Why Your Boiler Fires Up Then Shuts Off in Liphook
Nothing’s more unsettling than seeing your boiler ignite, only to have the flame vanish moments later. If you live in Liphook (GU30) or nearby areas like Bordon, Haslemere and Farnham, you might be facing a common issue known as a flame sensing fault. During colder months, these faults can leave your radiators cold and your household without heating or hot water when you need it most.
In this guide, we’ll explain how flame sensing works, what typically goes wrong in local homes, and walk you through practical troubleshooting steps. We’ll also cover when it’s best to call a Gas Safe engineer and how regular maintenance can keep your boiler running smoothly.
How Does Flame Sensing Work?
Modern boilers rely on a tiny sensor—often a thermocouple or flame detection electrode—placed close to the burner flame. When the gas ignites, the heat produces a millivolt signal or open flame current that the boiler’s control board recognises as proof of combustion. If the signal falls below a set threshold, the boiler’s safety system assumes the burner isn’t lit and shuts off the gas supply to prevent dangerous gas build-up.
This safety feature is essential, but it also means that any disruption to the sensing circuit can trigger an automatic shutdown, even if the flame appears to ignite normally.
Common Causes of Flame Sensing Faults
- Dirty or Corroded Sensor Electrode: Over time, soot and debris build up on the electrode tip, impairing its ability to detect the flame.
- Worn Thermocouple: Thermocouples lose efficiency with age, producing a weaker voltage and failing to signal a steady flame.
- Gas Pressure Issues: Low or inconsistent gas pressure can cause the flame to sputter or blow out, preventing a stable reading.
- Air in the Gas Line: During gas meter replacements or maintenance, air can enter the supply, causing temporary ignition faults.
- Loose Connections: Vibrations or poor servicing can leave sensor wiring muffled or disconnected, interrupting the signal to the control board.
Signs You Might Have a Flame Sensing Problem
Aside from the boiler firing up then shutting off, you may notice:
- Multiple reset attempts are required before the boiler stays on
- Unusual burner noise, such as hissing or clicking
- Cold spots on radiators or inconsistent heating
- Error codes on the boiler display indicating ‘flame loss’ or ‘fault 112’ (model dependent)
Troubleshooting Steps for Liphook Homeowners
Before you pick up the phone, try these safe, do-it-yourself checks:
- Reset Safely: Most boilers have a reset button—hold it for the recommended time, usually five seconds, and wait three minutes between resets to allow the system to clear.
- Check System Pressure: Low water pressure can cause the boiler to shut down. Ensure the gauge reads between 1 and 1.5 bar.
- Clean the Sensor: Switch off power and gas, remove the boiler cover, and gently clean the flame sensor tip with fine emery paper. Avoid bending or damaging the wiring.
- Examine Ventilation: Verify that air vents around the boiler are clear—good airflow prevents overheating and pressure drops at the burner.
- Inspect the Gas Supply: Confirm your meter hasn’t tripped, and other appliances like your stove or gas fire work properly.
- Review the Manual: If your boiler shows an error code, check the homeowner’s guide for troubleshooting advice.
When to Call a Gas Safe Engineer
If the boiler still won’t stay lit after basic checks, it’s time to call in a professional. In areas like Liphook, Petersfield and Farnham, our certified Gas Safe engineers are equipped to:
- Test and adjust gas pressure at the injector
- Replace aged thermocouples or electrodes
- Repair or reseat wiring and connectors
- Perform a full safety check on flues and ventilation
Attempting complex internal repairs yourself can lead to gas leaks or damage to the control electronics. A qualified engineer not only restores your heating quickly but ensures compliance with safety regulations.
Preventative Maintenance to Avoid Interruptions
Annual servicing is the most effective way to stop flame sensing faults before they start. Booking regular boiler servicing will include:
- Cleaning burners and flame sensors to maintain reliable ignition
- Checking for corrosion and replacing worn parts
- Testing system pressure and topping up if necessary
- Power flushing radiators to eliminate sludge that can cause cold spots
Well-maintained boilers run more efficiently, saving you money on energy bills and extending the life of your appliance.
Considering a New Boiler Installation?
If your existing boiler is over 10 years old or repair costs are rising, a new boiler installation might be more cost-effective. Today’s condensing boilers offer superior flame detection systems, better fuel efficiency and low noise levels—ideal upgrades for homes throughout GU30 and GU35 postcodes.
Protect Your Investment with Boiler Cover
No one likes unexpected repair bills. Signing up for a comprehensive boiler cover plan safeguards you against common faults, including sensor failures and ignition problems. Whether you’re in Haslemere, Whitehill or Liss, having cover means prompt repairs and peace of mind.
Frequently Asked Questions
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Q: Why does my boiler light then immediately go out?
A: This is typically a flame sensing fault. The sensor may be dirty, misaligned or worn, triggering an automatic shutdown to prevent gas leaks.
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Q: Can I fix a flame sensing fault myself?
A: You can safely reset the boiler and clean the flame sensor, but any gas line or wiring work must be done by a Gas Safe registered engineer.
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Q: How often should I service my boiler?
A: Annual servicing is recommended to ensure reliable ignition, efficient performance, and to catch small issues before they become major faults.
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Q: How do I know if I need a new boiler?
A: Frequent shutdowns, rising repair costs, and an appliance older than 10 years are good indicators that a new high-efficiency boiler could be the better long-term choice.
If you need help with your heating or boiler, our local engineers are here to help. Call us on (01420) 558993 or book online at embassygas.com/book
Written by Embassy Gas — your local heating experts covering Liphook, Bordon, Farnham and surrounding areas.