PRV question


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Old 12-04-10, 02:36 PM
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PRV question

I'm thinking my PRV is toast....

Here is what is happening. I noticed yesterday my hot water tank is leaking a very small amount of water I believe from the pressure relief valve but I can't say 100% for sure as the drain goes in behind in a corner. It doesn't appear to be a steady/audible stream though which I would expect if the tank was gone. Does this sound right?

I tried reducing the house pressure at the valve. I turned it 4 full turns counter clockwise and there is no noticeable drop in pressure. I don't have a pressure tester to know for sure. Should I go further? Will the screw come right out and leak water?

I do have one more issue if the PRV is bad. When the city upgraded to metered water they soldered a meter right above the prv and now there is only about 1/3 of an inch of copper between the prv and shutoff for the house. Could I just install a new PRV above the old one and the water meter without removing the old PRV? Otherwise I think I'll have to call the city to shut off the water to the house...

Thanks!
 
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Old 12-04-10, 03:45 PM
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I'm having trouble visualizing your installation, can you post a picture?

Yes, the adjusting screw will come out of the PRV if you unscrew it far enough. Water shouldn't come out the hole but if you have a ruptured diaphragm it will.

You really need a pressure gauge to adjust the PRV. Get one at the big box mega-mart homecenter with a resettable highest reading hand, about $10. US.
 
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Old 12-04-10, 03:59 PM
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Originally Posted by tha_dub View Post
I'm thinking my PRV is toast....

Here is what is happening. I noticed yesterday my hot water tank is leaking a very small amount of water I believe from the pressure relief valve but I can't say 100% for sure as the drain goes in behind in a corner. It doesn't appear to be a steady/audible stream though which I would expect if the tank was gone. Does this sound right?

I tried reducing the house pressure at the valve. I turned it 4 full turns counter clockwise and there is no noticeable drop in pressure. I don't have a pressure tester to know for sure. Should I go further? Will the screw come right out and leak water?

I do have one more issue if the PRV is bad. When the city upgraded to metered water they soldered a meter right above the prv and now there is only about 1/3 of an inch of copper between the prv and shutoff for the house. Could I just install a new PRV above the old one and the water meter without removing the old PRV? Otherwise I think I'll have to call the city to shut off the water to the house...

Thanks!
Most of the time the T+P only lets water out when the pressure is too high or the temperature is too high.

Do you have a expansion tank on your water heater? with a PRV in your system you need one. To check the PRV right you need a gauge.
You also need a gauge to set a new one.

You need to put a gauge on the nearest hose bib to you incomming water and check the water pressure, then you have to gauge it after the PRV, if you are getting near 80lb the PRV is not working, you can keep adujsting and see if the pressure drops (you have to bleed the pressure off ever time you do this), if you are not getting any response you need a new PRV.

I would not leave a defective PRV in your system :NO NO NO:
 
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Old 12-04-10, 04:32 PM
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I think I understand the question, but why can't you rebuild the existing PRV? Even if you have to buy a new PRV, you could cannibalize it and repair the one you have and test it properly.
 
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Old 12-04-10, 04:38 PM
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Yes you can but it will look like a......ss

Mike NJ
 
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Old 12-04-10, 05:29 PM
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prv | Flickr - Photo Sharing!


There is the pic. I'm going to pickup a pressure guage tomorrow to find out for sure.

I'm fine cutting the copper at the top it's down below between the shutoff and the prv. I don't think I'll be able to solder that close to the shutoff without some real risk. Any ideas? I'm open to rebuilding the old prv if that is an option but I'm not sure how.

Thanks for all the replies!
 
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Old 12-04-10, 05:57 PM
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The prv gets turned clockwise to reduce pressure. And if bad you have unions just replace, just put a new one in. The other is a check valve.
 
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Old 12-04-10, 06:04 PM
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Are you sure you turn clockwise to reduce pressure? I found a few links on the web that say the opposite.

How to Adjust a Pressure Reducing Valve | eHow.com

Can anyone else confirm this?

Thanks!
 
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Old 12-04-10, 06:12 PM
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Old 12-05-10, 02:57 AM
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Make sure you test the pressure after the PRV. If you have a check valve you need some type of thermal expansion devise. If the pressure tests at 65 psi or less you need to change the T&P they can go bad on there own.
 
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Old 12-05-10, 07:44 PM
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Okay so I tested the water pressure and I'm now sure my PRV is bad.

It buried the needle on the gauge which goes to 100 psi. Just to be sure I checked my neighbors whose came out at 75 psi.

Per the picture if I cut at the top U can I unscrew the whole deal from the fitting at the bottom (I assume there is nothing special about it and it unscrews counterclockwise)? I'm a little concerned about cracking the joint at the shutoff and then I have real problems. I can't seem to locate the city shutoff which would make my life a heck of a lot easier and I'm a worried the last owner paved over it when they expanded the driveway.


The PRV and the coupling look like they've been together an awful long time. Can I use anything on it to get it un-seized before I really crank on it? Like WD 40 or something like that?


THANKS!!!!!!!!!!!!!!
Thanks!
 
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Old 12-06-10, 05:00 AM
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The pix helps. As lawrosa said, you have unions. Loosen them and remove the PRV. Remove the stubs on the PRV and install on the new one and put it place. Job done. You don't have to do any cutting or soldering.
 
 

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