Furnace Runs For A Bit Then No Fire - HVAC - DIY Chatroom Home Improvement Forum


Go Back   DIY Chatroom Home Improvement Forum > Home Improvement > HVAC

CLICK HERE AND JOIN OUR COMMUNITY TODAY...IT'S FREE!

Reply
 
Thread Tools Display Modes
Old 01-26-2013, 02:44 PM   #1
Member
 
Join Date: Jun 2009
Posts: 199
Rewards Points: 150
Default

furnace runs for a bit then no fire


hey I have a Lennox furnace, that the inducer motor will come on and spin for like 2 or 3 seconds and then shuts off. it will come back on after a few minutes and do the same thing again.I check the pressure, it is kicking in the pressure switch. on the schematic it shows a limit switch after the pressure sensor, if I take the wire off of that pressure sensor the indoor blower motor starts to turn instantly. in about 1 minute the inducer motor will spend and the furnace fires like normalit will run for about 10 or 15 minutes and then shut down. when it starts up it may or may not fire, if it does the burners will come on for about 1 minute and just before the blow motor comes on the burners go out. if I pull that wire off of that limit switch again it starts all over but never runs more than 15 minutes or so. I am NOT leaving that wire off I just momentarily take it off and put it back on when the blower motor starts.

the lights on the unit blink normal green no matter what happens
any clues what to test next or where to start?

Advertisement

wetbar is offline   Reply With Quote
Old 01-26-2013, 02:56 PM   #2
Member
 
Missouri Bound's Avatar
 
Join Date: Apr 2011
Location: Almost Arkansas
Posts: 2,764
Rewards Points: 2,000
Default

furnace runs for a bit then no fire


Any way you can post the schematic? How old is the furnace? Maybe a control board issue.

Advertisement

__________________
Do you want it your way or the right way?
Missouri Bound is offline   Reply With Quote
Old 01-26-2013, 03:19 PM   #3
Member
 
Join Date: Jun 2009
Posts: 199
Rewards Points: 150
Default

furnace runs for a bit then no fire


This should help

furnace runs for a bit then no fire-20130126_102831.jpg

furnace runs for a bit then no fire-20130126_102842.jpg
wetbar is offline   Reply With Quote
Old 01-26-2013, 03:36 PM   #4
Member
 
Join Date: Jun 2009
Posts: 199
Rewards Points: 150
Default

furnace runs for a bit then no fire


I have replaced "s10" - primary gas limit (looks like a normal limit switch) not sure what gas has to do with it, unless it just kills the gas. it is 160 degrees. I also replace s21
wetbar is offline   Reply With Quote
Old 01-26-2013, 07:28 PM   #5
Member
 
Join Date: Jun 2009
Posts: 199
Rewards Points: 150
Default

furnace runs for a bit then no fire


ok I have an update. I checked the lights again and they are blinking error code "Primary or Secondary limit open" . So I shorted all switches, one at a time to find the bad switch. gave same error on all until I shorted them all at once. I inserted a temp probe to make sure it didnt get sky high.The temps did get up to 150 degrees then gave another error code that says "Improper main ground or line voltage below 75 volts; OR: Broken ignitor; OR:Open ignitor circuit."
I checked the voltage and the ground. I'm not sure about the broken ignitor because it did ignite for 45 sec.

EDIT -
If this thing is over heating and popping the limit what would cause that? I checked the filters and fan motor. Both seemed OK.


Any clues?
wetbar is offline   Reply With Quote
Old 01-26-2013, 07:57 PM   #6
Member
 
Join Date: Oct 2011
Location: pa
Posts: 4,614
Rewards Points: 2,542
Default

furnace runs for a bit then no fire


if it has a/c coil could be clogged blocking air flow... setting off high limit..ben sr
ben's plumbing is online now   Reply With Quote
Old 01-26-2013, 10:06 PM   #7
Member
 
Join Date: Jun 2009
Posts: 199
Rewards Points: 150
Default

furnace runs for a bit then no fire


I'm not sure why I didn't think if that. thanks! Any clue why I would be getting that second error?
wetbar is offline   Reply With Quote
Old 01-28-2013, 08:48 AM   #8
Member
 
