Reinstalling Lion OS using recovery , will it erase my other partition(s) data?
The Lion Recovery HD can be a very misleading name. Especially if you're familiar with PC vender recovery solutions. The Lion Recovery HD [or disc] is, in functionality and feature, just like booting of an Mac OSX Installation Disc. 

When you boot into the Recovery partition [or disc] and start the process, you will be asked to select which disk you wish to restore [which actually means install to]. You will see a list of your three partitions to which you select your "Macintosh HD" partition and you're good to go. Any formating that may occur will only occur on your selected partition and not affect any other partitions.

You are safe to run the Lion Recovery Partition.