# Concord Furnace - Need help with Ignition lockout



## thakkd (Jan 11, 2010)

Hi,

I have a concord furnace (model # cg90tb075d16c) which is giving trouble since last week.

I noticed that the heat was not running even when the temperature was below what we set it to.
Went down and tried to force it and so it tries to start up and immediately shuts down.
The indicator light came back with LED code 7 i.e. Stopped due to ignitor lockout.

Also sporadically the heat would come on by itself and stays on until it reaches the desired 
temperature and then next time it tries to start again fails.

Based on what I could find online I cleaned the flame sensor but it does not work.

Is there a way to tell if the ignitor needs to be replaced?

Also can the furnace behavior be sporadic if the ignitor is an issue.

Thanks
Dharmesh


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## 68mmassey (Feb 10, 2010)

*same problem here*

I also have a Concord furnace that is doing the exact thing described in thakkd's post. 

Thakkd - can you tell me how you remedied this problem?

or

Can anyone else help me? 

(Its 15 degrees around here...need some heat soon.)

Thanks!


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## thakkd (Jan 11, 2010)

Hi,

Sorry to hear that but I will try and describe what I know?

In my case the furnance was not starting up at all as in it would try to start and fail almost instantly. So even though the LED says ignition lockout it ended up being a logic board issue. So I called up the heating guys and they replaced the card. The card was still under warranty so they only charged me the labor.

If you force the furnance to start and it takes about 20-25 seconds to fail then it might be the ignitor or the flame sensor. If that is the case then you can actually pull it out of the box and see if it lights up at all.

Another way to test it is to measure the current at the ignitor and see if the logic board sequence reached a point where it sends current to the ignitor. In my case none of these things were happening and how fast the system shutdown after forcing a startup indicated it is a logic board problem.

Hope you get heat back in your house ASAP!!



68mmassey said:


> I also have a Concord furnace that is doing the exact thing described in thakkd's post.
> 
> Thakkd - can you tell me how you remedied this problem?
> 
> ...


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## 68mmassey (Feb 10, 2010)

Thanks for your reply - I greatly appreciate it. 

Actually, mine is acting slightly different. (furnace is 4+ years old)

Let's say the thermostat says 60 degrees. If i set the desired temperature at 62 degrees, the furnace will ignite and blow hot for around 5 minutes. The blower will then shut off (and I assume, the furnace) for around 30sec - 1 min. Meanwhile, the thermostat is still at 60 degrees, but shows that the heat is still on. It will then start back up, but blow cool air. It may continually do this, since it won't ever heat the house up to the desired temperature. 

The problem occured slightly about a month ago, cleared up, and now is back. 

Any ideas?

(is concord a decent brand - I have a 3 ton unit and a 90% eff. furnace - just seems like it isn't cut out for the long haul)


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## thakkd (Jan 11, 2010)

Hmm...that is funny. No I am not sure what it could be but if I were you I would go down to where the furnace is when it is blowing hot air and see if everything is good. Then see is the furnace has stopped for some reason and the blower is still on (sounds like that to me but I am not sure if that is even possible.) If you are at 15 degrees I would suggest call someone to take a look because even if you figure out what exactly is wrong it is pain to get the parts to do the replacement. Most plumbing supply houses sell stuff only to licensed contractors.


68mmassey said:


> Thanks for your reply - I greatly appreciate it.
> 
> Actually, mine is acting slightly different. (furnace is 4+ years old)
> 
> ...


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## 68mmassey (Feb 10, 2010)

I have someone checking it out tonight...hoping for the best. 

Just trying to get ahead of the game. 

Thanks for your help!


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## thakkd (Jan 11, 2010)

BTW I found this which sounds more like your problem
http://www.diychatroom.com/f17/furnace-will-not-stay-5560/


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