Grab a multimeter to check the voltage going to the ignitor connection. Gently put the probes of the meter inside the plug. Make sure you only touch the tips of the plug and not damage it by pushing the probes through. If the value on the meter reads anything above or below 120 volts, the ignitor is bad.
In order to verify that ignitor is actually bad, it would be best to check voltage to the ignitor on a call for heat. This can be done by getting a voltmeter, setting it to ``volts AC'' and checking voltage across ignitor leads right about the time ignitor would normally glow.
Defective Igniter or Pilot Light
If it clicks but your furnace won't ignite after the combustion cycle, the electronic ignition systems probably need to be replaced. In cases where the furnace ignition starts normally but only stays on for a few minutes and then goes out, a new pilot light likely needs to be installed.
You can reset the ignition on your furnace simply. To do this you must cut the power to the furnace first by turning off the circuit that powers it. Once the power is off you can remove the burner door to reveal the ignitor. Turn this to “off” and leave it off for at least 5 minutes.
Here are some of the most common reasons why the ignitor fails. Using The Wrong Ignitor: Ignition failure will happen if your furnace uses an ignitor that has the incorrect voltage. The Limit Switch Becomes Too Hot: Furnaces have a built-in limit switch that detects high temperatures and prevents overheating.
Typically, you'll find it inside the air handler, either next to or above your furnace. In most newer systems, the button is often directly next to the blower motor, while in older systems, it may be harder to spot as it is sometimes underneath or behind the motor.
Checking your thermostat is the best place to start. Make sure it's set to “heat” and that you've set the temperature higher than the current room temperature. If that doesn't resolve the problem, try switching your fan to “on” to force the furnace to start working.
Most likely, your furnace is making a clicking noise and not providing heat because your furnace's spark igniter is trying to ignite your pilot light or burners but is failing to do so. In other words, there's an ignition system malfunction that needs to be fixed. Otherwise, your furnace won't start.
Can you DIY a furnace ignitor replacement? In short, yes, you can DIY a hot-surface ignitor replacement. It shouldn't be too difficult if you have experience fixing things around the house.
A multimeter can be used to help determine if a glow-bar style furnace igniter has sufficient electrical continuity – a continuous electrical path present in the part – for the igniter to function properly.
Remove the ignitor carefully by holding only the base. Avoid touching the ignitor surface with bare hands. Use compressed air to remove carbon deposits. Gently wipe the surface with a soft cloth or scuff pad until shiny.
For instance, the flame sensor is on the left side, while the ignitor is located on the right side of the burners. When the burners produce a flame, the rod-shaped protrusion detects it and sends an electrical signal to the furnace's control board, signifying that everything is functioning correctly.
The igniter glows red and then lights the burners in the gas furnace. Over time, the igniter is continually getting red hot and then cooling, creating stress on the element. Because of this, igniters have a 3-5 year life expectancy. They will eventually crack and need to be replaced.
A furnace ignitor replacement costs $100 to $250 on average. Most universal hot-surface ignitor prices are $15 to $35 for the part alone. Gas furnace ignitor prices are $20 to $100 for parts from the original manufacturer (OEM). The labor cost to replace a heater ignitor is $80 to $200.
The Short Answer Is: Warning signs of a bad furnace ignitor include the furnace not starting or heating, a noticeable clicking sound without ignition, or frequent short cycling where the furnace turns on and off rapidly. Additionally, if the ignitor appears cracked or discolored, it may need replacement.
If your gas furnace initiates the start cycle but doesn't fire up, it's likely because of a faulty, damaged, or dirty ignitor/sensor. This is a very common problem — you can try to clean the sensor and replace the ignitor.
Most modern gas furnaces can be reset by turning off the power, waiting around 20 seconds, then switching the power back on. Other furnace models may exit lockout after 1-2 hours and attempt to power on again.
If nothing's happening when you're expecting the whir of a blower, check the circuit breaker and fuse. At your electrical panel, make sure all switches related to the HVAC system are on. Reset any tripped breakers and replace all blown fuses, and your furnace should kick back on.
There are several reasons why your furnace may not turn on. The most common include a broken thermostat, gas line issues, clogged air filters, blocked ductwork, a tripped circuit breaker, and issues with the furnace itself.