A boiler service is an annual inspection, clean and performance check carried out to the manufacturer's instructions by a Gas Safe registered engineer. It keeps the boiler running efficiently, supports the warranty and catches worn parts before they fail. BritCertify services boilers across London for £159 inc. VAT including a gas safety certificate, and diagnoses and quotes for repairs before any work starts.
What does a boiler service include?
A boiler service is an inspection, clean and performance check carried out to the manufacturer’s service instructions. Where a gas safety check confirms an appliance is safe on the day, a service keeps it running efficiently and finds worn components before they fail.
| Stage | What our engineer does |
|---|---|
| Visual inspection | Checks the casing, seals, flue route and terminal, condensate pipe and any signs of leaks, scorching or water damage |
| Combustion analysis | Uses a flue gas analyser and compares the readings with the manufacturer’s figures |
| Internal checks | Removes the case where the instructions require, then inspects and cleans the burner, heat exchanger, electrodes and condensate trap |
| Gas supply | Checks operating pressure and gas rate |
| Safety devices | Confirms ignition, flame detection and the pressure relief valve work as designed |
| System checks | Checks system pressure, the expansion vessel charge where accessible, and the operation of controls and thermostats |
The results go into the service record section of the Benchmark checklist in your boiler manual, which manufacturers look for if you ever make a warranty claim. Gas work is carried out by Gas Safe registered engineers (Gas Safe reg. 962998). Always ask to see the engineer’s Gas Safe ID card.
Is a boiler service the same as a gas safety certificate?
No, and landlords in particular need to know the difference. The gas safety check required by regulation 36 of the Gas Safety (Installation and Use) Regulations 1998 confirms that appliances, fittings and flues are safe to use, and it is a legal duty every 12 months. A service is maintenance: it is not a legal requirement, but most manufacturers make an annual service a condition of their warranty.
Our £159 inc. VAT price covers both the boiler service and a gas safety certificate, completed on one visit. Homeowners get the same checks, which gives you a useful record if you later sell or let the property. The HSE’s guidance for landlords explains the gas safety duty in full.
How often should a boiler be serviced?
Once every 12 months is the standard recommendation, whether you live in the property or let it. Booking in late summer or early autumn means faults are found before the heating is needed every day.
Landlords can line the service up with the gas safety check. A check carried out up to 2 months before the deadline keeps the original expiry date, so the two can be combined without shortening the certificate year. If a boiler has gone several years without a service, expect the first visit to take longer and to uncover more wear, particularly blocked condensate traps and dirty heat exchangers.
What boiler faults do our engineers repair?
The repair calls we attend usually start with one of a handful of symptoms. The table shows the common causes and what you can safely check before calling us.
| Symptom | Common causes | What you can check first |
|---|---|---|
| Pressure keeps dropping | A leak on the system, a failing pressure relief valve or an expansion vessel that has lost its charge | Look for drips at radiator valves and visible pipework, then repressurise as the manual describes |
| Boiler locks out in freezing weather | A frozen condensate pipe outside the property | Pour warm, not boiling, water over the external pipe, then reset the boiler |
| No ignition or repeated lockouts | Gas supply problem, ignition electrode, fan or flue fault | Check other gas appliances work and, on a prepayment meter, that there is credit |
| Heating works but no hot water (combi) | Diverter valve, flow sensor or a scaled plate heat exchanger | Check the hot water setting on the boiler and on your controls |
| Kettling or banging noises | Limescale or sludge in the heat exchanger, or a pump fault | Nothing to check yourself; book a diagnosis |
Never remove the boiler casing yourself. If you ever smell gas, call the National Gas Emergency Service on 0800 111 999 straight away.
How are boiler repairs priced?
We diagnose the fault first and give you a fixed repair price before any work starts. Repairs are quoted after diagnosis because the same symptom can have very different causes: low pressure might be a weeping radiator valve or a failed expansion vessel.
If a part has to be ordered, we leave the boiler safe, explain the timescale and return to fit it. Where a boiler is old, parts are discontinued or the heat exchanger itself has failed, a repair may not be good value. In that case we give you the repair price alongside the option of a boiler replacement, so you can compare the two honestly.
What should landlords do when a tenant reports a boiler fault?
Act quickly and keep a written record. Heating and hot water are basic repairs that landlords are expected to deal with promptly, and a breakdown is hardest on tenants in winter or where someone in the household is vulnerable.
