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Home Heating Repair - How to Change Your Gas Furnace Igniter

You have run all the tests and they all point to your igniter being bad in your gas furnace.
Your purge blower runs, the power comes on to the igniter, but you get no glow from that little wonder. How can it be changed?

Changing the igniter on your gas furnace really is not all that hard. But it may require a bit of patience and some tools that can get into some very tight quarters. Some furnace manufacturers have design their units to make this job very easy. Some other engineers obviously have never got away from their desk and picked up a screw driver. Hopefully you are lucky enough to have one of the easy ones.

The higher the efficiency of your furnace the harder this job will be. Usually the 90+ furnaces will have the burner compartment sealed. You will have to get the covers off of the burner compartment to get to the igniter. On the 80%er’s the igniter will usually be somewhere on the burner nearest the center of all the burners. Make sure that you remove all power to your furnace before you attempt to remove the igniter. It runs on 110V power and will give you a good jolt if you touch it with power going to it.

Once you have located the igniter, you will need to find the screw or screws that hold the igniter in place. Remove or in some cases just loosen the screw and remove the igniter. Take careful note of the location and position of the old igniter so that you can reinstall the new one in the exact position as the old one. In most cases the wiring will just be a Molex plug that you can just unplug the old igniter and then plug your new igniter back into it.

Carefully position the new igniter into the same location and tighten the screw(s) that hold it in place. Plug the new igniter into the plug and replace the covers on the burner compartment if there is one.

Now you can turn the power back on to your furnace and try for ignition. Hopefully you get the glow and ultimately fire in from the burners. This will give you heat and make everyone happy!

http://www.fixya.com/support/r4015846-furnace_ignitor_care_home_furnace

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no blinks normal running igniter glows gas comes on wont run


Check for 24 volts across the gas valve when Ignitor is glowing. If no, bad board. If yes, bad gas valve or blockage.
On a call for heat, the 24 volt thermostat sends a signal to the control module. The control module will indicate a call for heat with a light on the control either blinking or remain solid depending upon model. The inducer (exhaust) blower will purge all gasses from the furnace and pressurize a pressure switch. Once the pressure switch tells the module to continue, the electronic ignition will energize and send 120 volts to the igniter. The igniter will glow and you will be able to see it if viewed thru the small inspection port. Once the igniter gets hot enough, it sends a signal to the module opening up the gas valve (24 volts). Either a pilot will come on or the burner tube will ignite then spread the flame to all burners. Lastly a safety sensor will be looking for a certain temperature within a few seconds and the furnace will continue to operate and the room air blower will turn on in a minute or two.

What could go wrong? The unit will not run if there is no signal from the thermostat (bad thermostat or broken wire), the control module does not sense a signal from the thermostat (bad control), the inducer does not energize (bad motor), the pressure switch does not close (blocked vent piping, bad switch, plugged condensate hose), the igniter does not energize (bad control, bad igniter), the gas valve does not open or there is no gas (bad gas valve, broken wire, no gas), the pilot does not light (dirty pilot), the burner does not light (bad burner, plugged orifice, not enough combustion air), the flame does not spread to each burner (bad flame spreader, dirty flame spreader, more bad burners), the flame safety sensor does not detect flame (dirty or bad flame spreader, bad flame sensor, broken wire, bad control), or the room air blower does not energize (bad fan motor, bad control).

Mar 05, 2010 | Goodman GMS90703BXA Heater

1 Answer

my furnace will not shut off on auto. the fan will not run when switched to on. what should I check?


Some new furnaces have a feature that when it has an issue, it starts the room air blower until you reset the thermostat or kill power to the furnace. Not knowing what you have for a system I can offer you only how a furnace works and what you could look for "generically".

On a call for heat, the 24 volt thermostat sends a signal to the control module. The control module will indicate a call for heat with a light on the control either blinking or remain solid depending upon model. The inducer (exhaust) blower will purge all gasses from the furnace and pressurize a pressure switch. Once the pressure switch tells the module to continue, the electronic ignition will energize and send 120 volts to the igniter. The igniter will glow and you will be able to see it if viewed thru the small inspection port. Once the igniter gets hot enough, it sends a signal to the module opening up the gas valve (24 volts). Either a pilot will come on or the burner tube will ignite then spread the flame to all burners. Lastly a safety sensor will be looking for a certain temperature within a few seconds and the furnace will continue to operate and the room air blower will turn on in a minute or two.

What could go wrong? The unit will not run if there is no signal from the thermostat (bad thermostat or broken wire), the control module does not sense a signal from the thermostat (bad control), the inducer does not energize (bad motor), the pressure switch does not close (blocked vent piping, bad switch, plugged condensate hose), the igniter does not energize (bad control, bad igniter), the gas valve does not open or there is no gas (bad gas valve, broken wire, no gas), the pilot does not light (dirty pilot), the burner does not light (bad burner, plugged orifice, not enough combustion air), the flame does not spread to each burner (bad flame spreader, dirty flame spreader, more bad burners), the flame safety sensor does not detect flame (dirty or bad flame spreader, bad flame sensor, broken wire, bad control), or the room air blower does not energize (bad fan motor, bad control).

Jan 18, 2010 | Honeywell Heating & Cooling

1 Answer

Model #GMPN100-4 Goodman furnace. Vent fan


The sequence of events for furnace operation is -

Fan purge for 30-45 seconds. During this time, a pressure switch is actuated by the running of the purge fan, proving the control board the purge fan is running.

After purge and purge prove, the hot surface ignition and or spark begins. After a few second delay, the gas valve will open. The control board then monitors for flame prove through another sensor located near the burners. If there is no flame within 3-5 seconds, the gas valve closes. It will repeat this process, usually 3 times, before it shuts the system down, which requires a power down of the system to reset.

I have seen trash get into the hose between the purge blower and the purge switch. But you could be having other problems.

Dec 17, 2009 | Goodman Heating & Cooling

2 Answers

Ruud furnace Model URKA A030jK08 Code opt 589


Flip the lower panel over and look for a wiring diagram. On that diagram there will be a diagnostic chart. Let me know what 5 blinks represent. Then I want you to read on.

On a call for heat, the 24 volt thermostat sends a signal to the control module. The control module will indicate a call for heat with a light on the control either blinking or remain solid depending upon model. The inducer (exhaust) blower will purge all gasses from the furnace and pressurize a pressure switch. Once the pressure switch tells the module to continue, the electronic ignition will energize and send 120 volts to the igniter. The igniter will glow and you will be able to see it if viewed thru the small inspection port. Once the igniter gets hot enough, it sends a signal to the module opening up the gas valve (24 volts). Either a pilot will come on or the burner tube will ignite then spread the flame to all burners. Lastly a safety sensor will be looking for a certain temperature within a few seconds and the furnace will continue to operate and the room air blower will turn on in a minute or two.

What could go wrong? The unit will not run if there is no signal from the thermostat (bad thermostat or broken wire), the control module does not sense a signal from the thermostat (bad control), the inducer does not energize (bad motor), the pressure switch does not close (blocked vent piping, bad switch, plugged condensate hose), the igniter does not energize (bad control, bad igniter), the gas valve does not open or there is no gas (bad gas valve, broken wire, no gas), the pilot does not light (dirty pilot), the burner does not light (bad burner, plugged orifice, not enough combustion air), the flame does not spread to each burner (bad flame spreader, dirty flame spreader, more bad burners), the flame safety sensor does not detect flame (dirty or bad flame spreader, bad flame sensor, broken wire, bad control), or the room air blower does not energize (bad fan motor, bad control).

Nov 23, 2009 | Heating & Cooling

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