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Boiler Breakdown

No heating or hot water? Learn what to check first, common causes of boiler breakdowns, repair costs and how to find a Gas Safe registered emergency heating engineer.

Last reviewed: August 2026 · Reviewed by: The TopTenTrades Editorial Team

Quick Answer

  1. 1.Check the boiler pressure gauge and any error codes
  2. 2.Check you have not run out of gas or prepayment credit
  3. 3.If you smell gas, leave the property and call 0800 111 999
  4. 4.Try resetting the boiler following the manufacturer instructions
  5. 5.Contact a Gas Safe registered emergency engineer
Problem type
Emergency heating
Typical trade
Gas Safe registered heating engineer
Urgency
Immediate, especially in winter
Typical repair time
1–2 hours
Typical cost
£80–£400
Risk if ignored
No heating or hot water, frozen pipes, higher repair costs

What To Do

  1. 1.Check the pressure gauge — most boilers need pressure between 1 and 1.5 bar when the heating is off.
  2. 2.Look for an error code on the boiler display and note it down for the engineer.
  3. 3.Confirm you have gas supply and, on a prepayment meter, that you have credit.
  4. 4.Try a manufacturer-recommended reset — do not attempt to open or repair the boiler yourself.
  5. 5.If you smell gas at any point, leave the property immediately, do not use electrical switches, and call the National Gas Emergency Service on 0800 111 999.
  6. 6.Contact a Gas Safe registered engineer for an emergency callout.

Signs You May Have This Problem

  • No heating or hot water
  • Boiler pressure reading is low or has dropped suddenly
  • Unusual banging, whistling or gurgling noises
  • The pilot light keeps going out
  • An error code showing on the boiler display
  • A smell of gas near the boiler

Common Causes

  • Low system pressure
  • A faulty thermostat or timer
  • Airlocks or a broken diaphragm
  • Ignition or pilot light failure
  • A frozen condensate pipe in cold weather
  • General wear from an ageing boiler

Boiler Breakdown: Typical Costs

RepairTypical Cost (UK)
Emergency callout£80–£150
Minor repair (e.g. reset, reignition)£100–£200
Part replacement (e.g. pump, valve)£150–£400
Full boiler replacement£1,500–£3,500+

Costs depend on the fault, parts required, boiler make and model, and whether the callout is during standard hours or out of hours.

When Should You Call An Emergency Professional?

  • check_circleYou can smell gas
  • check_circleThe boiler is showing a lockout or fault error code
  • check_circleResetting the boiler has not resolved the issue
  • check_circleThere is no heating or hot water in cold weather
  • check_circleYou notice black marks (soot) around the boiler

How To Prevent This

  • Book an annual boiler service, ideally before winter
  • Bleed radiators regularly to maintain even heating
  • Insulate the condensate pipe to reduce the risk of freezing
  • Keep the boiler pressure topped up to the manufacturer's recommended level
  • Address small faults early rather than waiting for a full breakdown

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  • Qualifications
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Need help with a boiler breakdown?

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