By Emily Rivers
Last updated 14th January 2025

The cost of repairing your boiler when your boiler is not working varies because of the number of boiler components that  might require replacing to get your boiler working again. It might be a simple case of repressurise your boiler combi boiler which you can do yourself or a more costly heat exchanger replacement.

Common boiler repairs Cost
Replace heat exchanger £400
Replace diverter valve £187
Replace automatic air vent £98
Replace pressure relief valve (PRV) £101
Replace printed circuit board (PCB) £268
Replace boiler circulator pump £225
Average boiler repair cost £213

Repair: Cost to replace a heat exchanger

The boiler repair costs to replace a heat exchanger (main, domestic and condensing) average £400

Gas and oil boilers burn fuel to create a flame which heats the outside metal surface of a main heat exchanger. The heat from the flame transfers through the metal to the inside of the main heat exchanger to heat the water which circulates around pipes and radiators, through the heating coil of a hot water cylinder.

If you have a combination boiler the same heating water can be sent inside your boiler, via a diverter valve, to a secondary smaller domestic heat exchanger to heat the clean domestic hot water for your taps.

Condensing boilers have another heat exchanger which recycles energy from flu gases to improve the overall energy efficiency of the boiler.

If the heat exchanger is faulty you may notice banging or whistling noises coming from the boiler. The boiler might start leaking or rattle and the boiler performance will be degraded. 

Repairing a heat exchanger is possible if it is a lime scale problem where it just requires cleaning. If its cracked or damaged the exchanger needs replacing and at this point you need to decide if you need a new boiler.

If the boiler is over 10 years old it might be more cost effective to look at other options. If it's newer you should be able to get a replacement under manufacturers warranty.

Either way our Gas Safe members are waiting to help you repair your heat exchanger, just click "Get quotes" and describe your job.

Boiler repair cost

Cost to replace a boiler diverter valve

The boiler repair costs to replace a boiler diverter valve average £187

Diverter valves are part of a combination boiler and they control whether hot water is used to heat radiators or the domestic hot water that comes out of taps (by diverting hot water to a secondary domestic heat exchanger).

When the central heating system is calling for heat the diverter valve will direct the heating water into the heating flow pipe, towards the central heating radiators and then back via the heating return pipe back to the boiler.

When a hot water tap or shower is turned on a flow sensor will tell the boiler that hot water is required. The boiler will change the diverter valve position closing flow to the heating pipes and opening flow to the domestic hot water heat exchanger.

The hot water in the boiler enters the domestic heat exchanger and heats the metal plate to plate structure. Clean cold domestic mains water enters the domestic heat exchanger passing through alternate plates ie not mixing with the heating water. The clean water is instantly heated and pushed along under mains pressure out of the boiler towards the open hot water tap or shower.

If the diverter valve fails you should get a system warning on the boiler and either no hot water or no heating. Some boilers automatically shut down as a safety precaution. You might also get a leak or banging noise coming from the boiler.

Reparing a faulty diverter valve can take a couple of hours by replacing the component if its less than 10 years old. If the e heating engineer identifies an underlying issues with system, including corrosion, you may need a powerflush.

Always get a Gas Safe heating engineer to replace component on you heating system. Our engineers are gas safe and price competitive. Click "Get quotes" and describe your job.

Cost to replace an automatic air vent

The boiler repair costs to replace an automatic air vent average £98

When air enters or gases generate inside a heating system various problems can occur. Air locks can reduce heating water flow rates causing the temperature inside the boiler to increase and boilers turning off. Other problems can be corrosion and noises.

Manually removing these unwanted gases is difficult and costly in labour and so automatic air vents are used. Automatic air vents can be fitted along heating system pipework, integrated into circulator pumps, system filters or fitted as a planned component inside the boiler.

Automatic air vents generally operate using a float with when in air/gas drops to open a valve and releases the gas which is pushed out by the water pressure. Once the float in surrounded by water it lifts up and closes the valve.

To repair an automatic air vent it needs a replacement part fitted by a gas safe engineer in your area. Click "Get quotes" to post your job and quickly get the best price.

Cost to replace a pressure relief valve

The boiler repair costs to replace a pressure relief valve (PRV) average £101

PRV stands for pressure relief valve and they are a safety release valve present to prevent pressure building up to a dangerous level. If pressure built up in a boiler to a dangerous level the PRV would open and release the pressure via a pipe which goes through an external wall to outside the building (turned back onto the wall so as not to burn anyone). Once the pressure has dropped the valve automatically closes.

Most PRVs use a spring to push closed a valve holding back water pressure until pressure builds enough to over power the spring at a pre calibrated pressure. Water will then pass by the valve, the system pressure will drop and the PRV spring will then reassert itself to close the valve.

To repair a pressure relief valve you need to replace it with a new component. Prices depend on the boiler installed.

