Lennox Furnace Not Working When Very Cold - HVAC - DIY Chatroom Home Improvement Forum

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


Thread Tools Display Modes
Old 02-11-2010, 09:18 AM   #1
Join Date: Feb 2010
Posts: 1
Rewards Points: 10

Lennox Furnace not working when very cold

I have a house that was built in 2005 with a Lennox gas furnace. When the temp out side is cold, but above freezing, the furnace has no problem keeping the house warm and to the temperature the thermostat is set at. The problem is that when it gets really cold(usually 20's or below, especially at night) when the furnace has to work more to keep the house warm, it'll stop coming on and the temperature will drop, and the thermostat will even register that drop(showing the temp 65 degrees when it is set to 72), but still no heat turned on. Turning it off and back on will kick the furnace back on, but most of the time it only runs for a minute before stopping again(rarely it will stay on, but that's usually in the morning when it's been off for a long time).

At first I thought is was the thermostat since with had a similar problem at our old place with the A/C that required a new thermostat, but I replaced it and it still doesn't work.

Any ideas of the problem and how to fix it? Is this something I would be able to fix?


bsharitt is offline   Reply With Quote
Old 02-11-2010, 09:38 AM   #2
An old Tradesmen
Join Date: Oct 2008
Location: Somewhere
Posts: 29,996
Rewards Points: 11,464

Lennox Furnace not working when very cold

Probably haven't had the thing serviced recently.
So a guess would be the drain system if its a 90% furnace.

Next guess would be your using 3M filtrete air filters. Use a less restrictive one.


beenthere is offline   Reply With Quote
Old 02-11-2010, 06:58 PM   #3
Join Date: Oct 2009
Location: Nebraska
Posts: 2,362
Rewards Points: 1,000

Lennox Furnace not working when very cold

Sounds like a dirty burner and flame sensor problem. System locks out after so many attempts to light and not recognizing a flame.
Marty S. is offline   Reply With Quote

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
Lennox Furnace problems boolean HVAC 21 11-19-2012 07:45 PM
Lennox Elite Series Furnace Problem steges HVAC 7 11-06-2010 03:49 PM
new furnace - house is STILL cold qchawkfan Building & Construction 6 01-11-2010 10:30 PM
Weather King Furnace Not Working jbickmann HVAC 1 10-22-2009 08:53 PM
Flooring cold from furnace intake flipper_79 Building & Construction 1 01-25-2009 12:24 PM

Top of Page | View New Posts