# concord furnace wont run



## maxkilla96 (Oct 4, 2009)

Hi I have a concord 90 plus furnace that wont kick on. It gives me a code 3 which means pressure switch open with inducer on. I have 2 furnaces that are the same in the house and the 1 upstairs works fine but the downstairs unit doesnt. So i have used the inducer blower and the pressure switch along with the vacuum lines from the working 1 and still no luck. If i put the 2 purple wires together the furnace kicks on and runs but wen it shuts off it wont kick back on with the 2 wires together. I have cleaned the inducer blew all the lines out. I am figuring that there has to be a restriction somewere that i can not find. The inducer is not creating enuff pressure to the pressure switch or maybe to much. Thats were i am at so far any help would be greatly appreciated!!! Its starting to get cold Thanks


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## Plumber101 (Feb 25, 2009)

Since you probably don't have a manometer then this is a simple check. 

Remove the exhaust pipe off the inducer motor and try a call for heat to see if the furnace lites and runs.

If it does then you may have a restriction in the exhaust flue or a weak inducer motor

If it does not then you may have a pressure switch that has gone bad or a weak inducer motor


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## maxkilla96 (Oct 4, 2009)

i will try that but i used compressed air and blew threw that pipe and has good flow and i ahve used the pressure switch from my good running furnace and the inducer from the good running furnace and no luck. I even put the inducer and pressure switch i took off the non working furnace onto the 1 that runs and it still runs good. Any other ideas i have eliminated those possibilities so its gota be something infront of my face.


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## maxkilla96 (Oct 4, 2009)

i will try that but i used compressed air and blew threw that pipe and has good flow and i ahve used the pressure switch from my good running furnace and the inducer from the good running furnace and no luck. I even put the inducer and pressure switch i took off the non working furnace onto the 1 that runs and it still runs good. Any other ideas i have eliminated those possibilities so its gota be something infront of my face. also the chamber were the flame is produced kinda puffs and the eye glass shakes when it tries to kick on


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## GetYourShineBox (Sep 20, 2009)

if you took the inducer and pressure switch out of the non working furnace and put it another and the inducer and pressure switch worked then it could be the inducer relay coil and contacts on the board for the non working furnace.


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## maxkilla96 (Oct 4, 2009)

ya i did that and if i blow into the line from the inducer to the pressure switch and hold the pressure it kicks on and works but when the inducer is running i stick my finger by the hole were the vacuum line runs to the pressure switch i dont feel any air. Where exactly is the relay coil and the contacts you r talking about? Thanks i really really apreciate the help


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## GetYourShineBox (Sep 20, 2009)

on the ifc control board. do you have a multimeter?


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## maxkilla96 (Oct 4, 2009)

ya i have a multimeter and i know how to use it!! lol ohms resistance all the good stuff. but i actually just switched the circuit board and the lil box above it. Still the same. Im thinking there is some problem behind the inducer in that boxed in area behind it. You can hear it puffing and the pressure switch clicks on and off.


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## Plumber101 (Feb 25, 2009)

GetYourShineBox said:


> on the ifc control board. do you have a multimeter?


 
Why a DVOM?

You need a Manometer this is a pressure/vac problem. You need to measure the neg pressure off the inducer motor


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## beenthere (Oct 11, 2008)

Using an air compressor to check the flue pipes is misleading.
The inducer does not have the ability to push air the same way.

You may have a bad heat exchanger. Since you said it puffs when it does light.

Try getyourshinebox's suggestion.


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## maxkilla96 (Oct 4, 2009)

does the heat exchanger have anything to do with the inducer not creating enuff pressure to kick the pressure switch closed. And a manometer i have never herd of 1 of those the only thing i have is a vacuum gauge. but ya the inducer seems to not be givin enuff air to the pressure switch and i have no idea y i can kinda feel a lil air coming out the hole of the inducer that the line hooks up too. This furnace is not even a year old


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## beenthere (Oct 11, 2008)

Yes.

One of the things the pressure switch protects you from. Is a problem with the heat exchanger.
Is this furnace ran on LP/Propane?
If so. Has it ever run out of fuel.

Manometer is a device that measures air/vapor pressure. For a furnace. You need to be able to measure in tenth of an inch. Positive, and negative pressure.


