Lennox Furnace - No Heat - HVAC - Page 2 - 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 10-28-2009, 07:15 PM   #16
Newbie
 
Join Date: Oct 2009
Posts: 20
Rewards Points: 10
Default

Lennox furnace - no heat


Quote:
Originally Posted by yuri View Post
The one above the burners and pushes the smoke to the chimney.
Yep, that one works.

I thought it was called in inducer fan - is it not?

Edit: although it does run, it only stays on for a few minutes after the furnace attempts to start.

Advertisement

Greenlawnracing is offline   Reply With Quote
Old 10-28-2009, 07:24 PM   #17
Hvac Pro
 
Join Date: Nov 2008
Location: Winnipeg, Canada
Posts: 10,038
Rewards Points: 714
Default

Lennox furnace - no heat


ventor fan/inducer fan same fan different techs call it differently. After the ventor fan starts the pressure switch closes and then the igniter is energized. If the switch does not close then the board show an error code. Is that happening? code is on the back of one of the doors. led flashes. Remove the smokepipe from the top of the furnace and look for a dead bird. Yes, I am serious, they fall in and can block the pipe and cause a problem.

Last edited by yuri; 10-28-2009 at 07:27 PM.
yuri is offline   Reply With Quote
Old 10-28-2009, 07:34 PM   #18
Newbie
 
Join Date: Oct 2009
Posts: 20
Rewards Points: 10
Default

Lennox furnace - no heat


Quote:
Originally Posted by yuri View Post
ventor fan/inducer fan same fan different techs call it differently. After the ventor fan starts the pressure switch closes and then the igniter is energized. If the switch does not close then the board show an error code. Is that happening? code is on the back of one of the doors. led flashes. Remove the smokepipe from the top of the furnace and look for a dead bird. Yes, I am serious, they fall in and can block the pipe and cause a problem.
Just tried that - no bird, just one dead roach. The fan blades appear to be moving properly.

There is no error code, which confuses me. Because the igniter is not being energized and the gas is not being lit - I would have thought that I'd get an error code.

I did connect my multi meter to the pressure switch. The left lead reads 27v, and the right lead reads .8v.
Greenlawnracing is offline   Reply With Quote
Old 10-28-2009, 07:44 PM   #19
Hvac Pro
 
Join Date: Nov 2008
Location: Winnipeg, Canada
Posts: 10,038
Rewards Points: 714
Default

Lennox furnace - no heat


You probably have a bad circuit board. It definetley should show you an open pressure switch code. Try cozyparts.com for Lennox parts or a Lennox dealer.
yuri is offline   Reply With Quote
Old 10-28-2009, 07:51 PM   #20
Newbie
 
Join Date: Oct 2009
Posts: 20
Rewards Points: 10
Default

Lennox furnace - no heat


Quote:
Originally Posted by yuri View Post
You probably have a bad circuit board. It definetley should show you an open pressure switch code. Try cozyparts.com for Lennox parts or a Lennox dealer.
Is there a way I can test the board to confirm its bad before I buy a new one?
Greenlawnracing is offline   Reply With Quote
Old 10-28-2009, 08:07 PM   #21
Hvac Pro
 
Join Date: Nov 2008
Location: Winnipeg, Canada
Posts: 10,038
Rewards Points: 714
Default

Lennox furnace - no heat


Nope. All the codes should be on the sticker and they never fail to show up on a board. Especially the pressure switch code.
yuri is offline   Reply With Quote
Old 10-29-2009, 11:24 PM   #22
Newbie
 
Join Date: Oct 2009
Posts: 20
Rewards Points: 10
Default

Lennox furnace - no heat


Fixed!
I went to the supply house to get a new tube...they didn't have the exact tube that I broke, just a generic one that wasn't nearly as stiff and had a larger interior diameter.
I had a guy come over to look at it tonight. Before I put the new tube on he had me run a wire into the inducer fan....guess there had to have been something tiny plugging it up. I didn't feel or see anything, but it fired right up.
The high heat tube that Lennox used is different than the one I bought today...the one I got kinks easily and required me to reposition the pressure sensor. Stupid replacement tube from Lennox is $25!

