I am replacing the remote on a fan that was in the house I bought 5 yrs ago. I don't know the model number. The old fan has a remote controller located below the fan and has a model no - 'UC7051R mas. Lamp Watt 250 Watt.'

The top of the fan has two wires connected to house power. All other wires which control the lights and the fan come out of the post below the fan and above the lights. There is a connector with seven wires attached.

How do I rewire for a new remote from hampton bay ?

This could be a mess. Are the 7 wires marked, numbers, colors, etc. The new remote should have its contacts or wires identified. You could be lucky and the new remotes will use the same color code.

If the remote receiver is located "below" the fan-- as in, in the switch housing of the fan-- it's probably not designed to be replaced with a receiver other than another one from the same manufacturer. I take it the fan manufacturer is not marked anywhere? Perhaps if you took a picture I could identify it. Or are you saying it is a Hampton Bay fan? I took your post to mean only the new receiver was Hampton Bay and you would not identify the fan.

Why are you replacing the receiver?

More information on ceiling fan remotes:

http://www.ceiling-fans-n-more.com/ceiling-fan-remote-controls.php

I believe the UC7051R is product specific, and you should look for the same replacement unit. I found one cheap on Ebay recently, but what I wanted was a generic one with pigtails.