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Video:How to Fix a Gas Furnace: Produces No Heat

with Erick Noack

The function of a gas furnace is to produce heat; if yours is not producing heat, it needs to be fixed. Here's a video with instructions on how to fix a gas furnace that produces no heat.See Transcript

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Transcript:How to Fix a Gas Furnace: Produces No Heat

Hi, my name is Erick Noack. I'm an HVAC technician for ABC Plumbing, Heating, Cooling, and Electric. And we're here for About.com. Today we're going to talk about some things that you can check when your gas furnace stops producing heat.

Make Sure Thermostat is Adjusted Properly

Some possible causes of that are: thermostat not adjusted properly, the power going to the furnace could be shut off, the gas going to the furnace could be shut off, or the pilot light could be out. A couple things to check with the thermostat: Now, the first thing to remember is that everybody's thermostat is going to be different. In this case, when the red light is on, that means that it's in heat mode, so it's ready to heat the house. The next thing to check is to make sure the set point is higher than the room temperature. So if we raise that set point above the room temperature, that's going to turn the heat on.

Make Sure Gas Furnace is Getting Power and Gas

Another possibility is lost power to the furnace. You would check in your breaker panel, and make sure that the circuit to the furnace is active. When you go to check power to the furnace, you open up your panel cover, you want to look at the listing and find the circuit that is corresponding to the furnace. And then check that number on the breaker itself and make sure that the lever is in the correct position. Another potential is if the gas valve is shut off to the furnace, that would stop it from operating as well. So this is your gas shut off valve. When the lever is parallel with the pipe, that means that the gas is turned on. If it were turned perpendicular, that means that the gas is shut off, and the furnace cannot operate.

Some Gas Furnaces Have Pilot Lights

Another possibility is that your pilot light has gone out. Now, this is a pretty unusual occurrence, because most furnaces don't use pilot lights anymore. If your furnace does use a pilot light, then that would be the next thing that you'd want to check. The important thing to remember when you're checking your pilot light is read the manufacturer's instructions. It's very important, we're dealing with gas here. You need to follow these instructions very carefully. Most modern furnaces don't have a pilot light, so we're going to demonstrate how to light the pilot on this water heater. In this case, the first thing that needs to happen is that the thermostat needs to be turned all the way down to where it says pilot lighting. Next thing is to turn the valve to face pilot. That sets it up to where the pilot can be lit.

Re-Lighting a Pilot Light in a Gas Furnace

The next thing you need to do is identify where the pilot is, and that's by following the tubes down into the burner. You're going to need a BBQ lighter or a long wooden match to reach inside where the pilot is. Once you have that pilot identified and light your lighter, then you want to go into there and be ready right at the pilot before you push this button down. When you push this button down, it sends gas to the pilot valve, and it will ignite once you introduce the flame. At that point, you need to hold that button down for about a minute and then release it. If the flame holds, it means the system is working. If the flame doesn't hold, you can try again and hold it longer, or you may need to have service.

Knowing a little bit about your system and being educated about it is the best way to stay on top of it and avoid breakdowns. Thanks for watching. To learn more, visit us on the web at About.com.

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