TPR valve on water intake line

[Robert Huffman]

Any idea why someone would put a second TPR valve on the water intake line but put no pipe on the TPR valve that came with the water heater?

[Jerry Peck]

Photo?

It is quite possible that the relief valve on the cold water supply line is a PRV (Pressure Relief Valve), and if it is a PRV, then that is likely the thermal expansion relief valve for the water heater.

When water is heated, it expands, and the expanding water pushes back into the cold water supply line, which pushes the water in the cold water supply line back into the pipe supplying it.

Stupidity (i.e., minimum code) only requires a means to relieve that thermal expansion ... without also requiring a way to drain off any water which is released by a relief valve.

Actually, "stupidity" is just the common word we use to describe actions like that, but the better way is: "Code is the most unsafe way one is legally allowed to build", or, "Code is the least safe way one is legally allowed to build".

I like the former best: "Code is the most unsafe way one is legally allowed to build."

Anything better than code is 'less unsafe'.

Never, ever, say that a building is "safe" - ALL building are "unsafe", some are "less unsafe" than others, but all are "unsafe".

If one thinks that a building is "safe", please provide an example of what you consider to be a "safe" building ... and I'm guessing that I am not the only person here who can respond with reasons why that building is "unsafe".

Even an M1A1 Abrams Main Battle Tank would not make a "safe" building ... if you could even get an M1A1 Abrams main battle tank to use as a building (which is highly unlikely).