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BillyHvac, Journeyman HVAC Tech
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Experience:  Endorsed for unlimited heating, cooling, oil burners, boilers, refrigeration, hydronics
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Rheem furnace igniter won't light up.

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The igniter on my Rheem furnace won't light up. I replaced the igniter and the air filter but no luck. Are there any troubleshooting tips? My HVAC guy can't get out til next week.

Already Tried:
replacing air filter (which was filthy) and the igniter, which did not look to be shorted out.

Hello, there is very good chance the limit is tripped. Do you have flashing light on the circuit board?
Customer: replied 6 years ago.
I did not see one but I can check again. Open the lower door and look at the red light on the upper right side?
look for a viewing window first, sometimes taking off the door clears the fault. I am looking up you manual right now . Would you like a parts manual to see where the various parts are?
Customer: replied 6 years ago.
Too late. I opened the panel. When I put the panel back on and turned it on again I see a little green steady light through the hole on the left side.
Ok no turn to heat function and tell me what the sequence is before it faults
Customer: replied 6 years ago.
blower starts, then click, long wait, click, another blower, and then nothing. Igniter does not get red/hot.
Ok behind the gas valve against the front firewall do you see a 2"x4" rectangle with 2 wires attached to it?
Customer: replied 6 years ago.
not sure. please be more specific
Ok, in the top section of the furnace, above the exhaust motor mounted flush to the front wall just a couple inches from the top of the furnace. I am downloading the parts diagram so you can see what I am taliking about.
Customer: replied 6 years ago.
Yes. There is a 1.5in square red circuit board type material with two wires. On red one going to the flame sensor

Ok, go to the link and click the rgdj parts , then next screen click download now. I had to download at a third party site.

Item number 15 is what we are looking for

Customer: replied 6 years ago.
OK, got it. What next?
we want to remove the 2 wires from #15 and tape them together so they make contact, but do not touch the cabinet of the furnace. Then we want to try to start again.
Customer: replied 6 years ago.
sorry> same thing. no ignition
ok put that one back and now the other limit. Dont worry we will get through quick now
Customer: replied 6 years ago.
thinkin ahead now huh?.....same thing with that limit?
Customer: replied 6 years ago.
they were the quick connect kind
ok end result is we havent started yet right?
Customer: replied 6 years ago.
We know what the problem isn't, sort of:)

Ok before we check pressure switch, reset furnace and set your hand on the gas valve I have a feeling we might be still having an ignition issue....

tell me if this happens ....

draft exhaust fan starts

after a while the gas valve clicks

and then the main blower kicks on.

Customer: replied 6 years ago.
there were two clicks on the gas valve before the main blower turned on. then long delay then shut off you happen to have a propane torch?
Customer: replied 6 years ago.
We want to mimic the hot surface ignitor ....once the exhaust fan starts hold the flame close to the ignitor, and when the gas valve opens and burner lights we will see if it gets past the 3 second trial. If this works it eliminates all limits, rollouts, pressure switch.
Customer: replied 6 years ago.
FIRE IN THE HOLE!!! What now? It's running.

Ok that just cleared everything as far as the only question is

is the ignitor getting 120v but is not glowing?

or is the circuit board not sending 120v. If you have a meter you can unplug the ignitor and see if t gets 120v during start up before the gas valve clicks. The good news is your close now. That is how I used to light furnaces when there was not an ignitor available.

Customer: replied 6 years ago.
OK. I will take it from here. Thanks for your patience. Since it is a new igniter, any adeas what would keep it from getting power? Is there a fuse or equivelant?

Npe, it either gets 120 and works..

gets 120 and doesnt work

or doesnt get 120v........I wish you luck

BillyHvac, Journeyman HVAC Tech
Category: HVAC
Satisfied Customers: 21933
Experience: Endorsed for unlimited heating, cooling, oil burners, boilers, refrigeration, hydronics
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