Ask the tenant for any error code on the display, whether the pressure gauge reads low and whether other gas appliances still work. That information often lets our engineer arrive with the likely part. If the boiler has been turned off and labelled as unsafe, it must not be used until it is repaired and re-checked, so arrange temporary heating in the meantime and confirm the repair date to the tenant in writing.
What do we see on London boilers?
- Frozen condensate pipes: combi boilers in flats with condensate pipes running down an exposed external wall, which freeze in a cold snap and lock the boiler out.
- Limescale: London’s hard water builds scale in combi heat exchangers, which often shows up first as hot water that swings between hot and cold.
- System sludge: older radiators in Victorian and Edwardian houses shed sludge into the boiler, especially where no magnetic filter has been fitted.
- Difficult access: boilers in the lofts of converted houses without a fixed ladder, boarding or lighting, and boilers in tight mansion block cupboards. The engineer needs safe access to work, so please sort this before the visit.
How should you prepare for a service or repair?
- Clear the boiler cupboard and make sure the flue route can be seen, including any boxing in ceilings.
- Find the boiler manual so the Benchmark service record can be completed.
- For repairs, note any error code on the display and when the fault happens.
- Landlords: give tenants written notice, and consider our landlord gas and electrical bundle if the EICR is also due.
Boiler service and repair prices in London (inc. VAT)
| Option | Price (inc. VAT) | Notes |
|---|---|---|
| Boiler service with gas safety certificate | £159 | Service and landlord gas safety record on one visit |
| Boiler repair | Quote | Fixed price given after diagnosis, before work starts |
Prices include VAT. Repairs are quoted after diagnosis, before any work starts. Central London parking or Congestion Charge may be added; we always confirm before booking.
Book this serviceWhat's included
- Boiler inspection and service to the manufacturer's instructions
- Flue gas analysis and safety device checks
- Condensate trap and pipe checked
- Gas safety certificate included in the £159 price
- Benchmark service record completed
- Fixed repair quote before any work starts
How it works
Book
Tell us the boiler make, model and location, and whether you need a gas safety certificate. For repairs, describe the fault and any error code.
Inspect and test
A Gas Safe registered engineer inspects, cleans and tests the boiler to the manufacturer's instructions, including flue gas analysis.
Diagnose and quote
If a fault is found, we explain the cause and give a fixed repair price before any work starts.
Records issued
You receive a service record, the Benchmark entry in your manual and, where booked, the gas safety record the same day.
Boiler Service & Repair: frequently asked questions
How much does a boiler service cost in London?
A boiler service with BritCertify costs £159 inc. VAT and includes a landlord gas safety certificate, completed on the same visit. Repairs are quoted after diagnosis, before any work begins, so you know the price in advance. Central London parking or Congestion Charge may be added; we always confirm before booking.
How long does a boiler service take?
A routine service on an accessible boiler is normally completed within a single short visit. It takes longer when the boiler sits in a loft or a tight cupboard, when it has not been serviced for several years, or when the gas safety check covers several appliances. We give you an arrival window when you book.
Does missing a service affect my boiler warranty?
It can. Most manufacturers' warranties require an annual service by a Gas Safe registered engineer, recorded in the Benchmark section of the boiler manual. If a service is missed, the manufacturer may refuse a warranty claim. Keep the manual and all service records together, and book the service around the same time each year.
Why does my boiler keep losing pressure?
Usually because water is escaping from the system or the pressure is not being held. Common causes are a slow leak at a radiator valve or joint, a pressure relief valve that is letting water by, or an expansion vessel that has lost its charge. Repressurise as the manual describes, and book a repair if it drops again within days.
Is it worth repairing an old boiler?
Often, if the fault is a single component and parts are readily available. Replacement becomes the better option when parts are discontinued, faults keep recurring or the heat exchanger has failed. Our engineer will give you a fixed repair price and, where it makes sense, a replacement quote, so you can compare the two before deciding.
What should I do if I smell gas?
Act straight away. Open doors and windows, turn off the gas at the meter if you can do so safely, avoid using electrical switches or naked flames, and call the National Gas Emergency Service on 0800 111 999. Once the emergency service has made the supply safe, a Gas Safe registered engineer can trace and repair the fault.
Sources and official guidance
Written and checked by the BritCertify technical team. Last reviewed 6 October 2026.