What's wrong with this setup?

[AirOp]

1, the added cold water shutoff valve is leaking, so we'll get the company back out under warranty... but I think there is more wrong.

Good things: expansion tank installed, straps installed
done quick

bad things:

I don't think those are dielectric connectors...
they say they can connect to iron pipe, and I believe are brass touching the galvanized nipple, but... errr, i've seen those rust.

The pressure relief drain has lots of kinks and bends.. and goes down the floor.. I don't see where it goes, and I think this is wrong somehow. this is how the old one was installed but I believe it's not ok... and i believe it's brass to it. I would expect a steel to cpvc and then cpvc to a few inches off the floor.

 

[AirOp]

(the tape on the sharkbite fitting is cringe but it's my family member attempting to slow the leak)

 

[breplum]

Look at the instructions, it should typically show that there is supposed to be a drip tee right at the gas control valve to absolutely protect the valve.
The tank nipples are typically shipped with the WH and they ARE dielectric with plastic liner inside that you just can't see.
T and P, by code, must exit to a exterior location and terminate not less than six nor greater than...16 . above the ground, if I recall correctly.
Code requires that single wall pipe for the flue vent only be used in conditioned spaces. In unconditioned space, all pipe must be double wall.

 

[AirOp]

T and P, is that thermal and pressure?

so the nipples are already dielectric, so it's fine, or the connectors are dielectric, but not the type i am familiar with?

The gas stuff I don't know much about, I installed gas ranges which didn't have as many problems.

I don't know exactly the definition of conditioned spaces, but this used to be a porch but is insulated and accessible from the inside. washing machine and dryer are also in the room

 

[Stout Mechanical]

It looks like a kindergartner installed it, here you would fail for having the valve between the expansion tank and water heater in addition to no drip leg

 

[breplum]

"Conditioned space" means that it is part of the interior with heating, so not cold. The issue is that cold single wall sheet metal vents cause the vent to not properly flow and backdraft or spillage of carbon monoxide can result.