water pressure issue

realolman

A friend of mine has a water pressure problem. I said I would ask here and have the answer shortly...



He says his boro water coming in is about 100 psi, and he has a regulator on it to take it to about  55 psi.



He says the water pressure is way too high for about  a second or two when turning something on in the house .   I told him maybe he needs two regulators in series or maybe some sort of bladder tank,  but I really don't know ... I was just guessing.



What should he do?



thanks

icesailor

Pressure Reducng Valve:

He needs to have the valve replaced. The pressure is leaking by the seat. Iether the seat is worn, the washer is bad or both. The leaking seat is allowing the street pressure to leak by and build up pressure.

adambuild

!

I second the motion!

realolman

he said he already had four plumbers there

I think he said he already had that done.  He told me he had four plumbers there who didn't know what was wrong.



That's why I asked here.



Could it be anything else?



thanks

Ron Jr._3

You're on to something

with the domestic expansion tank .



My guess is the presssure builds up when the hot water reheats .  What do they have to make hot water ?

Jean-David Beyer

Could there be an anti-backflow valve...

supplying the cold water to the hot water heater? And no expansion tank after it? If so, then heating the water would make it expand, raising the pressure.

realolman

I'll ask about the water heater

he said he's replaced it ( the regulator ) twice for a total of three...  he said one of them actually "blew up"



Could it be that the incoming pressure was too much for the rating of the regulator, and more than anyone thinks it is? 



apparently he doesn't have a gauge.

hot_rod

put a gauge on

the incoming side and after the reducer. Get a couple lazy hand gauges that record the highest pressure. Then you will see any line surges. Use a 300 lb gauge on the high side



hr

kevin_58

water pressure

If when he turns on a faucet and there is high pressure then it dies off in a couple of seconds he needs a thermal expantion tank.

Mark Eatherton

Tank flex.

Believe it or not, cylinderical tanks can and do flex when exposed to high pressure. When the pressure is relieved, they unflex, giving a quick spurt of pressure. Not good for the tank.



If they install an expansion compensator, make certain that they air the diaphragm up to the operating pressure of the system or the problem will actually get worse.



They use expansion tanks as water reservoirs for people who service growing plants in office settings. They make a GREAT pressure tank. If the diaphragm is not properly adjusted, and is under pressured, the tank will take on a whole lot of water, then when the tap is opened, and it see the drop in pressure, and the incoming water is restricted through the PRV, then the tank dumps its charge into the cold water main, giving an even BIGGER spurt than just the flexed DHW tank use to.



Water is virtually incompressible. The compression and contraction HAS to be coming from somewhere.



I once built a "squirt gun" out of a number 30 expansion tank that I kept hidden in the back of my service van to pay some employees back for a dousing that they gave me once while we were river rafting. Only problem was, my pay back to them came in the middle of the winter. I SOAKED the living bejezits out of them :-) They had to go back to their room to change clothes they were so wet.



I warned them when we were on the river not to mess with the king of pranks...



ME.

heatguy

prv

prv in most cases has check built in so pressure will tend to stack when hot water is made the expansion tank will help but as me said make sure bladder in tank is charged with correct air pressure

icesailor

Pressure/Expansion tanks:

Thiis is an old thread but,

Mark,

When using a pre-charged pressure tank, you must ALWAYS set the precharge LOWER than the water being protected. If the PRV valve is set to 60#, set the precharge to 50 or 55#. That way, it keeps the diaphrgm from slamming into the bottom of the bottom of the tank.

On well systems, you need to do this so that the pump can start and start making pressure before the water in the tank drains. This is a very common problem on private water (well) systems. On old jet pumps, if the cut in pressure is dropped  to 25# to make it a 25#/45# on, off, and you had it set as a 30#/50# set up, and don't reset the precharge pressure, it will pause.

It's like needing to change the precharge in a heating extrol tank when you raise the system pressure.

Or, that is how it works for me.

Mark Eatherton

Well tanks versus Expansion tanks....

Ice, I agree with you on the setting of the diaphragm pressure as it pertains to a well pressure tank, but if you do that with an expansion tank, the flexed diaphragm detracts from the acceptance factor of the tank, hence the reason the manufacturers want the tank air up to the same pressure as the incoming water pressure.



Here is a link to the Installation instructions.



http://www.amtrol.com/pdf/9015-087revDTXT.pdf



ME