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Ducane Gas Furance with Honeywell Ingnition Not Firing...

8001 Views 33 Replies 4 Participants Last post by  BDPNA
My Ducane gas furnace is refusing to light, and it's getting COLD in here! Would love to call a tech but all are on emergency-only service for the holidays and I just can't afford that right now. Any suggestions on getting it to light, even just once would be great!

Some background - 13 year old natural gas furnace, brand new with house. A couple months ago I noticed that the pilot was kicking on and I heard flame/heat for about 2-3 seconds, then I'd hear another noticeable click and it would shut off. Main circulation fan would never start. After disconnecting some cables and troubleshooting, it just sort of started working again. Fast forward to today...

The unit turns on but only the small fan in the middle, and I don't hear the honeywell ignition unit (upper center in photo) clicking or trying to fire at all now.

Last night, a friend advised that I look in the exhaust hose trap from that smaller black fan inside the unit (that t-junction down on the lower right), sure enough, sucker was full of water! I siphoned that all out of there and re-connected but still, no luck -- After that last night I did hear it attempt to fire up once again (the pilot) but now, when I turn the power back on, the inner fan runs, but I don't even hear the pilot attempting to light/click at all anymore.

Anything safe I can try to get some heat going for Christmas? I'd be most grateful.

Oh another question as well - Am I potentially doing harm to myself or the system to leave it running without the pilot lighting and heat flowing? Any gas risk by this happening? I don't smell gas but I assume it's flowing and without it being lit I'm not sure about the safety risk.

I'm not sure if this would have had any effect on why the igniter isn't even trying to start anymore, but a couple times I got lazy when I wanted to unplug a few things and shut off the unit using the red emergency shut off switch on the wall next to the unit. I've got it back on now, and am using the breaker to shut off power to the unit now when I am messing with it, but is it possible I have to reset something elsewhere since I had used that red emergency shutoff switch? Or a particular order I need to power/switch stuff back on? It's peculiar because yesterday, the Honeywell auto-ignite was at least trying to fire from the sound of it, today, it's not even trying at all.

Any help during this holiday weekend would be most appreciated!!!

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1) No danger and gas flowing when the pilot does not lite, there is a flame sensor to stop it. No harm by using that red wall switch

2) Shut off the power and CAREFULLY unplug and replug in those 2 wire connectors on the gas valve. One is for the igniter and the other supplies power to the valve. That gas valve had a bad history of failures and may be the problem. There may be a red led on the circuit board which gives you an error code when the problem happens. The code is on the back of one of the furnace doors and may be the lower ones.

3) About a dozen problems can occur to cause your situation and you may really need an experienced Pro to fix it. Not something I can talk you thru and you need special tools to check the pressure switch etc.
NO you don't that easily with that unit. The flame sensor is very tiny and not like a conventional one in my pic and is built into the pilot burner assembly and VERY difficult to get at on that unit. VERY easy to break the HSI hot surface igniter (glowing red part) when working with it. That is a very difficult job to do so you may get in over your head and break something but if you want to try go ahead. Check your venting outside for obstructions. Does it have a seperate intake and exhaust pipe outside or a round donut shaped one piece concentric unit? Either way check them carefully for blockage and if you have the concentric then you need to stick your fingers behind it and check for debris, spiders webs.
Unfortunately that unit is difficult to work on and I usually just replace the entire pilot assembly with the sensor and igniter as it gets rusty and corroded and it will take forever here to tell you what else goes on. Sounds like somethng is choking the flame/burner or tripping the pressure switches and that could be venting related or a dozen other problems.
See I told you Yuri would know. My unit is a Carrier and really easy to get to. I guess good engineering costs. Do what Yuri tells you from here on out. Im sure he has forgotten more than I will ever know about furnaces.
Done my share of roofing work, dealing with leaky flat roofs on a hospital etc and hated it, we had a fabric roof on the Convention Centre I used to work at . Can't imagine how long that will last compared to a conventional roof.
I think the tech guy said it was good for 20 yrs but what do you do after that. Rip it off. Didn't seem very durable to me.
DO NOT disconnect that hose. The pressure switch is a critical safety device for the furnace. I proves there is enough draft for the burner to fire safely and enough air for safe combustion. Bypass that and you will permamently damage the heat exchanger or worse. He should be checking it with a manometer and it sounds like you need a more experienced tech.
Welcome to my world. Troubleshooting is not an exact science or that easy and we cannot do it over the net all the time. If the switch has a rating on it like .48"WC then he should hook up a manometer to that hose and see if the pressure is OK. I have not seen that furnace for a few yrs and those Ducanes are a bit different in what they monitor the pressure on and how. The newer ones have one switch that does 3 functions. You really should find or get a troubleshooting manual to describe what those switches do to help him. It may be a bad switch and problem solved. Otherwise you really need a troubleshooting chart and it is in the install manual. The switch checks for venting obstructions, drainage issues (too slow), problems with draft thru the heat exchanger etc. I would have to be there to help more. See if you can find the troubleshooting info and post it here.
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