Why does my furnace not ignite sometimes?

If your furnace won’t ignite, the source of the issue may be a broken flame sensor. The sensor is responsible for turning off the gas burners to avoid gas buildup. Once this component starts to malfunction, it may stop the burners from igniting altogether.

How do I know if my furnace ignitor is bad?

If you have a faulty furnace ignitor, it won’t produce that tiny spark to heat the air coming from your Furnace. Your heater blows air at the same temperature as the cold outside air without it. Cold air blowing through your vents is a good sign that you have a heating problem within the Furnace.

How do you test a spark ignition furnace?

Quote from the video:
Quote from Youtube video: So we're going to turn the power on our multimeter exceptive volts AC.

What is intermittent ignition?

Intermittent Pilot Ignition is an electronic system, which uses an electrode to ignite the pilot gas. In turn, the pilot flame lights the main burner gas. The term Intermittent is used because the pilot burner flame is only present when the main burner is operating.

How do I clean my furnace ignitor sensor?

Quote from the video:
Quote from Youtube video: So if you have a situation like this what you have 90% of the time is just a dirty flame sensor. So we'll go through the steps on how to clean it. So the right side of the furnace.

How do you clean a furnace sensor?

Clean the Sensor

Once you have removed the sensor, gently rub the metal rod (and nothing else) with a very light grit sandpaper. Remember, you’re not sanding down an auto body here, just ridding the sensor of any buildup. Then, use a clean paper towel to wipe clean any dust left behind by the sanding.

How do you test an igniter with a multimeter?

Test The Ignitor With A Multimeter

Set a multimeter to the lowest possible resistance test and place the probes onto tips of the plug for the ignitor. If the multimeter shows infinity or stays at zero, the ignitor no longer works and must be replaced.

How do you test a furnace hot surface ignitor?

Quote from the video:
Quote from Youtube video: The element here gets red-hot and begins to glow. At the same time the gas valve is energized allowing gas to flow across the hot surface igniter this ignites the gas to test the igniter.

What does it mean when a furnace is short cycling?

What Is Furnace Short-Cycling? A furnace short-cycles when its heating cycles turn on and off but does not allow the room to reach the set temperature. Short cycles will also happen more frequently than cycles of normal duration.

How do you reset the electronic ignition on a furnace?

To reset the ignition control module on an electronic-ignition furnace, turn down the thermostat or turn off the power switch. Listen for the sound of the spark or watch for the hot surface ignitor to glow. Next, make sure the furnace’s flame sensor is clean.

Can you manually light a gas furnace with electronic ignition?

If your furnace is equipped with an electronic igniter, you cannot light the furnace manually. However, you may be able to get the furnace working by turning off the igniter and resetting it. Find the paperwork for your particular furnace to locate the reset button or switch.

What is the difference between direct spark ignition and intermittent spark ignition?

First off lets handle direct spark ignition. There is NO pilot light on this systeml. The spark ignition is directed to the main burner. Now there is a condition known as “intermittant sparking” that refers to the spark continueing to fire after the furnace (or stove) is lit.

How do I check my direct spark ignitor?

Quote from the video:
Quote from Youtube video: If the igniter has continuity your multimeter should read anywhere from ohms if there is no reading on the multimeter. Or very little change then there is no continuity.

How do you troubleshoot a spark ignition?

Quote from the video:
Quote from Youtube video: This right here is actually the flame sensor the flame sensors job is only not since the plane but to actually put anywhere should say 90 to 130 volts into the flame. And then it's going to rectify.

When a furnace goes into a hard lockout?

A hard lockout happens after several repeated soft lockouts. For most furnaces, you will have three attempts to relight the unit before it goes into hard lockout. If this happens, you will have to reset the unit manually. The best way to do this is by calling your go-to HVAC technicians to perform the reset sequence.

How many times can I hit the reset button on my furnace?

Don’t hit “reset” more than twice. The process pumps oil into the burner chamber, where it can accumulate if you have no ignition. Then when the furnace finally does start, it can do so explosively. So if the button won’t reset, or quickly pops up again, it’s time to call a professional repair service.

What causes a pressure switch cycle lockout?

If your furnace isn’t venting correctly, the pressure switch may be stuck open. This is often caused by a blocked flue pipe, which makes it hard for the system to eliminate combustion gases. The flue pipe can easily get trapped with leaves, feathers, dirt, and other debris.

How do I know if my furnace pressure switch is bad?

Quote from the video:
Quote from Youtube video: So if you're testing a pressure switch that closes at negative point seven inches water column. Then the suction being read by the meter should be around. Say negative one inch water column.

How do you test a furnace pressure switch?

Disconnect the wires connected to the pressure switch by pulling the wire connectors off of the switch terminals. Set a multimeter to test for resistance (ohms). Touch each tester probe to one of the switch terminals. The tester should read 0 or close to 0 (indicating no resistance).