# Ducane Gas Furnace fails to stay on



## franko (Oct 24, 2006)

I tried to start my Ducane furnace recently. 

I turned on the breaker, turned on the burner On/Off switch, turned on the furnace on/off switch and turned on the gas. 

While leaving he top inspection pannel off I called for heat. 

The unit's exhust blower goes on and the furnace ignition element glows for a few seconds. 

After a few seconds the gas burners ignite.

After about 2-4 seconds the burners shut down. 
This cycle repeats. 

The furnace burners do not stay on to heat the house. 

Any sugestions would be appreciated.


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## #CARRIERMAN (Oct 18, 2006)

Hi franko

Pull and clean your flame sensor. This is the metal rod opposite of the ignitor. Shut power off to furnace before removing this rod. Use a wire brush DO NOT USE SANDPAPER! Let me know if this doesn't work, I will need a little more information.

Good luck.
RUsty


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## franko (Oct 24, 2006)

*Thanks*

Dear Rusty

Thanks. It worked like a charm.

I'm not sure why since there did not appear to be any visable build up.

Thanks Again

Frank


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## baseball27 (Feb 26, 2008)

Hey usually some manufactures recommend using sand cloth and then going back over with a wire brush and thats just a suggestion. Glad to see you got it running.


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## barbara aguirre (Oct 4, 2008)

Thank you, I have been trying to figure out this same problem myself!


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## will3 (Oct 28, 2008)

I need help with my ducane furnace not igniting. I Have changed the fan ignition board and checked the connections, still no flame from the igniter. I have also checked to see if the igniter was bad but it's still in good order. Help its cold!


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## dac122 (Sep 5, 2008)

will3 said:


> I need help with my ducane furnace not igniting. I Have changed the fan ignition board and checked the connections, still no flame from the igniter. I have also checked to see if the igniter was bad but it's still in good order. Help its cold!


What made you assume the board was bad? How do you know the igniter is still in good order? Is your draft inducer motor running?


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## will3 (Oct 28, 2008)

yes its still blowing


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## dac122 (Sep 5, 2008)

What's the unit's efficiency. What you checked and what else are you noticing? Have you checked chimney or intake (if >90+AFUE) blockage? What's the voltage to the igniter? Is your pressure switch working? Have you checked and cleaned the temperature sensor?

Again I'll ask: What made you assume the board was bad? How do you know the igniter is still in good order?


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## will3 (Oct 28, 2008)

I've checked to see if current was flowing through the igniter with a voltage tester. I have noticed that I wasn't getting any voltage from the igniter board (Honeywell). I have checked the chimmney and performed a flame test to see if any pull was taken place. Should I switch out the ignition board thats connected to my gas line?


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## dac122 (Sep 5, 2008)

Thought you already replaced the control module? How many boards you got in that thing? :confused1:

Is this an 80 or 90 AFUE furnace? Did you check your pressure switch or switches? Did you check the high temp limit switch?

At least we know you igniter is probably not the problem.


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## ostromk (Jan 17, 2009)

i am haveing the exact same problem as described in the first post to the T how do i get the flame sensor out to clean it


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## dougsage (May 1, 2011)

Hi - Sort of the same problem, exhaust blower comes on but the ignition element does not glow. Checked voltage - only 2.5 volts. Any thoughts for me?
Doug


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## Ducthunter (Mar 26, 2011)

dougsage said:


> Hi - Sort of the same problem, exhaust blower comes on but the ignition element does not glow. Checked voltage - only 2.5 volts. Any thoughts for me?
> Doug


2.5 v to the igniter from the board? If so probably bad wiring or board, most likely the latter


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## #CARRIERMAN (Oct 18, 2006)

*Ducane frunace fails to stay on*

Hi to all, it has been a while for me here. I have missed all you Ladies and Gentlemen. To help answer your question you may be working at the problem from the wrong end. The ignitor not coming on can be caused by a multiple of failures. Take your volt meter and insert a lead in each of the wires located at the plug. Start furnace into heating cycle, it could take as long as 1 1/2 minutes for you too get a reading at your meter. You will only show 120 volts for about 30 to 45 seconds. Unless this is a Ducane with the Honeywell smart valve system. Then you will read voltage about 30 to 45 seconds after inducer starts. If all safety devices are closed and pressure switch is functioning properly you will get a voltage reading for about 20 seconds. If you are getting voltage, ignitor is bad. If not, check all limit switches and pressure switch for proper operation. Most likely you will find rollout limit bad, (next to burners around burner box) or vestiblue limit, (black or brown limit in middle of furnace approx 2"X4"). Good luck, leave me a little more too work with if this doesn't work.

