Roof A/C noise

[tropical36]

Here's the deal. Both A/C's were running a couple of weeks ago, while DW was working inside. Today, I tried turning them on while exercising the generator. While the rear worked fine, the front would not start and the EMS shut down both. After switching to shore power which produced the same effect, I went to the roof and remove the cover where I found that the fan shaft was frozen. One turn on the shaft with a pair of pliers freed it and afterwards it worked OK, except that it now has a high pitched whistling sound that is somewhat irritating. I'm guessing that it's a bearing, which was the cause of the initial freeze up. If so, I really don't know what is the best thing to do about it. If it's something else, then I'm at a loss and hopefully some of you HVAC experts can provide some answers.

[TXiceman]

I bet you have a Dometic A/C unit. Fan shaft freeze up is fairly normal for these and Dometic will deny it. I have to run ours about every w 3 weeks to keep them free. I now have a stick that i can reach into the vents on the A/C and give the fan a push...starts right up.

Ken

[tropical36]

Quote:

Originally Posted by TXiceman I bet you have a Dometic A/C unit. Fan shaft freeze up is fairly normal for these and Dometic will deny it. I have to run ours about every w 3 weeks to keep them free. I now have a stick that i can reach into the vents on the A/C and give the fan a push...starts right up. Ken

Yep, DOMETIC, but this is the first time in three years of ownership for this. Thing is, it freed up easy enough, but now I have this irritating whistle in it, so I guess I'm going to dig a little deeper and see if I can't get some grease in there somewhere.
Like your idea of going through the inside intake to free it up and will probably have to do this on occasion, so thanks for that bit of info.

[tropical36]

UPDATE...
Well, I got it done but as per usual got in a hurry and didn't explore things a little further. The bearings are somehow floating in the case ends an appear to be wrapped type thing and almost looks like a flat spring that you often see. The motor is by A.O. smith and forgot to record more info than what I have from the name tag.
The other thing I should have done while on the bench was to completely remove the rotor from the stator and inspect it for any kind of rubbing, which would indicate another reason for locking up. At this point I could have also used some emery on these parts in case there was any rust.
I should have maybe soaked the whole end cap in a pan of hot oil like said. I did pack in a lot of heavy grease before putting in back together.
For removing the thing, you must first cut the wires inside the junction box, (wires are like new), then remove both fans, starting with the condenser end. Once thats done you loosen the clamp on the evaporator end and bang outward with the motor until the fan falls off inside the shroud. You have to be careful to go a little at a time here or when it flies off the unit, it will shoot backwards with the other end of the shaft banging against the condenser. I smashed up the fins a bit but it does seem OK.
Anyway, it's running now and most of the whistle sound is gone. Whats left is of a lower frequency and not so irritating. I hoping that the grease will work itself in there some more as it warms up, but that hasn't happened as yet.
Since I'm such a glutton for punishment, I'll probably have it out again before it's over with and depending on what else I might hear back from you all.