Cost to replace a printed circuit board

The boiler repair costs to replace a printed circuit board (PCB) average £268

PCBs are the electronic control centre of your boiler which communicate with all the sensors monitoring temperature and pressures before sending instructions to motors ensuring the boiler runs safely and efficiently.

  • Common PCB problems
  • Intermittent display panel operation
  • Smell of burning
  • No power light
  • Boiler functions sporadically

The biggest cause of PCB failures is water or even water vapour coming into contact with the sensitive electrical wiring or components on a PCB. Cracks or faulty connections can exist but a leak or operation spill if more likely.

Repair costs depend on the cost of the printed circuit board, if it is water damaged, and the heating engineers time. Our engineers are experienced with competitive rates.   

Cost to replace a boiler circulator pump

The boiler repair costs to replace a boiler circulator pump average £225

Your boiler circulatory pump (probably made by Grundfos) pushes the hot water through your boiler and around your central heating system. Combi and system boilers usually contain pumps while some other boilers may have circulation pumps outside the boiler on the large primary pipework.

Possible causes of pump failures

  • If the pump becomes air locked it could overheat and then the plastic impeller inside may warp and get jammed.
  • If corrosion debris is present then the impeller can become clogged and over time lose efficiency.
  • Corrosion could cause a leak at the connection to pipes and then lead to an electrical fault.

If the pump is faultly you will get a system fault on your boiler that probably won't fire up. If you listen to your pump it might make a new buzzing noise or no noise at all.

Reparing a faulty or warn pump means replacement and costs depend on the condition of your pipework and flange fittings. If you have a very old system, new pumps might require additional pipework and wiring modifications.


Estimates for common heating engineer jobs;

