The Pilot Light Keeps Going Out On My Gas Furnace
November 03, 2017
If your gas furnace’s pilot light keeps going out, you’re probably frustrated (and cold).
So what’s the problem?
Well, if your gas furnace pilot light won’t stay lit, it’s usually due to 1 of these 4 issues:
- A bad thermocouple
- Pilot light problems
- Bad gas regulator
- Bad gas valve
We know—those “issues” are pretty vague. Don’t worry, we’ll explain them in detail and show you what you can do to get your heat back.
Need a professional furnace repair ASAP? Just contact us and we’ll send a tech right over.
Problem #1: A bad thermocouple
Your furnace’s thermocouple is a copper rod that sits next to your furnace burners. It’s often called the “flame sensor” because its job is to detect whether the pilot light is lit or not. If it can’t sense a flame from the pilot light, it prevents the gas valve from opening and sending more gas into the combustion chamber.
So your thermocouple is basically a safety feature that prevents a dangerous buildup of gas in your home.
But if your thermocouple is broken, dirty or not lined up properly, it might not sense a pilot light’s flame (even when it’s lit). And when this happens, your thermocouple will shut off all gas flow to your furnace—meaning your pilot light will go out for good (and you won’t even be able to manually light it).
What to do:
Problem #2: Pilot light problems
If your pilot light:
- Stays lit for a few seconds but goes out
- Has a weak, yellow flame (instead of blue)
...then you most likely have a dirty or restricted pilot light orifice.
You see, the pilot light orifice controls the flow of gas to your pilot light. The pilot light needs a strong flow of gas to make a strong, steady blue flame that the thermocouple can sense. But if the orifice is dirty or restricted, the pilot light won’t light properly. Which means the thermocouple will shut off the gas flow to your furnace as a safety measure.
What to do:
Because accessing the orifice requires removing your furnace’s burner assembly, we suggest having a professional clean the pilot orifice.
Problem #3: A bad gas regulator
Your gas regulator is usually located at your home’s gas meter. Its job is to decrease the pressure of the natural gas before it enters your home and gas appliances. But if the regulator is old or broken, it may not allow gas to flow at a strong or steady enough pressure to light your furnace’s pilot light.
You’ll know that a bad gas regulator is your problem if you notice pilot problems in other gas appliances in your home (such as your gas water heater or gas stove).
What to do:
Have a professional check your gas regulator for problems. They’ll replace the regulator if it’s gone bad.
Problem #4: Bad gas valve
Your furnace’s gas valve delivers gas to your pilot light and combustion chamber. Without that gas, your pilot light couldn’t light. So if the valve is accidentally turned to the OFF position or has gone bad, your pilot light won’t stay lit.
What to do:
A gas valve typically can’t be repaired once it’s gone bad. You’ll need to have a licensed professional inspect the valve and replace it if it has become faulty.
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