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## maxkilla96 (Oct 4, 2009)

its a natural gas furnace so im assuming propane thats wat it smells like. But i dont know if the furnace has ever ran out i bought this house a few months ago and the furnaces were installed brand new. I dont know who installed or anything. Were is the heat exchanger is it easily replaced cuz i can try to take it off my rental unit furnace. No1 stays back there and thats the furnace that runs lol


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## beenthere (Oct 11, 2008)

Natural gas and propane are not the same thing.

You can't put a different heat exchanger in a furnace from a different brand. Or model size.


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## GetYourShineBox (Sep 20, 2009)

check the heat exchanger for a crack and determine if thats the problem or not and move on that. to do so disassemble the burner assembly and probably a panel thats covering the exchanger and put a light up in the heat exchanger with the lights in the room off and see if you see any light coming out of anywhere in the heat exchanger...

this is a heat exchanger...


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## GetYourShineBox (Sep 20, 2009)

or just call somebody who knows what they are doing


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## beenthere (Oct 11, 2008)

GetYourShineBox said:


> or just call somebody who knows what they are doing


Fort a heat exchanger inspection. Thats the best idea.


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## maxkilla96 (Oct 4, 2009)

so i had the heat exchanger checked out by a pro and it is in perfect condition. This furnace is brand new. So what could cause the inducer to not allow enuff pressure to the pressure switch could it not b spinnignfast enuff not enuff power to the inducer. I had this guy check the inducer as well and he found nothing wrong with it either. Like i said this is a brand new unit with all the parts brand new. Can any1 tell me were i can find a manual or a wiring diagram for the circuit board or the furnace itself????


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## beenthere (Oct 11, 2008)

Install manual, Or tech manual.

Did you ask him to find out what was wrong while he was there???


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## Flashheatingand (Sep 7, 2009)

Almost all furnaces have a wiring diagram on one of the door panels.


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## Flashheatingand (Sep 7, 2009)

If the furnace is brand new, call the installers. It is likely something due to the way the exhaust was plumbed, the condensate drainage, or combustion air.


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## harleygrl (Jan 14, 2014)

*Concord furnace pressure switch*

Hi I need to know asap if anyone has had trouble w/this. I am very upset that my NEW Concord furnace at the beginning of my 2nd winter with it broke down. It happened to be the coldest week we've had here as well in probably 5 yrs! I came home to a cold house and was told by a repairman i called there was a recall on the pressure switches for Concord? I can find no information and am going after Concord/Allied itself for the fact this NEW furnace broke during its' 2nd winter. I didn't appreciate getting sick from no heat, losing time and pay from work and paying $250 to get it fixed. I had emailed them and they said the warranty does'nt cover labor. I think that is a joke when the furnace isn't even 2 yrs old. IT was the pressure switch and my repair guy told me he has replaced a lot of these with Concord units...Appreciate any thoughts!!!


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## beenthere (Oct 11, 2008)

harleygrl said:


> Hi I need to know asap if anyone has had trouble w/this. I am very upset that my NEW Concord furnace at the beginning of my 2nd winter with it broke down. It happened to be the coldest week we've had here as well in probably 5 yrs! I came home to a cold house and was told by a repairman i called there was a recall on the pressure switches for Concord? I can find no information and am going after Concord/Allied itself for the fact this NEW furnace broke during its' 2nd winter. I didn't appreciate getting sick from no heat, losing time and pay from work and paying $250 to get it fixed. I had emailed them and they said the warranty does'nt cover labor. I think that is a joke when the furnace isn't even 2 yrs old. IT was the pressure switch and my repair guy told me he has replaced a lot of these with Concord units...Appreciate any thoughts!!!



Read the warranty paper. Its a limited warranty. Limited to the part only. Whether it breaks down after 2 months, or 2 years. 

Labor warranty is provided by the installing contractor. And then its usually only a 1 year labor warranty.


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## harleygrl (Jan 14, 2014)

*concord furnace*

Thanks for the reply - warranties seem to be good for not much if you have to pay labor so soon - i can understand maybe 5-10 yrs down the road - as i was told this part should've lasted at least 5 yrs -- not happy all around..


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## beenthere (Oct 11, 2008)

Thats why many recommend to a customer to buy an extended labor warranty.


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