indoor blower not cutting off

[rickforeman]

my friend has a lennox blower unit and it does not cycle off, he has to unplug it for cooling and i think for heating also i'm not sure could this be the thermastat or the fan center?

[Diceman]

Does your friend have a computer and a phone?
It could be fan control set too low, could be a short, could be a few other things.

[chillbilly]

Probably a sequencer stuck in the closed position or a relay.

[appltech1]

Lennox has always had that problem and nobody sees it coming until it happens. Maybe you might interest them in a Trane or Goodman dialog. :cool:

[clubdoc]

i love the way you guys banter with each other like brothers...one who loves fords and the other chevy's

i'll go with the stuck relay as i had a lennox stuck "off" in the cool cycle. also, seen worn out thermostats (cool/heat switch) creating same "fan wont work" problem.

[polar air]

This is what I would do:
1) turn off the power to the AHU and disconnect the red wire (24v)on the t'stat.
2) turn AHU power back on. If the blower starts running, turn off power to AHU and check continuity on the normally open contacts of your blower control device. If you get continuity replace the device.
3) On the other hand, if the blower does not turn on (in step 2) then check the t'stat by either doing continuity checks or by replacing it.
hope this helps!!!!

[Roscoe]

"Plug it in Plug it out"

[Edited by pjs on 05-30-2004 at 06:35 AM]