HVAC Fan not running.

[D.McDonnel "Mac"]

I need some help from you motor savy members. I came home last night from being gone for 4 days and the furnace blower fan was not running nor would it start. Because I live in an older house we leave the fan on all the time to keep the house temps a little more even. I did not turn it off when we left, I just lowered the temp setting. Unless the electricity went off while we were gone (no evidence as no clocks were blinking) the fan stopped while running.

Current symptoms:
- fan freewheels and coasts nicely with the power off of it. I recently (2 months ago) removed the fan assy, cleaned and lubricated it after an incident where the fan wouldn't start. The motor needed lubed and I cleaned everything while it was out. Function returned to normal after that incident.

- As fan is freewheeling in the proper direction if I kick the power on (using safety interupt switch as I done many times in the past) the motor/fan stops and is very hard to turn as if it is held in place magnetically. To me this eliminates the start capacitor as a possible culprit and points to a bad motor.

I am going to work on it this evening. Is there a way to check the start capacitor to be sure? Any other motor checks I can make? I guess I should pick up both on the way home and try the capacitor first. I really don't want to call the HVAC repairman in on this if I can avoid it.

Thanks in advance

Mac

[Tyler Howell]

Sounds like control and supply AOK and cap too for that matter.

The resistance on the motor free wheel with power supplied is my guess.

I'm thinking windings on motor.

To check a Cap: Power Removed, allow to discharge. Lift one lead. Keep your fingers out of there. Power Removed. You may want to short the leads to make sure it is discharged. Ohm meter across leads. Hi Resistance setting. You should see a brief kick and then open ckt. reverse polarity on meter same thing. All this tells you is the Cap is not shorted and has some capacity. Leaking or oozing gunk is a bad sign. Did I mention Power Removed???

Good Luck, I'd be looking at the motor.

[D.McDonnel "Mac"]

It was the fan. I replaced it last evening. It's a little noisy which I suspect is installation related. I'm going to recheck the install tonight and make sure everything is lined up okay and not vibrating.

Thanks

Mac