December 5, 2012
This question was posted 8 months ago, so I am sure the OP most likely found their answer by now. But, just in case anyone else is reading this with the same question, here's my response.
Here's what I just did with C350BN. I am no expert. I am a DIY'er that prefers to learn as I go. This was my first time changing out a bathroom fan. You're responsible for your own actions, and cannot blame me if you break yours in the process. =)
Before you start, compare the old motor and fan wheel with your new one. Verify that the fan wheel is the same size, and look under the fan wheel where the motor mounts to the metal frame. Verify that the two nuts are the same spacing apart. If this all looks correct, then continue reading.
I took two screwdrivers and put one under each side of the fan wheel to use as pry bars. I placed them so that they press against the metal frame when force was applied. I then lifted up on the screwdrivers and pried the fan wheel off of the shaft. It doesn't take much force. Mine slid off with ease. Then, you will see two nuts that hold the motor itself to the metal frame. Remove those and the motor is out. Do the same with your old unit (I had to cut my OLD fan wheel off with tin snips). Then, install the new motor into your frame. Snug up the two nuts, and lightly press the fan wheel back on. Now you have a new motor in the old frame.
As I said, this was my first experience with bathroom fan. I hope this info helps or at least gives you an idea of how to approach your situation.
2out of 2found this answer helpful.