Family Room Fan Coil cont...
I was so happy to get this job completed, until I turned the unit on.
While running, it sounded like there were marbles inside making a loud clicking sound. I was so disappointed. Through the small access doors on the side, I tried to diagnose the source of the problem. I removed the drive belt to test the motor, and the motor was quiet by itself. Therefore the noise must be coming from the squirrel cage fan. But what could it be ? The shives (pulleys) were slightly loose so I tightened them up, but the noise was still there. The only thing left was the bearings, but why would a new unit need replacement bearings. I tried to remove them through the access doors, but there was not enough space. I needed to disconnect the unit and open the top plate. There are about 30 screws holding it together. It was no easy job. With the unit apart, I extracted the 2 fan bearings. They were not clearly bad. Sometimes they wiggle and the problem is obvious. I replaced them anyway. They were about $25 each. While re-assembling the unit I also bolstered up the motor mounting with an extra bolt just for the heck of it. Then I reassembled the unit, turned it on, and the noise was still there. I was fed up and had to live with the noise. Luckily we were only using that unit for backup heat so it didn't come on much. Through the rest of the winter we kept the heat way down to minimize use. I had failed, but I didn't know what else to do. There was no contractor to call, because I installed it myself, and if I called Trane, I am sure that they would say it was installed improperly.
Nearly a year later, in December of 2001 the problem got worse. It was starting with a loud screech and then quieting down to a rattle. More that once I jumped out of bed expecting a car to come through the porch windows. This was now clearly unacceptable.
Through the access doors I determined that the screech was from a loose drive shive on the motor. This wasn't too hard to fix, but the rattle was still there. I called my friend at Trane as a last resort. The only thing that we could come up with was that the squirrel cage was bad. Just guessing at this point, I had to continue to eliminate possibilities. The unit had to be disassembled again. I pulled the bearings out and this time there was clearly al least 1 bad bearing. I am told that the bearings should never have to be replaced. Then I found it.
The fan shive was loose on the axle. The hole was somehow ovaled, even though the set screw was tight it still wiggled slightly. Every 1/2 revolution the shive would shift to the other side, thus the rattling marble sound. I upgraded the shive to a taper lock style that really clamps down on the shaft. I had to get this part from Grainger in Clifton. I think it was about $60 for the new setup. I installed 2 more new bearings, and the new shive and put everything back together. By this time I am getting good at it, but some of the sheet metal screw holes are stripped. Those screws were probably not needed anyway.
Success !! I couldn't believe how quiet it was. Finally