Rates for other trades

Boiler repair cost in the UK
Boiler repair cost in the UK (excluding VAT or callout charges)
Location in UKBoiler repair cost
Boiler repair near London£240
Boiler repair near Birmingham£204
Boiler repair near Leeds£198
Boiler repair near Glasgow£208
Boiler repair near Sheffield£200
Boiler repair near Bradford£200
Boiler repair near Liverpool£206
Boiler repair near Edinburgh£208
Boiler repair near Manchester£204
Boiler repair near Bristol£202
Boiler repair near Kirklees£198
Boiler repair near Fife£204
Boiler repair near Wirral£204
Boiler repair near North Lanarkshire£208
Boiler repair near Wakefield£200
Boiler repair near Cardiff£196
Boiler repair near Dudley£204
Boiler repair near Wigan£204
Boiler repair near East Riding£196
Boiler repair near South Lanarkshire£206
Boiler repair near Coventry£204
Boiler repair near Belfast£188
Boiler repair near Leicester£202
Boiler repair near Sunderland£208
Boiler repair near Sandwell£204
Boiler repair near Doncaster£200
Boiler repair near Stockport£204
Boiler repair near Sefton£204
Boiler repair near Nottingham£200
Boiler repair near Newcastle Upon Tyne£208
Boiler repair near Kingston-upon-Hull£196
Boiler repair near Bolton£204
Boiler repair near Walsall£204
Boiler repair near Plymouth£190
Boiler repair near Rotherham£198
Boiler repair near Stoke-on-Trent£202
Boiler repair near Wolverhampton£206
Boiler repair near Rhondda, Cynon, Taff£196
Boiler repair near South Gloucestershire£204
Boiler repair near Derby£202
Boiler repair near Swansea£198
Boiler repair near Salford£204
Boiler repair near Barnsley£198
Boiler repair near Tameside£204
Boiler repair near Oldham£202
Boiler repair near Trafford£204
Boiler repair near Aberdeen£198
Boiler repair near Southampton£210
Boiler repair near Highland£192
Boiler repair near Rochdale£202
Boiler repair near Solihull£204
Boiler repair near Gateshead£208
Boiler repair near Milton Keynes£222
Boiler repair near North Tyneside£208
Boiler repair near Calderdale£198
Boiler repair near Northampton£218
Boiler repair near Portsmouth£210
Boiler repair near Warrington£206
Boiler repair near North Somerset£200
Boiler repair near Bury£202
Boiler repair near Luton£228
Boiler repair near St Helens£204
Boiler repair near Stockton-on-Tees£204
Boiler repair near Renfrewshire£206
Boiler repair near York£194
Boiler repair near Thamesdown£220
Boiler repair near Southend-on-Sea£214
Boiler repair near New Forest£210
Boiler repair near Caerphilly£194
Boiler repair near Carmarthenshire£190
Boiler repair near Bath£204
Boiler repair near Wycombe£234
Boiler repair near Basildon£218
Boiler repair near Bournemouth£208
Boiler repair near Peterborough£206
Boiler repair near North East Lincolnshire£194
Boiler repair near Chelmsford£218
Boiler repair near Brighton£220
Boiler repair near South Tyneside£208
Boiler repair near Charnwood£202
Boiler repair near Aylesbury Vale£224
Boiler repair near Colchester£214
Boiler repair near Knowsley£206
Boiler repair near North Lincolnshire£194
Boiler repair near Huntingdonshire£210
Boiler repair near Macclesfield£202
Boiler repair near Blackpool£198
Boiler repair near West Lothian£214
Boiler repair near South Somerset£190
Boiler repair near Dundee£208
Boiler repair near Basingstoke & Deane£240
Boiler repair near Harrogate£198
Boiler repair near Dumfries & Galloway£186
Boiler repair near Middlesbrough£204
Boiler repair near Flintshire£198
Boiler repair near Rochester-upon-Medway£204
Boiler repair near The Wrekin£204
Boiler repair near Newbury£238
Boiler repair near Falkirk£210
Boiler repair near Reading£238
Boiler repair near Wokingham£238
Boiler repair near Windsor & Maidenhead£236
Boiler repair near Maidstone£216
Boiler repair near Redcar & Cleveland£204
Boiler repair near North Ayrshire£200
Boiler repair near Blackburn£198
Boiler repair near Neath Port Talbot£200
Boiler repair near Poole£208
Boiler repair near Wealden£218
Boiler repair near Arun£216
Boiler repair near Bedford£220
Boiler repair near Oxford£218
Boiler repair near Lancaster£200
Boiler repair near Newport£194
Boiler repair near Canterbury£214
Boiler repair near Preston£200
Boiler repair near Dacorum£232
Boiler repair near Cherwell£218
Boiler repair near Perth & Kinross£198
Boiler repair near Thurrock£222
Boiler repair near Tendring£232
Boiler repair near Kings Lynn & West Norfolk£192
Boiler repair near St Albans£234
Boiler repair near Bridgend£196
Boiler repair near South Cambridgeshire£214
Boiler repair near Braintree£214
Boiler repair near Norwich£208
Boiler repair near Thanet£212
Boiler repair near Isle of Wight£210
Boiler repair near Mid Sussex£226
Boiler repair near South Oxfordshire£230
Boiler repair near Guildford£236
Boiler repair near Elmbridge£240
Boiler repair near Stafford£202
Boiler repair near Powys£208
Boiler repair near East Hertfordshire£226
Boiler repair near Torbay£200
Boiler repair near Wrexham Maelor£202
Boiler repair near East Devon£192
Boiler repair near East Lindsey£194
Boiler repair near Halton£204
Boiler repair near Warwick£206
Boiler repair near East Ayrshire£200
Boiler repair near Newcastle-under-Lyme£202
Boiler repair near North Wiltshire£214
Boiler repair near South Kesteven£202
Boiler repair near Epping Forest£238
Boiler repair near Vale of Glamorgan£200
Boiler repair near Reigate & Banstead£238
Boiler repair near Chester£204
Boiler repair near Mid Bedfordshire£222
Boiler repair near Suffolk Coastal£246
Boiler repair near Horsham£230
Boiler repair near Nuneaton & Bedworth£206
Boiler repair near Gwynedd£180
Boiler repair near Swale£212
Boiler repair near Havant & Waterloo£210
Boiler repair near Teignbridge£198
Boiler repair near Cambridge£210
Boiler repair near Vale Royal£198
Boiler repair near Amber Valley£204
Boiler repair near North Hertfordshire£224
Boiler repair near South Ayrshire£198
Boiler repair near Waverley£234
Boiler repair near Broadland£210
Boiler repair near Crewe & Nantwich£202
Boiler repair near Breckland£198
Boiler repair near Ipswich£240
Boiler repair near Pembrokeshire£176
Boiler repair near Vale of White Horse£216
Boiler repair near Salisbury£210
Boiler repair near Gedling£200
Boiler repair near Eastleigh£212
Boiler repair near Broxtowe£202
Boiler repair near Stratford-on-Avon£208
Boiler repair near South Bedfordshire£220
Boiler repair near Angus£208
Boiler repair near East Hampshire£214
Boiler repair near East Dunbartonshire£208
Boiler repair near Conway£192
Boiler repair near Sevenoaks£230
Boiler repair near Slough£236
Boiler repair near Bracknell Forest£238
Boiler repair near West Lancashire£204
Boiler repair near West Wiltshire£214
Boiler repair near Ashfield£200
Boiler repair near Lisburn£188
Boiler repair near Scarborough£192
Boiler repair near Stroud£204
Boiler repair near Wychavon£206
Boiler repair near Waveney£208
Boiler repair near Exeter£196
Boiler repair near Dover£216
Boiler repair near Test Valley£210
Boiler repair near Gloucester£234
Boiler repair near Erewash£202
Boiler repair near Cheltenham£208
Boiler repair near Bassetlaw£194
Boiler repair near Scottish Borders£212