engineer to your door and, with many firms, the first 30 to 60 minutes on site. Labour is charged after that, either by the hour or as a fixed price per job. The part is priced separately, and for boiler parts the markup varies a lot between firms. Out of hours, one or more of those three lines goes up, and it is not always the one you were quoted.

So when you ask about cost at 10pm, the useful questions are: what is the call-out, what does it include, is labour hourly or fixed, and is there a night or weekend rate on top.

Typical London call-out and labour rates at night and weekends

These are rough market ranges drawn from published UK price guides, which vary a lot between sources, with London sitting at the upper end. They describe what the market charges, not our prices.

• Weekday daytime attendance: roughly £60 to £150 for the first half hour or hour on site.
• Evenings, nights and weekends: commonly £100 to £250 for the first hour, then an hourly rate.
• Bank holidays and the small hours: usually the dearest slot, at the top of that range or above it.
• Hourly labour in London after that first period: roughly £75 to £120 during the day, and more at night with firms that charge a premium.

Ours is simpler. The £60 call-out is the same at 3am on a Sunday as at noon on a Tuesday, and the repair price is agreed with you on site before any work starts. The pricing page sets it out.

What the common night-time repairs cost fitted

Once the engineer has found the fault, the repair itself is usually one part plus the time to fit it and test the boiler. Rough fitted prices from published UK guides, parts and labour together, with London towards the top of each range:

• Ignition electrode or flame sensor, a common cause of a boiler that tries to light and locks out: roughly £100 to £200.
• Temperature sensor (thermistor): roughly £100 to £200.
• Water pressure sensor: roughly £120 to £250.
• Fan assembly: roughly £200 to £450.
• Diverter valve on a combi, the usual cause of heating but no hot water or the reverse: roughly £200 to £400.
• Pump: roughly £200 to £450.
• Printed circuit board: roughly £350 to £700.
• Gas valve: roughly £200 to £500.
• Primary heat exchanger: from roughly £500 to well over £1,000, which is where repair or replace becomes a real question.

Why a night repair can cost more than the part suggests

Merchants are shut. At night the engineer can only fit what is on the van. Fast-moving parts for the big brands, such as electrodes, sensors, pumps and diverter cartridges for popular Worcester Bosch, Vaillant, Baxi and Ideal models, are often carried. A board or gas valve for a less common boiler usually is not. That means a make-safe visit tonight and a return visit when the part arrives, and some firms charge a second call-out for it. Ask before you book.

The system needs draining. A pump or heat exchanger usually means draining the heating, refilling, bleeding and repressurising it. That can add an hour or more of labour.

The fault is not the first one you see. A boiler that has lost pressure may have a leaking relief valve because the expansion vessel has gone flat. Fixing only the symptom brings the engineer back the next week. A sensible engineer will explain the chain and price both parts together.

The boiler is old. Some models are out of production and parts come from specialist suppliers, which costs more and takes longer. If the fault turns out to be the heat exchanger, see whether to repair or replace a broken boiler before you agree to anything.

Checks that can save you the call-out

Low pressure, a one-off lockout, a frozen condensate pipe and a tripped fuse spur all stop a boiler, and you can clear each of them without paying anyone. Run through these first, all outside the boiler casing:

• Pressure gauge below about 1 bar: top up at the filling loop, then reset once. Boiler pressure at zero shows how.
• Fault code or lockout light: press reset once. If it locks out again, leave it.
• Frost outside: thaw the condensate pipe with warm water.
• No display at all: check the fused spur switch next to the boiler and the fuse box.
• Prepayment gas meter: check there is credit and the emergency credit has not run out.

If you smell gas, open windows, shut the gas off at the meter if safe, avoid switches and call 0800 111 999 from outside. Do not operate switches or the boiler.

Before you call anyone, check who should be paying

A boiler still under the manufacturer’s warranty, commonly 5 to 10 years on newer models and up to 12 on some, as long as it was registered and has been serviced every year, should go to the manufacturer first. Most warranties only pay for repairs by the manufacturer’s own engineers, so check before you book anyone else.

If you pay for home emergency or boiler cover, check the excess and whether night call-outs are included. Whether home emergency cover is worth it compares typical policies against paying per job.

Tenants should report to the landlord in writing. Under section 11 of the Landlord and Tenant Act 1985, which covers most tenancies of under seven years, the landlord is responsible for keeping the installations for heating and hot water in repair, and should pay unless the tenant caused the damage.

What a £60 call-out gets you tonight

An engineer at your door any hour of the day or night, anywhere in London and inside the M25, to find the fault and make the boiler safe. The repair price is agreed with you on site before any work starts, so you know the full cost before you say yes.

Gas work is carried out by Gas Safe registered engineers. If the part is on the van, the repair can often be done on the same visit; if it needs ordering, ask for the return visit to be booked before the engineer leaves. For what the visit covers, see emergency boiler repair, or boiler repairs if it can wait until daytime.