How to Fix a Gas Fire That Keeps Going Out
There are two gas fires in our house: one in the living room, the other in the kitchen. The latter kept going out after about half an hour, even when the dial showed it as on. Though I don't worry too much about carbon monoxide poisoning, I figured there must be some safety device to shut off the gas valve.
After doing some research, however, I now have basic knowledge about gas fires and have successfully fixed my gas fire. All it took was for me to blow through a drinking straw over the pilot/thermocouple area to clean them out. (This saved us at least £30.)
Different makes and models have different safety devices, however. Some have only a thermocouple, and some have an oxypilot (an atmospheric vitiation sensing device). So it's best to do some research on your particular make and model before attempting any repairs.
You can learn more about these devices below, including how they work and how you might be able to fix yours so that your gas fire won't keep going out.
How the Pilot Works in Your Fire
- When you first start the fire, keep it on the pilot light for a couple of seconds, and the fire should "kick on" when you turn the dial from the pilot light to the on position. (Sometimes you need to hold the pilot light on for longer to ignite the main fire.)
- When the pilot is lit, there should be two flames: one over the burner and the other (smaller one) touching the thermocouple.
- If you get dust in the pilot assembly and the pilot needs to be cleaned out, it produces a "lazy" flame, which will be disturbed by the draught of the main burners. The flame lifts away from the thermocouple and causes the temperature on the tip of the thermocouple to drop. This, in turn, makes the gas valve shut off.
- The fire produced by the pilot should be sky blue in the middle and dark blue in the outer flame, rather than a flame tinged with yellow. It should be directed at heating the tip of the thermocouple.
How the Thermocouple Works
A thermocouple is a type of thermometer that consists of two wires of different metals that are joined at both ends. One junction is at the temperature to be measured, while the other is held at a fixed lower temperature.
The current generated in the circuit is proportional to the temperature difference. The thermocouple works by this difference. Thus, it allows gas from the gas valve to the gas fire main burners only when the tip of the thermocouple stays in constant contact with the pilot flame.
How the Oxypilot Works
An oxypilot is an atmospheric sensing device in place to put out the gas fire if there is insufficient oxygen in the room. It is designed as a safety device to protect you from carbon monoxide poisoning if the air in a room becomes vitiated.
Basically, if the oxygen percentage in a room drops, the flame shape is altered by its incomplete combustion. The heat is then removed from the thermocouple, shutting off the gas valve. If the oxypilot becomes blocked with dust or soot, the flame lifts away from the thermocouple or flame sensing electrode. This will make the fire cut out, or pilot not light.
How to Fix a Faulty Gas Fire
- Between the pilot supply pipe and the pilot burner, there's a brass tail or connector. There'll be a small hole on one side. Make sure there's no dust blocking this, and clean if needed.
- Then, place a bit of tubing or a drinking straw over each pilot hole. Blow down through the straw to clean it out.
Get Your Gas Appliances Serviced Every Year
For optimal efficiency and safety, gas appliances should be serviced every 12 months.
Hire a CORGI-Registered Gas Installer
Even if you have solid knowledge of gas fires, you still need a CORGI-registered gas installer to work on gas appliances when you have to break or disconnect any gas supplies or fittings or try to change parts.
Hiring a CORGI engineer to service the fire involves removing the gas fire and checking the chimney with a smoke pellet. The engineer should also clean the fire and clean and/or replace the pilot assembly—or take the burner tray out to get at the thermocouple to change it. This may cost you around £30–£50 or more.
This article is accurate and true to the best of the author’s knowledge. Content is for informational or entertainment purposes only and does not substitute for personal counsel or professional advice in business, financial, legal, or technical matters.
© 2009 Dalriada Books Ltd