Heating/Cooling Fan Question

[fisher27]

My fan will not kick on when I set the fan to the "on" position on the thermostat. I like the fan to blow in continous mode for even heating/cooling distribution so I set it to cac at the limit control thingabob inside the furnace. Also, when I shut the fan down to change the filter and then power it back-up I sometimes have to pull on the belt to get the fan going. I have an old G11 Lennox furnace with a belt drive blower. I'm not sure where to start to fix the problem. As near as I can tell there are no capacitors that could be causing the fan to need assistance restarting. I suspect a relay to be the problem for why the fan will not kick on when the thermo is set to on, but I'm not really sure. I'm also not sure if the fan motor itself could be getting ready to die. D[?]oes anyone have any words of wisdom?

mike fisher
fishermj@flcc.edu

[16x80]

If you have to assit your motor to start then I would say you have a bad motor!

Question if you leave it alone and let the system turn on and off by itself will it start?

16x80

[fisher27]

Sometimes the motor will start other times not from a dead stop. Recently, the motor will not start sometimes when the air conditioning kicks on. You can hear the furnace attempt to kick the fan on a higher speed but the motor does not start. Even after I pull the belt the motor won't start. If I turn the power off to the furnace for about 30 minutes and then turn it back on the fan will then start. I'm more convinced every day that the motor must be shot. Thanks for your reply!

mike fisher
fishermj@flcc.edu

[16x80]

If you have bad start windings in your motor what will happen is they will allow the motor to start cold, once its warmed up it has a hard time starting!

Your guess would be right. If you do this replacement on your own, I would remove the motor and get the specs off of it. IE: HP, Rotation, RPM. Make sure you get a motor that falls right along with the old motor. It could be that you might not be able to find an exact match for your unit. RPM, HP, Rotation are ever so important! If you have trouble locating a part, Try some service men in your area that sell your product line.

Good luck and please keep us informed as to what you find out or get resolved!

16x80

[fisher27]

Well, I replaced the motor two days ago and all seems to be right with the world again. The furnace seems to be bahaving as I would expect it to, so the motor must have been the culprit. Had to make some special adaptations so that the motor would work with the mount that came with my furnace. Thanks 16X80 for your help.

mike fisher
fishermj@flcc.edu