Bob it dosent do anything that your tand p does at the water heater does. Im assuming you didnt plug off your tand p on the water heater? You do understand the pressure inside a water pipe at the water heater is the same as at a kitchen sink or anywhere in the system right? the only diferance being the t and p at waterheater would blow if the pressure or the temp got high one at the front of house wouldnt get affected by tempurature .
if you need a redundant pressure relief valve or dont have a t and p at water heater concider putting a relief valve at another area but dont plug one off at w/h unless you know what you are doing
Thanks Jeff and Reach.
You both have helped me so much in the past. So I take your comments with extra care.
I do have a 150 psi T&P on my personal WH, It never crossed my mind to plug my temp pressure relief valve. So no worries there.
The main PRV outside feeds multiple units within one shared building it feeds. I don't have control over everyone else's T&P valves. I assume they all work. However, putting a relief valve next to the PRV seemed like good insurance so that my water heater's T&P valve was not doing all the work (reliving pressure) for the entire building ( assuming their T&P vales did not work, which I assume they do work)
Based on this Pressure regulator valve and pressure relief valve setup, the water pressure would be relieved outside where the main 2" line comes into the building. This would be cold water, outside, next to a drain, next to the building's shutoff. All this is an economical backup to the PRV... Which is currently failing.
I am no plumber but this all seems like a good 35$ insurance plan, even if it was to just avoid a mess inside? Right?
I hate going against your help and all your years of insight, but after reading and discussing with others and you guys, the pros do seem to out weight the cons in this specific situation. Keep in mind this is how all the other 30 buildings are set up like this. Must be some rhyme or reason for it.
Thanks so much for your thoughts. If you have any other cons other than it being undesirable, and redundant to the home's T&P valve, I am going to take note and discuss it with my plumber further.