Fan won't work on Auto


  #1  
Old 12-23-17, 10:32 AM
K
Member
Thread Starter
Join Date: Dec 2017
Posts: 2
Upvotes: 0
Received 0 Upvotes on 0 Posts
Fan won't work on Auto

Recently the fan on my whisperheat by lennox stopped working. I've been trouble shooting and no remedies have worked. I started by replacing the blower motor itself as well as the capacitor. Upon further inspection the circuit board was visibly fried so I replaced that as well. After those replacements the fan will come on but only if switched to, "on," manually. I changed the high limit switch and tstat today. Nothing has worked to get my fan to come on in the auto position. Any thoughts??
 
  #2  
Old 12-23-17, 10:40 AM
PJmax's Avatar
Group Moderator
Join Date: Oct 2012
Location: Jersey
Posts: 65,930
Received 4,139 Upvotes on 3,717 Posts
Welcome to the forums.

Any thoughts??
Yes.... we need the model number off the ID tag inside near the burner.
 
  #3  
Old 12-23-17, 10:42 AM
K
Member
Thread Starter
Join Date: Dec 2017
Posts: 2
Upvotes: 0
Received 0 Upvotes on 0 Posts
M/n: G20q3e-75-6
s/n: 5897g 09112
 
  #4  
Old 12-23-17, 11:27 AM
PJmax's Avatar
Group Moderator
Join Date: Oct 2012
Location: Jersey
Posts: 65,930
Received 4,139 Upvotes on 3,717 Posts
Your blower is controlled directly from the control board. After a demand for heat..... the blower is preset to come on in 45 seconds. The shut-off time is user settable. If the blower doesn't come on in the heat mode.... there is an issue with the control board.

Another possibility is wiring error. The board supplies two blower outputs......
1) cooling and FAN ON speed.
2) heating fan speed.

You should see heat and cool blower connections. You can swap them to see if the heat works then. If you aren't sure..... post a picture here of your wiring and the board. How-to-insert-pictures

This should be the manual for you furnace and the blower info is on page 20.
Furnaces/Lennox_G20_IOM.pdf
 
 

Thread Tools
Search this Thread
 
Ask a Question
Question Title:
Description:
Your question will be posted in: