GUJ100D12-1A Armstrong gas furnace not igniting


Old 01-06-16, 07:18 PM
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GUJ100D12-1A Armstrong gas furnace not igniting

I have a natural gas firnace GUJ100D12-1A . The thermostat at the temp of the house turns the combustion fan and main circulating fan on. I don't see a spark. The igniter looks clean and silver in color.

My first guess is either something is not sending voltage to the igniter or the igniter is not sparking to generate a spark to light the flame. This has two electronic devices it has a blower control board and a honeywell control box that says time out on it. I'm not hearing any clicking of an igniter trying to start.

it's 20 degrees here any ideas of what parts I need to buy and what to check? I have a multi meter.


Last edited by Ken Heidenfrum; 01-06-16 at 07:41 PM.
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Old 01-06-16, 09:42 PM
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Welcome to the forums.

You won't see a spark. Your furnace uses a hot surface igniter that glows bright white to light the burner.

You've told us that the draft inducer is starting but you aren't getting any ignition. Since you know the draft inducer..... locate the rubber tube that connects at the top. Remove the tube and using a small drill bit or paper clip.... clean the tiny hole that passes into the blower. You need to push the clip in an inch or two to make sure the hole is clear.

Reconnect the hose and try the furnace again. Let us know what happens.
Old 01-07-16, 01:09 PM
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Very likely the reason that the ignitor doesn't turn on is that the pressure switch isn't closing. Use a multimeter to see if the 24 VAC is being turned on by the pressure switch.

If not, you need to determine what defect in the furnace combustion and venting systems is causing the pressure switch to stay open.

Hint, it's almost never a bad pressure switch. Don't waste time and money by replacing that.
Old 01-12-16, 08:45 PM
Join Date: Jan 2016
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Sorry guys for not getting back, I could not log in but i am the Ken Heidenfrum that made the original post, Well first the bad news, I panic'ed and ordered a replacement module for the S8600C, it''s obsolete so I bought this: Honeywell S8610U3009 Furnace Intermittent Pilot Control - Replacement Household Furnace Ignitors -

and this:

It looked a lot different and no wires came with these and also my old one has a spark and a sensor and this one just had a spark/ sensor tab so I panic'd again not knowing what to do.

So for the good news, I decided to look back at this forum and see if anybody replied. I did what PJ max said and I took a torch tip cleaner and rodded out that barbed hose fitting. I had to almost saw thru the darn thing, there feels to be an obstruction in the port... The torch tip cleaner is ribbed so it saws thry, but it never really seemed to be fully open, it seems to hit something. So I quit rodding out and gave it a try.

I'm thinking to myself this is too easy.... there is no way this will work because the port seems still obstructed.

I started up the furnace and low and behold bright blue clean fire and warm toasty heat! Turning off the electric heater and 23000 BTU kerosene heater now in this 3 degree cold weather. House really warmed up fast. I cleaned my return vents and changed the filter for good measure. I'm really excited this worked out. It makes no sense to me how you guys knew it was either the blower port or the pressure switch. I was sure it was the module or the spark ignition set up.

2 questions I have for the future if you know the answer it's appreciated: The port in the barbed fitting was tight, should I drill it out or rod it out more because it sort of hits something when I poke it in and out?
and second question, if I ever have to use these parts i bought, what part do I need to connect the spark ignition set up to the module? Do I need to buy a universal connector like this?

I don't know how to thank you guys, you are a god send, may good karma come across your paths and good luck come your way. I hope you win the billion dollar powerball!

Thank so so much! I am at a loss for words how to thank you.


Ken Heidenfrum

Last edited by Bengal Sniper; 01-12-16 at 09:09 PM.

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