furnace motor maintenance question

[Krystonia5]

My home has a 14 year old Carrier Night and Day gas furnace. I've noticed that the motor makes a high frequency humming sound that doesn't sound quite right, I believe the motor is slightly out of balance, or is not adequately lubricated. I have the owner's manual, and the procedure to remove the motor, clean and lubricate it, and put it back in sounds very straightforward. But I am hesitant to do it during the winter, in case I cause some problems when I work on it. Has anybody done this themselves, and it is there any risk of causing damage by inspecting, cleaning, and lubricating the fan assembly? Or should I just assume that some instability is normal, and wait until summer when i can do the repair at my leisure and have time to fix it further if I end up causing more harm than good?

Thanks, Paul

[Dr. Hardcrab]

Friends and/or neighbors.......

;-]

[davefr]

It depends on your situation. If you live in Fargo, ND and this is your homes only source of heat, I wouldn't screw with it until spring. (assuming it's failure isn't imminent). It a straight forward job but if you run into problems and need parts or professional help, January isn't the best time to get it from HVAC repairmen.

Are you sure the humming isn't comming from the LV transformer? I'd recommend you pull the air handlers panel and take a look inside. Does the fan rotate easily? Is there lateral play in the shaft? Does the motor come up to speed quickly? Can you pinpoint the source of the humming?

[JustCallMe Norman]

Like the above Poster said, suspect the transformer first. If the furnace is humming all the time even when its not calling for heat..then its the transformer because it is energized all the time. It the hum is ONLY when its calling for heat, then, it could be your draft inducer motor (exhaust motor) assuming you have a high efficiency furnace. It could also be your Main Blower motor. Id sit on it till Springtime..then have a go on it. However..if it becomes noticably louder between now and then...id call a Heating Service Contractor who will most likely replace the part in question.

[Stormin Mormon]

I've pulled and replaced several furnace fans. It can be a real nightmare to get the blower wheel off the shaft, and get it back in. There is very limited space, and it's real easy to bind the blower wheel on the housing.

Some blower motors have a couple long "straws" which allow you to add some oil without tearing it all apart. Be sure to use the correct oil for electric motors. The wrong oil is far worse than useless.

I remember the time about ten years ago, the blower fan in my trailer started to squeal. Near to drove me out of the house. Good squirt of oil, and it was fine. This at about 11 PM one night.