Have a Hampton Bay ceiling fan that is not working (hasnt since we moved in). The other fans throughout the house have remotes, but this one did not come with one.
How do I know which remote to get if I don't know the model number? Is it possible that it does not work because I don't have the remote??

Yes.. unfortunately, I've had the same experience. I don't know about the remote because I didn't use it, but the fan is hardwired to the remote (receiver on the fan), and that's the only way you can turn on or off... I would take a picture of the fan, take it to home depot, or wherever you bought the fan and tell them you need a replacement remote. The only way to get the fan turned back on is to hardwire it to a switch...

Thank you!! I will do that!

You are very welcome!

As a test, drop the ceiling plate on the fan without a remote transmitter and see where the DIP switches are set on the receiver. Then set a remote transmitter to the same DIP setting. It may work the fan. Many transmitters and receivers are the same frequency so setting the DIp the same basically lets them interchange.