Rusty


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## phil d (Dec 3, 2011)

Hello, we need help ASAP, no heat now.
Have Ducane furnace MP9A075BU converted to LP, replaced Honeywell smart valve, ignitor is working, pilot only stays lit for at most one second, then goes out. 

This thing has an ignitor, which lights a pilot light, which lights the burner. 

HVAC person has checked both (only two safeties and the pressure switch) and all checked out OK. Pilot tube had cracked and was replaced. Hvac took pilot tube out and there plenty of gas pressure being supplied.
Any suggestions would be appreciated, we are working on the unit as I type.
thanks!


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## yuri (Nov 29, 2008)

pilot burner may need replacing. orifice is probably partially plugged. not easily field cleanable, need special orifice bit and it usually bends and gets damaged in the removal process. too small of flame due to orifice restriction.


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## phil d (Dec 3, 2011)

hi thanks for the reply. I spoke with the tech (a friend) and we are not sure if you mean the bit gets bent or the orifice tube gets bent.
Do you have an idea how to fix ASAP? can we use solvent to clean, or tiny drill bits (I have) to clean the orifice?

My son's family is cold, including my 2-year old granddaughter, I've offered to put them up over the weekend. He is very strapped for money, emergency fees are horrific. 

I would be happy to call you to discuss. I can send my number if you prefer. very much appreciate your reply, concurs with another local person that offered help.

--Phil


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## yuri (Nov 29, 2008)

If you have soft hands and are VERY careful you can carefully dismantle the pilot burner. Must be VERY careful how you remove it as it is very easy to break the igniter. Unscrew the aluminum pilot line from the burner use a 7/16 box end wrench so it does not get crushed/warped and carefully poke the orifice out, remove it with a piece of wire if it is not too stuck in. This is where it can get damaged as it is made from soft aluminum. If it comes out you can clean the inside with a piece of wire. The actual orifice hole is VERY small .010 for propane I believe. If you enlarge it then the flame will be too big. There are special tradesman orifice bits but I just replace the orifice and burner so I don`t get callbacks etc. I will hang in here and try help you. When it comes to kids I care a lot.


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## phil d (Dec 3, 2011)

*Yuri, need to leave soon*

Hi Yuri,

I must leave soon, but I will check later. They intend to remove orifice tube and will try cleaning it. The tech needed to move on to his next job for today. If you want my private email address to go offline, I can read that away from my computer. I don't see an option for replies to go to my email address, but I can try to access the site on my "smart" phone.


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## phil d (Dec 3, 2011)

just saw your reply, will stick around a bit. I will forward info, but I do need to go elsewhere soon.
thanks.


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## yuri (Nov 29, 2008)

I do my replies in the forum so they can help others.


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## phil d (Dec 3, 2011)

I m forwarding this thread, and the link to the forum, and my son will join and reply directly. He may not be home for an hour or more, so if you need to leave and can check back later, that would be great. Thanks again.
--Phil


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## yuri (Nov 29, 2008)

I should be here unless my better half decides otherwise.:laughing:


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## phil d (Dec 3, 2011)

Hi Yuri, sorry I didn't get back to you sooner, I've been down with a bug. My son's furnace has been repaired.

It turned out to be the orifice. This was after the smart valve was replaced--not sure if it needed to be replaced or not.

First HVAC from local highly regarded company recommended replacing Smart Valve for $525, replacing the LP Conversion kit (price and labor not determined). Second HVAC charged cost on Smart Valve ($160) orifice (at cost) plus time.

Thanks so much for helping. This initially stumped a couple people.

--Phil


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## yuri (Nov 29, 2008)

Thanks for letting us and others know. There is NO substitute for experience and I learned EVERYTHING the hard way. To bad a lot of these young techs and some old ones too are just "parts changers". 

Glad it got fixed and I hope you and your nice family have a Merry Xmas.:santa::yes:


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