Sell house - can I expense remaining balance of asset (HVAC/furnace) not fully depreciated

I recently installed a couple HVAC/furnace units for a couple of my rental units within the last 3 years.  Since the prices were around 7K for each property I depreciated them on my tax returns (show up as a separate asset) at 27.5 years.  I am thinking of selling these houses soon and was wondering if I am able to expense the remaining balance (undepreciated amount) of the furnace/HVAC systems at the time of sale.  For example, if I paid 7K and my remaining balance to be depreciated is 6.2K can I expense that 6.2K in the year that I sell the rental property.  If not, how is this 6.2K reflected in my tax returns during the year of the sale?

 

Regards

 

Dave