A gas furnace uses fire to produce heat. If there is not a flame, your unit will be unable to heat up, and thus, your home won't be warm. If you notice that the flame has gone out, you will want to reignite it. A gas furnace pilot light that goes out every once in a while is nothing to worry about. However, if you find that the flame continues to go out, you have a bigger issue that needs to be addressed. Here are a few reasons why your flame keeps going out and how you can work to fix it.
A Dirty Flame Rod
A flame rod, also called a flame sensor, may be just a small stainless steel rod, but it plays an important role in your furnace. The rod carries a small electrical charge when a flame is present. This electrical charge keeps the gas line open, which allows gas to flow and the fire to remain going. When there is no fire present, the rod does not carry this electrical charge, which causes the gas line to turn off. Unfortunately, if the rod becomes dirty, it may not be able to supply the electrical charge it needs in order to keep the gas line open. As such, a flame may ignite initially, but gas won't continue to flow. Cleaning the flame rod can help to remedy this problem. Follow these steps to clean your flame rod or flame sensor:
- Allow your furnace to cool completely before opening it and touching anything inside. The parts can be hot and will burn you if you do not allow them to cool.
- Locate the flame rod in your gas furnace. Open the furnace door and locate the three circles near the top of the unit where you should see fire. If you cannot determine where this is, press your igniter switch and see where the fire sparks from. The flame rod will either be to the left or right of the middle circle. It usually has a white knob on it with a piece of wire coming out of it.
- Turn your furnace off. Gently pull the wire out of the flame rod. Some flame sensors have a screw holding them in place. If you notice a screw when you remove the wire, use a screw driver to remove the screw. Pull the white cap outward to remove the flame rod.
- Lightly rub the stainless steel rod with a stainless steel scrubbing pad or fine-grit sandpaper. Do not use soapy water as this can cause the steel to rust. Continue rubbing until all build up is removed.
- Reinsert the rod and attach the wire. Turn your furnace back on and ignite the flame. If this was the problem, your flame should now stay lit.
The Thermocouple is Going Bad
A thermocouple is a small steel tube with a copper wire in it. This item is located near the pilot light burner. The copper can sense when the pilot light burner is on and when it is off. Should the pilot light turn off, the thermocouple is responsible for sending a signal that shuts the gas off so you don't have a gas leak. However, if this safety device is going bad, it may signal to turn the gas off when it shouldn't, which in turn can cause your flame to go out. Follow these steps to replace your thermocouple:
- Turn your gas furnace off and allow it to completely cool.
- Open up your furnace and locate your pilot light. This is in the same vicinity as your flame rod. However, it will either be completely to the left or right side of the furnace. If you are unsure where the pilot light is, turn your furnace back on and ignite it. Look for where the first spark comes from as your furnace ignites, as this is the pilot light Turn your unit back off.
- Right beside the pilot light you will notice a steel tube. This tube houses the thermocouple. Gently tug on the bottom portion of the thermocouple, known as the copper lead, to remove it. Use a wrench and locate the connection nut that is on the underside of the bracket holding the thermocouple in place. Unscrew this nut to remove the stainless steel portion of the thermocouple
- Insert your new thermocouple into the bracket. The steel half should be pointing upward and the copper side should be downward. Push your connection nut back into place and tighten it.
- Turn your furnace back on and ignite the flame. If the flame stays lit, you have solved the problem.
A dirty flame sensor rod and a faulty thermocouple are two of the reasons why your furnace may not stay lit. Unfortunately, they are not the only reasons. You may have a gas line blockage, a faulty pressure switch or your unit is shutting down because it detects a gas leak. If the above methods don't solve your problem, a professional furnace repair company can diagnose your furnace and complete these more challenging repairs, helping you to get your furnace working again.
For more information, contact a company like Custom Comfort.