A boiler that suddenly stops working is more than just an inconvenience—it’s a problem you want fixed fast, especially in winter.
This guide covers:
- Common causes
- What to check first
- How to restart a boiler
- When to call an engineer
Let’s break it down.
1. First Things First: Is It a Total Power Issue?
Start simple. If your boiler has no lights or display, check:
- Power supply: Has a fuse tripped?
- Switched socket: Is the plug on and working?
- Other appliances: If they’re off too, it’s likely a wider power cut.
2. Common Reasons a Boiler Stops Working
Here are the most frequent culprits:
- Low pressure: Should be around 1–1.5 bar. Too low, and the boiler won’t ignite.
- Frozen condensate pipe: Common in winter. Look for an external plastic pipe that’s icy.
- No gas supply: Check your gas appliances or contact your supplier.
- Faulty thermostat: Could be broken or set too low.
- Pilot light out: If it’s a gas boiler with a pilot, this could be the issue.
- System lockout: Error codes or flashing lights usually mean the boiler has shut down to prevent damage.
3. What to Try Before Calling a Heating Engineer
Check boiler pressure:
If it’s low, you may be able to repressurise it using the filling loop (check your manual).
Reset your boiler:
Use the reset button (usually on the front panel). Don’t do this repeatedly—once or twice is fine.
Bleed your radiators:
If only the heating isn’t working properly, trapped air could be to blame.
Check thermostat and timer settings:
Sometimes they’re accidentally changed or lose sync after a power cut.
4. When It’s Time to Call a Professional
Don’t mess with gas components or electrical internals. Call an engineer if:
- You smell gas
- The boiler shows recurring error codes
- You’ve tried the basics and nothing works
- There’s leaking water or visible damage
- There’s no heating or hot water for over 24 hours
5. Heatforce Boiler Services
If your boiler stops working, we offer:
- Emergency repairs
- Full boiler diagnostics
- System flushes
- Boiler replacements
We install and repair all major boiler brands, including Worcester Bosch, Ideal, and Vaillant.
6. How to Prevent Boiler Breakdowns
- Book annual servicing
- Bleed radiators regularly
- Keep pipes insulated in winter
- Install a magnetic filter to catch sludge
- Use your heating occasionally in summer to keep parts moving
7. Need a New Boiler?
If your boiler is:
- Over 10–15 years old
- Breaking down often
- Out of warranty
- Struggling to heat your home efficiently
…it may be more cost-effective to replace it.
We offer free quotes, finance options, and fast installation by Gas Safe engineers.
FAQs – When Boiler Stops Working
Why has my boiler suddenly stopped working?
Most likely causes include low pressure, power supply issues, frozen condensate pipe, or a lockout due to a system fault.
What should I check first if my boiler isn’t working?
Start by checking the power, pressure gauge, thermostat settings, and whether there’s a visible error code.
Can I reset my boiler myself?
Yes, most boilers have a reset button. Press and hold it for a few seconds. If the issue persists, call a professional.
How do I know if it’s a frozen condensate pipe?
You may hear gurgling, or see a visible error code. If it’s below freezing and your condensate pipe is external, that’s likely the cause.
Should I try to repressurise the boiler?
You can if you’re confident and follow your boiler’s manual. If unsure, it’s safer to call a heating engineer.
How long does it take to fix a boiler?
Minor issues can be resolved in under an hour. More serious faults may take longer or require parts.
Is it dangerous if my boiler stops working?
Not always, but it can be if there’s a gas leak, electrical issue, or pressure problem. Turn off the system and call for help if in doubt.
Does boiler insurance cover breakdowns?
Depends on your plan. Many home cover plans include emergency boiler repairs.
Can a faulty thermostat cause a boiler to stop working?
Yes. If the thermostat fails or loses calibration, it might prevent the boiler from firing up.
When should I replace my boiler instead of repairing it?
If repairs are frequent, expensive, or the boiler is over 10 years old, a replacement might be the better option.
