Supply plumbed into drain has me scratching my head!

[dedson69]

Hello. I'm new here and was hoping someone could answer my question. As you can see in the picture, the cold water line is connected to the drain pipe for the pressure relief valve. I'm replacing the water heater and I can't figure out why it would be plumbed this way. Thanks in advance if you can answer.

 

[Twowaxhack]

Ones a T&p and the one near the walling just pressure most likely.

it may have been used to control thermal expansion.

It probably doesn’t operate.

 

[RS]

I agree, to the left of where the pipes join it looks like another relief valve, and they are just piped together down to a drain.

 

[dedson69]

Ones a T&p and the one near the walling just pressure most likely.

it may have been used to control thermal expansion.

It probably doesn’t operate.

Thanks. So I could eliminate it altogether? The new water heater's T&P is on the side of the tank so I was going to tie into the drain lower down the pipe.
Or not connect it at all. The water heater is in the garage so I was going to just run the pipe straight down to the pan.

 

[dedson69]

I agree, to the left of where the pipes join it looks like another relief valve, and they are just piped together down to a drain.

Thanks. I appreciate it. I was wondering what that fitting was. I assumed it would only let the water flow to the drain if needed.

 

[cdestuck]

When you do this, get rid of those gate valves and add ball valves.

 

[dedson69]

Another thing that's got me puzzled is the U shaped 1/2" pipe with the valve that tees off right before the water heater shut off valve. It's turned off and if I open it I hear water flowing but I have no idea where it goes! There are no fixtures in the house that aren't getting water and it's always been off...

 

[Twowaxhack]

Thanks. So I could eliminate it altogether? The new water heater's T&P is on the side of the tank so I was going to tie into the drain lower down the pipe.
Or not connect it at all. The water heater is in the garage so I was going to just run the pipe straight down to the pan.

You should pipe the relief valve outside. If it ever pops off due to temperature it dumps a lot of water.