Can I run a furnace without a flame sensor?

If the pilot flame goes out, the flame sensor will turn the unit off to prevent natural gas from leaking into the home. Without the flame sensor, if the pilot light goes out but the gas valve remains open, the gas will not burn and will seep out of the furnace.

What does flame sensor do on furnace?





A flame sensor is a crucial safety component on your gas heating system. During the ignition cycle, your gas furnace goes through a process where a spark or a hot surface ignitor will actually ignite the gas. As the gas is ignited, the flame sensor creates a current of electricity.

How do I know if my furnace flame sensor is bad?

6 Signs of a Malfunctioning Gas Furnace Flame Sensor

  1. Yellow Burner Flames. Open up or glance through the peephole of your gas furnace to see the color of the flames firing up in the burner. …
  2. Rusted Flue Lines. …
  3. High Utility Bills. …
  4. Water Leaks. …
  5. Old Age. …
  6. Constant Thermostat Adjustments.


What would cause a furnace not to kick on?

Ensure your furnace filters are clean: Your furnace won’t start up if it does not get enough airflow. A dirty air filter can prevent airflow and prevent your furnace from starting up. Check your pilot light: If you have a gas furnace and gas supply is stopped your pilot light will go out.

How do you trick a flame sensor?





Luckily, making such a check is very easy:

  1. Take a multimeter with microamps (µA) measuring system.
  2. Keep the furnace system turned on.
  3. Connect it to the wire that is leading to the gas valve.
  4. Connect the other side of the multimeter to the sensor terminal.
  5. Take the lead away from the flame sensor.

Why do flame sensors fail?

Possible Causes of a Flame Sensor Malfunction



The most common is that it is dirty. Because burning fuel of any kind produces trace amounts of moisture, over prolonged exposure to these conditions, metal will rust. Since your sensor is made of metal, rust can build up, preventing proper sensing of the flame.

How do you reset the flame sensor on a furnace?

Quote from the video:
Quote from Youtube video: And we're just going to sand this a little bit and we'll see if that solves our problem all right I used our Emery cloth and I remove the buildup from the flame on the thermocouple.

When should I replace my flame sensor?

If you’ve just replaced the sensor or had a new furnace installed, you can expect the flame sensor to last for about five years. The average lifespan of a furnace is 15 to 30 years, so you can anticipate a flame sensor replacement once or twice over the course of your homeownership.

Is the flame sensor the same as the igniter?



The flame sensor is able to detect the heat caused by combustion. When it does, it sends the signal to stop powering the hot surface igniter. If, on the other hand, a certain period of time elapses in which the flame sensor cannot detect a flame, it will automatically shut off the gas valve.

Why is my furnace running but no heat?

Dirty filters are the most common cause of furnace problems. Dust and dirt restrict airflow—and if the filter gets too clogged, the heat exchanger will overheat and shut off too quickly, and your house won’t warm up. If the blower is running but no heat is coming out, replace the filter.

Why is my furnace blowing cold air when the heat is on?

If your furnace is blowing cold air in your home, this is a sign of an issue with the flame detector, gas supply, air filter, pilot light, or condensate lines. Many of these issues are able to be easily solved on your own by sanitizing or replacing components in the gas furnace.

Why is cold air coming out when the heat is on?



This issue could be caused by an improper thermostat setting. Check that the fan blower switch is set to “auto” and not “on.” When the “auto” setting is chosen, the fan will only run during a heating cycle and won’t push air that feels cooler through the vents in between cycles.

Why is my heating system blowing cold air?

A clogged filter is one of the leading reasons for a heater blowing cold air. But even if you swap the air filter with a brand new one, dirt and debris can still be found within the unit. This could eventually lead to overheating. If your furnace looks pretty dirty, call an HVAC provider for a professional clean.

Why is cold air coming out of my vents when the heat is on in my car?

Low Coolant Level



The coolant (usually a mixture of water and antifreeze) in your engine doesn’t just work to keep the engine from overheating: It’s also the source of heat supporting the heating system. If there isn’t enough coolant in your system, the heater core will blow cold air into your car.

Why does my furnace turn off after a few minutes?

A common reason a furnace short cycles is because the heat exchanger, the part that heats your air, is getting too hot due to a lack of airflow. Once the heat exchanger overheats, it trips the high limit switch, which shuts the furnace down to protect it.

Why does my furnace keep shutting off after a few seconds?



So, if your furnace keeps turning off and on too quickly, your thermostat might be malfunctioning or broken. There are several things that could be causing your thermostat to not work properly. The wiring could be old and need replacing, it might need new batteries, or it could be the location of your thermostat.

Why does my furnace turn on and off every 5 minutes?

A full heating cycle for a furnace or heat pump is usually around 15 minutes or more. If your heater keeps turning off after only five minutes, that’s too short—no matter how low you’ve set the thermostat.