Log in

View Full Version : How to change a PRV?


Ghanouni
Sep 7, 2008, 01:31 PM
My PRESSURE CONTROL VALVE on my home water line no longer controls the water pressure and the pressure is up to 150PSI when measured. It appears that the PCR is shot. I discovered that because the water heater started leaking through pressure relief valve. I chanaged the PRV twice and the leaks continues... I understand that I need to install an expansion tank and intend to do it. Please answer the following two questions:
1- Is the PCR bad?
2- Is it easy to replace it? I have copper pluming. Thanks

massplumber2008
Sep 7, 2008, 03:23 PM
The temperature and pressure relief valve should indeed have blown off as it is designed to blow off at 210F or 150 PSI.. so good that valve is doing its job.

With that in mind, certainly sounds like the pressure regulator is shot...

Most pressure regulators have a union on one side. If this is case with your regulator then you should only need to shut the water main off at the water meter, open some faucets in the house and then release the union fitting by using two wrenches or pliers and then simply remove the pressure regulator by loosening valve counterclockwise. Then apply teflon tape 6-7 wraps clockwise and install a new pressure regulator, etc...

If your pressure regulator doesn't have a union then you will need to shut the water off to the house as above and you will need to cut into the copper tubing say 6 inches PAST the pressure regulator (i.e. on the reduced pressure side) and then remove the old regulator using two wrenches as above and reinstall new one using teflon tape, etc. again as posted above. Then you will need a SHARKBITE type copper tubing coupling (see picture below)... this will simply push onto one side of the copper tubing and then you will push the other end of the copper tubing deep into the fitting and you will be finished installing the unit(available at all home supply stores today). Using this fitting will keep you from having to solder any pipes!

Then you want close any faucets you opened, then open the water meter shutoff, and then open the nearest laundry faucet or outside faucet to purge any sediment/air from the system that was disturbed via working on the main line. Then you will open all faucets and fiunish purging air from lines.

Finally, you need to take a reading on the pressure and see what pressure the regulator is set too... anywhere between 45 and 60 psi is acceptable range. Anything above or below will require you to make adjustments to the knob on top of unit to finish this job.

Always a good idea to have an expansion tank... come back when time to install this and we'll be glad to walk you through.

Let us know if you have any questions...

MARK

afaroo
Sep 7, 2008, 05:50 PM
I would like the following just for info as mark says you need to check the pressure you would need a water pressure gauge see the images below, good luck.

John

ballengerb1
Sep 7, 2008, 06:01 PM
Got losts of terms here, PRV and PCR. You are talking about a pressure reducing valve (PRV) but you say you replaced it twice? I'm confused. