Originally Posted by
Gregg Austensen
So having water discharge is not always an issue? The house had 90psi and a constant drip at the discharge along with a very green plant. If the valve is set lower than this (90psi) then it will discharge? I would think that this constant discharge would not be normal. Also there was an old T&P on top of the tank. Any thoughts?
If the pressure was at 90 psi, you want it to drip continuously, because 90 psi is too high.
What is needed, then, is a pressure regulator valve to reduce the pressure to less than 80 psi.
Then, because there is a pressure regular installed, making the system basically a closed system, you will want to install an expansion tank to take up the thermal expansion.
Typically, an expansion tank is installed right at the water heater on the cold water inlet. As the water heats up, the increased water pressure causes water to back up toward its source (all valves are closed, so the water cannot flow anywhere to reduce the pressure). Being as water is a liquid, the pressure is basically the same throughout the entire system and you need to have a place where the excess pressure (from the thermally expanding water) to go, and that is where the expansion tank comes in. There is a bladder in the tank with pressurized air on the top of it and the water is pressing on the bottom of it, water is incompressible and air is not, so the air compresses even more, taking up the expanding water, creating 'more room' in the water system, thereby reducing the pressure in the water system.
I forgot who here had that problem, but they installed an expansion tank and their problem went away. Because that is what those expansion tanks are for.
I *would not* leave the pressure relief valve in the system knowing the pressure is too high, I would (my house - install an expansion tank) (house I was inspecting - recommend an expansion tank be installed).