proper water pressure

Old 06-24-18, 08:11 AM
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proper water pressure

what is the proper water pressure for a smaller residential home?

here are my particulars
public water with 1" copper supply into 3/4" for house
smaller one story home with one bathroom
oil heat with amtrol unit for hot water

there is a watts pressure regulator 25-75 range which i try to set at about 75 but find
the pressure is always varying slightly, up to about low 80's

my additional concern is that when the boiler is circulating the hot water into the amtrol unit the pressure spikes to 120
i know this is rather high, i thought the boiler would be isolated from the water supply?

Old 06-24-18, 11:54 AM
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I usually set pressure to something between 60 and 80 psi. Everyone loves higher pressure but it puts a bit more strain on the pipes and fixtures. It's not a big deal for newer homes but for an older home it can make a difference though if plumbing is aging all a lower pressure does is forestall the eventual leaks.
Old 06-24-18, 02:41 PM
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When using a PRV, you also need to have a functioning pressure bladder tank in the house too. Typically it's installed on the cold water line near the water heater.

The purpose of it is to handle the pressure increases as the water heater heats cold water in the system. (water expands as it gets hot) It sounds like you're missing one - this will also help the varying pressure through your PRV.
Old 06-24-18, 08:35 PM
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there are two in the system
one dedicated to the boiler, and a smaller one installed on the cold water line near the water heater as you said.

both of those bladder tanks were installed about 12 years ago, is it possible they could be faulty?
any way to check if they are functioning properly?
do these typically have a life expectancy?

the spike to 120psi worries me
Old 06-25-18, 02:54 AM
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Yes, quite likely they have failed. All they are is a rubber bladder inside the tank. Air compresses, water doesn' they are acting as giant water hammer reducers basically. They absorb spikes or slight pressure increases by compressing the air in the bladder, instead of possibly tripping a relief valve of some sort. They should be marked with the pressure they should be filled to with an air source. I believe you need to cut off water and drain pressure off, then set the air tank pressure? And it probably depends on what your standard supply pressure is. You wouldn't want the tank set at 10 when you have 70 psi water pressure. Check to make sure...heck, filling it to 70 with no water pressure could burst the bladder for all I know.

Simple test is depress the schrader valve that you put the air in. If water squirts's bad. That I'm sure of.

The one on the boiler probably has a different procedure. The other guys would know, or a simple search for "setting expansion tank pressure for water heater" or "boiler" should turn up something.

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