Join Date: Jun 2009
Posts: 199
Rewards Points: 150
Default

furnace runs for a bit then no fire


What is considered the :Broken ignitor circuit"? Just the wires from the board to the ignitor?
wetbar is offline   Reply With Quote
Old 01-28-2013, 12:29 PM   #9
Member
 
Join Date: Jun 2009
Posts: 199
Rewards Points: 150
Default

furnace runs for a bit then no fire


OK, I checked the coil and it looked good. (very clean) Now I am lost! Please help!
edit - I tried to check the gas pressure but the screw is stripped out and I could not remove it. would high gas pressure cause over heating?

Last edited by wetbar; 01-28-2013 at 01:14 PM.
wetbar is offline   Reply With Quote
Old 01-28-2013, 01:27 PM   #10
Member
 
JJboy's Avatar
 
Join Date: Oct 2010
Location: Austin - Texas
Posts: 1,402
Rewards Points: 500
Default

furnace runs for a bit then no fire


I think you found your problem.
__________________

**Always kill the power ** Hot air rises, but heat will always move from higher to lower temperatures. ** Real man shoot in manual. ** If it ain't grounded, it ain't dead.
JJboy is offline   Reply With Quote
Old 01-28-2013, 01:29 PM   #11
Member
 
Join Date: Jun 2009
Posts: 199
Rewards Points: 150
Default

furnace runs for a bit then no fire


What you are thinking high gas pressure?
I didn't think this was the problem because the flame looks perfect. Would high gas make the flame more orange?

Last edited by wetbar; 01-28-2013 at 01:31 PM.
wetbar is offline   Reply With Quote
Old 01-28-2013, 01:30 PM   #12
Member
 
JJboy's Avatar
 
Join Date: Oct 2010
Location: Austin - Texas
Posts: 1,402
Rewards Points: 500
Default

furnace runs for a bit then no fire


High or low pressure does that. You really need to check the gas pressure.
__________________

**Always kill the power ** Hot air rises, but heat will always move from higher to lower temperatures. ** Real man shoot in manual. ** If it ain't grounded, it ain't dead.
JJboy is offline   Reply With Quote
The Following User Says Thank You to JJboy For This Useful Post:
wetbar (01-28-2013)
Old 01-28-2013, 10:17 PM   #13
Member
 
Join Date: Nov 2012
Posts: 60
Rewards Points: 75
Default

furnace runs for a bit then no fire


sorry wrong post now I cant delete it

Last edited by subcool; 01-28-2013 at 10:31 PM. Reason: wrong post
subcool is offline   Reply With Quote
Old 01-28-2013, 11:46 PM   #14
Member
 
Join Date: Jun 2009
Posts: 199
Rewards Points: 150
Default

furnace runs for a bit then no fire


Hey how hot should the flue get? this one is hot like 150 degrees hot.
wetbar is offline   Reply With Quote
Old 01-29-2013, 05:43 AM   #15
An old Tradesmen
 
Join Date: Oct 2008
Location: PA
Posts: 26,419
Rewards Points: 4,488
Default

furnace runs for a bit then no fire


Quote:
Originally Posted by wetbar View Post
Hey how hot should the flue get? this one is hot like 150 degrees hot.
On a condensing furnace that is too hot. And can be caused by over firing, or not enough air flow.

Advertisement

beenthere is online now   Reply With Quote
Reply


Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Furnace never goes into high fire, why? tfunk HVAC 34 01-23-2013 07:18 PM
Gas Furnace - Only First Two Burners Fire (Video Included) mark2741 HVAC 11 11-20-2012 10:51 PM
What runs before furnace starts rosco HVAC 12 03-20-2010 11:57 AM
my furnace wont fire... please help! chrider88 HVAC 7 01-22-2010 10:43 PM
Problems with new furnace..Overheating, having to reset. Furnace too big? Tommy2 HVAC 41 12-01-2008 02:55 PM




Top of Page | View New Posts