Leaking T&P Valve

[Jeepster04]

My neighbors are having an odd issue that has me a bit stumped. I do not have the full background as I imagine they do not know. In short, I think they either noticed their water bill being too high or heard their T&P valve hissing. They had the old T&P valve replaced, still noticed it, had the water heater replaced, still noticed it, had the T&P valve replaced twice on the new water heater, still noticed it. He casually mentioned it to me and being a curious lad, I checked it out. I checked their water pressure and its only 60psi. I left the gauge on their spigot and asked them to check it early in the morning before anyone flushed a toilet, used water, etc, he said it was always 60 psi. The T&P is plumbed to drain under their crawlspace, so I would be scared to look under there.

I checked the bladder tank and it only had 48psi in it. I put 70 psi in it to get it above the city water pressure and told him to keep on eye on it. Odd thing is, I cant assume this issue has always existed and the bladder tank was just installed with the new water heater.

Any ideas? The water heater was set to the second setting out of 5 settings. They said the water is not TOO hot. When I feel of the pipe going into their crawlspace, its hot like water is constantly flowing through it.

 

[Zeke]

Another leak somewhere on the hot side? T&P needs to exit the building.

 

[manwithtools]

Sounds like they need to call the plumber back to fix the issue, whatever it is. I can't imagine that many T-P valves. and no way should that T-P drain line feel hot all the time.