what is the function of this line at bottom of water heater?

[mszenas]

I'm replacing a fully functioning WH due to age. large, one story, 4/3 house with master with big tub on one end of house. It appears there is recirculating plumbing, I think, see pic of top of tank showing line coming back in. No recirculating pump has been located anywhere. Not at WH and there is no access to the tubs plumbing in master. no pump under sinks...

The drain valve at the bottom has been modified with a 'T' and another copper line with a ball valve running up and into the wall !!?? WHAT IS THIS FOR?
The line is cold to touch, so not an additional hot supply line. It also looks like this is original to the homes construction in 96. Theres some foam insulation on the line near where it enters the wall and goes where? why? Closing the valve at the bottom does not appear to affect water flow at any faucets or tub .... I need to get rid of this line as I'm told it is not to code. I'm stumped guys! see pics, thanks Mark

thanks

 

[Sylvan]

It looks like an added blow down valve was added as the OEM one is not a great quality and a ball valve allows for easier access.

 

[Sponsor]

 

[Reach4]

I suspect the soft copper pipe is the return for the recirculation.

Then why does it not run warm? Recirculation is not working. Maybe there is a pump that is off, or it is a gravity system, but the check valve is too tight to allow gravity-driven return flow.