Originally Posted by
John Goodin
Sure Dan. Pressure reducing valves create a closed system where water can not flow back past the PRV toward the meter or main water supply. When the water is actively heated it expands creating more pressure in the system. The expansion tank installed on the cold water line of near the water heater looks similar to a small propane tank and contains an air bladder. As the hot water expands the expansion tank helps alleviate the increased pressure. The same goes for tankless water heaters.
As Ron said above he has had his house 20+ years with no issues and for many people that is probably the case. What I was referring to is simply the IRC and plumbing code which is typically written towards worst case scenarios. Expansion tanks cost about fifty bucks which is a relatively minor homeowner cost and are simple to install if you have a shut off valve on your cold water inlet a few feet before your water heater.
John
This is definitely different than on a well system.
There must have been some other changes to the codes, as the isolation valve for the cold water supply "used" to have be installed at the tank. Additionally, inlet and outlet check valves had to be installed at the water heater inlet and outlet. Water can only flow one way through my water heater, it cannot impulse back down the cold supply line. Maybe all new water heaters have this built in??
There is a "bladder" tank installed on well systems, but it's not for the same purpose. Mine is a 35 gallon tank that is precharged to the "cut in" pressure of the well pump, 32psi. The "cut out" for the well pump is set at 55psi. The "bladder tank", or "WellTrol" tank is there to reduce the duty cycles on the pump. A well pump is not a solid system.
Not sure I agree with calling a home plumbing supply system "closed". I understand what they mean, but the system is not closed. Every time a faucet opens pressure is changed. Semantics, I guess.
It's always different to see how things are done in different areas of the country.
To the OP
Stephen, no 60-70 psi is not too low for a water saver to work properly.
"The first thing you need to know, will likely be the last thing you learn." (Unknown)