Pilot light keeps going off—help?
If your boiler’s pilot light keeps going off, it’s often due to a faulty thermocouple, poor ventilation, or a dirty pilot jet. For example, if your flame turns yellow or orange, it may indicate incomplete combustion—shut the boiler off and call a gas-safe engineer immediately.
What Is a Boiler Pilot Light?
A pilot light is a small flame that ignites the gas in your boiler to generate heat. Common in older boilers, this tiny flame must remain constantly lit. If it keeps blowing out, it’s a sign that something’s not right.
Why Does the Pilot Light Keep Going Out?
When the pilot light goes out once, it may just be a small hiccup. But if it keeps happening, here’s what could be going wrong:
1. The Thermocouple Is Faulty or Misaligned
This safety device detects whether the pilot flame is burning. If it fails or gets out of position, it can mistakenly shut off the gas, even if the flame is still working.
Engineer’s Note: A misaligned or dirty thermocouple is one of the most common reasons for repeat blowouts.
2. Pilot Orifice Is Blocked
The pilot jet is a tiny nozzle that allows gas to flow. Dust or soot buildup can block the flow, causing the flame to become weak or unstable.
A weak flame won’t reach the thermocouple properly, leading to a shutdown.
3. Issues With Gas Supply or Regulator
If the gas supply is inconsistent, the pilot won’t stay lit. You might also notice other gas appliances (like hobs or fires) acting up—this points to a regulator issue.
Always report suspected regulator faults to your energy supplier.
4. Strong Draught or Poor Location
Wind can blow out the flame, especially if the boiler is located near external vents or open windows.
This is surprisingly common in older homes with poor insulation.
5. Carbon Monoxide Risk from Incomplete Combustion
A yellow or orange pilot flame indicates your boiler might not be burning gas efficiently—this can release dangerous carbon monoxide.
Warning signs of carbon monoxide:
- Yellow/orange pilot flame
- Headaches or dizziness indoors
- Condensation on nearby windows
- Pilot light frequently goes out
If you suspect this, switch off your boiler, ventilate your home, and call a gas-safe engineer immediately.
How to Relight the Pilot Light
Important: Never attempt to relight your boiler pilot light unless you’re certain it’s safe, and you’ve followed the manufacturer’s instructions.
For most homeowners, this is a job best left to the pros. Your boiler might be telling you there’s a more serious issue underneath.
A Gas-safe engineer can diagnose the cause safely and reset the system.
Can I Fix It Myself?
In short: No, not safely.
Boiler repairs involving gas should always be handled by qualified professionals. Attempting DIY could risk gas leaks or void your boiler warranty.
Prevention Tips: Keep Your Pilot Light Stable
Book an Annual Boiler Service
Your engineer will clean the pilot assembly, inspect the thermocouple, and test safety functions.
Install a Carbon Monoxide Detector
These are essential for any home with a gas appliance. Test it weekly, and place it near your boiler.
Ensure Proper Ventilation
Avoid blocking vents or sealing off rooms. Good airflow is key to safe combustion.
When to Call a Heating Engineer
If your pilot light:
- Goes out more than once
- Burns yellow/orange
- Accompanied by any physical symptoms (nausea, dizziness, headaches)
- Is a boiler over 10 years old
… it’s time to call a gas-safe engineer. They’ll inspect your system, test for gas flow and combustion safety, and provide professional fixes.
Time for a New Boiler?
If your boiler still uses a pilot light, it’s probably reaching the end of its life. Newer boilers are safer and more efficient and don’t rely on a constantly burning flame to operate.
At PlusHeat, we offer a range of boiler cover plans and installation services designed to keep your home warm and stress-free, without the guesswork.
