Fan Shut Off When Heat Pump Comes On Troubleshooting - HVAC - DIY Chatroom Home Improvement Forum

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


Thread Tools Display Modes
Old 03-16-2011, 01:56 PM   #1
Join Date: Mar 2011
Posts: 1
Rewards Points: 10

Fan shut off when heat pump comes on troubleshooting


We're having a problem with the fan turning off when the heat pump comes on. I've replaced the motor, compacitor, and thermostat. But still the same problem. The fan works fine in emergency heat mode but when the Lennox heat pump comes on the furnace fan starts buzzing then turns off. Any suggestions as to what the problem may be that I can take a look at?



Parmleyhouse is offline   Reply With Quote
Old 03-16-2011, 04:53 PM   #2
Join Date: Oct 2007
Location: Manitoba, Canada
Posts: 400
Rewards Points: 380

How old is the air handling unit (furnace) you are working with? Sounds like it may be an older model that has a fan relay to start the fan in heat pump mode that isn't closing.

Is it by chance an electric furnace? Most have 2 relays to bring on the fan motor, one is 240 volt and turns on the fan when there is a call for emergency heat (through the sequencer), the other is operated off of 24 volts and gets it's signal from the thermostat (G terminal). Anybody tried changing the thermostat lately?


HVACDave is offline   Reply With Quote
Old 03-16-2011, 05:06 PM   #3
An old Tradesmen
Join Date: Oct 2008
Location: Somewhere
Posts: 34,409
Rewards Points: 7,808

Does the fan run when you turn the thermostat's fan switch to on?
beenthere is offline   Reply With Quote

furnace fan shut off

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
How to stop auxillary heat from coming on defrost cycle and limit auxillary heat use? twilightcall HVAC 34 12-28-2010 06:53 PM
New Heat Pump..questions? ddave23 HVAC 4 03-05-2010 05:13 AM
Heat pump vs in floor heat mugen HVAC 5 03-02-2010 08:18 PM
heat pump cut off set point oldswab HVAC 4 12-02-2009 02:09 PM
Heat Pump vs Aux Electric Heat batolson HVAC 16 01-17-2009 10:28 AM

Top of Page | View New Posts


Search Engine Friendly URLs by vBSEO 3.6.1