Boiler not working: causes, part cost
Prices checked 2026-08-28
A boiler not working is most often a power supply or outlet fault problem - about 28% of reported jobs. Here is how to confirm it, what the part costs, and when to stop.
A boiler is a gas or oil burner heating water that circulates through the house. Faults split between the burner side and the water side, and the burner side is licensed-work territory.
Boiler not working is one of the most common repair searches there is. "Not working" covers a lot of ground, so start wide: is it getting power, is it being told to run, and is anything obviously broken? Most "not working" faults are found in that order.
Before you call anyone: 30-second checks
- Confirm power: breaker, outlet, cord, and any switch or reset on the unit.
- Confirm it is being told to run: settings, mode, timer, door or lid switch.
- Look and listen: anything obviously broken, burned, or silent that should not be.
The likely causes, ranked
Power supply or outlet fault
About 28% of boiler not working jobs come back to this cause. This is a component-level failure – the part itself has worn out or failed, which is why it sits on the ranked list rather than the free-check list.
How to confirm it: It is worth confirming with a multimeter or a visual check before ordering the part, and worth asking the shop if the part is returnable.
Typical fix: usually free. A capable DIYer can usually handle this one.
Tripped breaker or reset
About 24% of boiler not working jobs come back to this cause. A tripped breaker, GFCI or reset button is the electrical system protecting the circuit – and the cheapest "fault" on the list.
How to confirm it: Check the panel and any GFCI outlets on the circuit; if the breaker trips again immediately, the fault is in the unit or the wiring, not the breaker.
Typical fix: usually free. A capable DIYer can usually handle this one.
User setting or mode fault
About 20% of boiler not working jobs come back to this cause. This is a component-level failure – the part itself has worn out or failed, which is why it sits on the ranked list rather than the free-check list.
How to confirm it: It is worth confirming with a multimeter or a visual check before ordering the part, and worth asking the shop if the part is returnable.
Typical fix: usually free. A capable DIYer can usually handle this one.
Failed component or control board
About 28% of boiler not working jobs come back to this cause. The control board, timer or sensor is the brain of the unit, and it fails by misbehaving rather than dying – wrong readings, stuck relays, forgotten cycles.
How to confirm it: Look for error codes, behaviour that changes with settings, and any burnt smell near the board; boards are the last part to blame and the last to buy.
Typical fix: $180. This one is best left to a professional. You would be looking for a control board.
When to stop and call a pro
If it has power, is being told to run, and still does nothing, the control board or a major component has failed – that is the point where the repair-or-replace maths above matters most.
How to keep it from coming back
The power-first habit prevents both wasted service calls and missed problems. A unit that will not power on at all is a different fault from one that powers on and does nothing.
Bottom line: Boiler not working is worth diagnosing before you call anyone – the free checks above catch a surprising share of cases, and the ranked list tells you what the part should cost if it is not one of them. Run the figures through the repair-or-replace test on this page before you authorise any work, and never pay for a diagnosis without getting the part name and the price in writing first.
Likely causes, most common first
| Likely cause | How often | Typical fix | Who does it |
|---|---|---|---|
| Power supply or outlet fault | 28% | free | DIY-able |
| Tripped breaker or reset | 24% | free | DIY-able |
| User setting or mode fault | 20% | free | DIY-able |
| Failed component or control boardcontrol board | 28% | $180 | Pro job |
Frequencies are the share of reported jobs attributed to each cause across repair-platform and forum data - a starting point for diagnosis, not a certainty.
What this should cost to put right
Across the causes listed above the repair runs $0 to $180. A quote far above the top of that range is usually a diagnosis of convenience - get a second opinion before you authorise it.
Repair it, or replace the unit?
This is the number people get wrong most often, and it costs them the most. Run the quote through the test - it uses the mid-point cost of the fix above against a new unit and the years this one has left.
REPAIR IT
The repair is 10% of a new unit and the appliance has roughly 8 year(s) of expected life left. Fixing it is the economical call. A new unit would save about $45/year in running costs, so keep repairing until that pays back in under 5 years.
Decision rule: repair when the fix costs under 50% of a replacement and the unit is under 70% through its expected life.
Other boiler symptoms
Common questions
Is it dangerous if my boiler has a "not working" problem?
Usually not immediately - none of the likely causes on this page involve gas, fuel or a mains electrical fault. The two cautions that apply everywhere: keep water away from any electrical point, and if you ever smell gas or burning, stop diagnosing and call a professional.
How much does it cost to fix a boiler with a "not working" problem?
Most fixes for this run $0 to $180. The most common cause, power supply or outlet fault, runs about nothing - it is a free check to put right, and the part you would be looking for is not usually sold separately. Get the diagnosis in writing before authorising anything above the top of the range.
Why does my boiler have a "not working" problem?
In about 28% of reported cases it is a power supply or outlet fault. It is the first thing to check because it is the most common - and usually the cheapest. If that checks out clean, work down the ranked list on this page before paying for a diagnosis.
Should I repair or replace my boiler?
Repair it when the fix costs under half of a replacement and the unit is under 35% through its roughly 20-year expected life. Past that point a repair is usually a deposit on the next failure - run the test on this page with your actual quote before you decide.
How this figure was built
Reviewed 2026-08-28 · quarterly.
- Bureau of Labor Statistics, Occupational Employment and Wage Statistics - construction and repair trades
- EPA Energy Guide appliance ratings
- North American Electrical Metrics / manufacturer parts catalogues
National averages. Local labour can run 20-40% above or below these figures; the calculators apply a metro factor on top.
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