Installing a pressure-reducing valve

secutanudu

I want to install a pressure-reducing valve on 1" copper. This is the feed for my parents' lawn sprinkler system. They have about 180PSI (bumped down to 50 for the rest of the house). The feed for the sprinkler is before the regulator, and we use a sprinkler valve outside with a regulator on it to drop the pressure to about 70psi for the sprinkler system. The problem is when the system turns on and off, all the valves really get jostled violently. I want to put a regulator on the copper inside, and I have a few questions.


1. What valve would be recommended? Most watts regulators I see can go from 25-75 PSI. If I want to drop it to 75PSI, is it ok to run the thing at its upper end constantly, or should I find one with a higher range?

2. The one I was looking at comes with unions on both ends. I'm not that experienced with cutting pipe to put new devices inline. How do I know how much pipe to cut out of the line?

Thanks.

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Andrew

secutanudu

Any ideas on this?

Thanks.

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Andrew

bob22

1. Go to a plumbing supply or look up on Watts site for a regulator that will handle the incoming pressure. Don't buy one whose maximum pressure is less than what you have; it will fail and a lot of water may show up.
2. Usually, a 1/2" fitting needs 1/2" inch of pipe inside of the joint; I'd assume a 1" fitting needs about 1" of pipe inside the joint. If the overall length of your PRV is say 10" (measuring from the outside edge of the assembled unit's solder joints) then cut out 8" from your existing pipe. You will need 1" on each end for your joints, giving you 10".
To check this, cut the pipe first, slide your solder joint over a pipe end, mark the edge with a pencil, pull it out, measure from your pencil line to the edge of your cut pipe; this will tell you how much of your tubing will need to go into the solder joint. Measure and cut the balance of the original tubing accordingly.

secutanudu

Thanks Bob. Any recommendations as to whether to get the solder unions on the ends or the threaded? I am not very experienced at soldering, but I can usually do it ok. I assume if I get the threaded ones, I need to solder a male adapter on each end of the cutout.

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Andrew

Alan

We always use the threaded ends, because we normally use them for a transition point from pvc (outside material) to whatever material we are using inside the house.

You could go either way, but HOPEFULLY if you got the sweat unions you wouldn't have to unsweat them later....

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Journeyman Plumber

secutanudu

Ok - here's a pic of the situation, and some questions.

I have a boiler drain inside so I can drain the pipes. Can I put a pressure regulator downstream of this drain, or do regulators act as backflow preventors, which would render my drain useless.

The problem is I don't have enough room between the sprinkler shutoff valve and the brass tee with the boiler drain for the regulator. I am trying to do as little cutting/soldering as possible.

Also -if I decide to move the boiler drain up (downstream) so I can fit the regulator before it, can I re-use the brass tee or do I need to buy a new one? Thanks.

Also - if I need to buy new copper pipe (1") what is the appropriate type for this application (M, L, K)?

Thanks.

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Andrew

secutanudu

I just did a simple test with the new regulator - i held it under the sink and ran water into it in both directions - in both cases the water drained out the other side, which leads me to believe it does NOT act as a backflow preventor, and I can put it downstream of the drain. Does this make sense?

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Andrew

Alan

Is there some reason they wouldn't want their house pressure at 75?

Seems to me the cheapest and really the easiest way would be to eliminate that tee, and reroute the sprinkler line to tee in just downstream of the regulator, and run both at 75PSI.

To answer your question, a PRV is not a backflow device, unless for some odd reason it has an internal check. It would say somewhere in the owner's paperwork that came with it if it did.

Also the test that you performed isn't exactly accurate anyway... a lot of check valves require a certain amount of pressure to be activated. Draining water through them would not cause them to close.

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Journeyman Plumber

secutanudu

But that's all I'd be doing "backwards" through the valve anyway, draining the pipes under very low pressure.

Isn't 75PSI kind of high for a house line?

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Andrew

Alan

I don't know about your local code. 80PSI is max by UPC, so 75 PSI while a little higher than normal, isn't out of the ordinary.

we normally go right around 65, and a lot of times higher if people are real particular.

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Journeyman Plumber

secutanudu

My dad is a little concerned because a plumber told him not to go above 50. I have been bugging him to at least bump it up to 60-65 to get some better pressure in the showers.

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Andrew

secutanudu

Already had the regulator, so I went ahead and installed it. My first time actually soldering pipe for real (I had done it to practice on scrap pipe) and it worked...no leaks!

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Andrew

Scuba_Dave

Is that 180 PSI or is that a mistype?
I've had 70-80 psi at this house & the last house
There isn't any pressure reg at either house

I did learn to always shut the hose off after using it
And not to buy cheap hoses

secutanudu

Nope - not a typo. But i was wrong, it is slightly less, about 150-160. Still crazy high for domestic water.

With no regulator, through the 1" pipe we filled a 5 gallon bucket in something like 6 seconds.

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Andrew