Still baffled as to why I never got any trouble codes.
Greenlawnracing is offline   Reply With Quote
Old 10-30-2009, 04:41 PM   #23
Hvac Pro
 
Join Date: Nov 2008
Location: Winnipeg, Canada
Posts: 10,038
Rewards Points: 714
Default

Lennox furnace - no heat


That is very strange. Good to know in case I run into one. Probably a bad batch of boards from whomever made them.
yuri is offline   Reply With Quote
Old 10-30-2009, 05:04 PM   #24
Still Learning
 
Join Date: Oct 2009
Location: Los Angeles
Posts: 338
Rewards Points: 250
Default

Lennox furnace - no heat


What kind of tube are you talking about that you replaced? I don't think i have ever heard of a high heat tube.
thehvacguy is offline   Reply With Quote
Old 10-30-2009, 06:58 PM   #25
Newbie
 
Join Date: Oct 2009
Posts: 20
Rewards Points: 10
Default

Lennox furnace - no heat


Quote:
Originally Posted by thehvacguy View Post
What kind of tube are you talking about that you replaced? I don't think i have ever heard of a high heat tube.
The orange tube is the original one that I tore while removing. It was basically molded to fit perfectly. I replaced it with the black tubing, but it isn't nearly as thick and kinks easily. I had to move the pressure sensor to make it work, and I'm worried that it will melt as I don't know if it can withstand the heat.

I'll spend $25 if I have to...but can you get a replacement somewhere else? $25 from cozyparts just seemed pretty high for a little piece of rubber.






Greenlawnracing is offline   Reply With Quote
Old 10-30-2009, 07:05 PM   #26
Hvac Pro
 
Join Date: Nov 2008
Location: Winnipeg, Canada
Posts: 10,038
Rewards Points: 714
Default

Lennox furnace - no heat


It is SILICONE hose and not rubber and the stuff costs me about $10/foot. Buy it or it will melt. Too bad you don't live nearby, I have lots of those leftover from other jobs.
yuri is offline   Reply With Quote
Old 10-30-2009, 07:22 PM   #27
Newbie
 
Join Date: Oct 2009
Posts: 20
Rewards Points: 10
Default

Lennox furnace - no heat


Any place I can buy something similar? Like an autoparts store?

Any chance you want to ship me a piece?
Greenlawnracing is offline   Reply With Quote
Old 10-30-2009, 07:22 PM   #28
Still Learning
 
Join Date: Oct 2009
Location: Los Angeles
Posts: 338
Rewards Points: 250
Default

Lennox furnace - no heat


So pretty much the tube allows the heat from the vent to flow to a limit switch?
thehvacguy is offline   Reply With Quote
Old 10-30-2009, 07:24 PM   #29
Hvac Pro
 
Join Date: Nov 2008
Location: Winnipeg, Canada
Posts: 10,038
Rewards Points: 714
Default

Lennox furnace - no heat


If it is the right diameter and made from silicone it will work. The Lennox one is better because of the square shape/prevents kinky/kinking.LOL.

The tube goes to a pressure switch which proves the ventor fan is running by the vacuum the fan draws.
yuri is offline   Reply With Quote
Old 10-30-2009, 07:29 PM   #30
Still Learning
 
Join Date: Oct 2009
Location: Los Angeles
Posts: 338
Rewards Points: 250
Default

Lennox furnace - no heat


The pressure switch is normally open or normally closed?

Advertisement

thehvacguy is offline   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
carrier/payne furnace heat exchanger issues gomongo1 HVAC 9 11-29-2014 09:29 PM
Lennox Furnace G27M Series Unreliable operation: pressure switch or else? sheppard1977 HVAC 7 01-14-2013 06:42 PM
Ducane Furnace - no heat dave_in_waterloo HVAC 4 09-19-2012 10:41 PM
Urgent! House Cold, NO heat, pilot lit (Lennox) ThatGuy23 HVAC 15 02-05-2009 10:11 PM
For all you Lennox owners ibwahooka HVAC 9 11-23-2008 05:06 AM




Top of Page | View New Posts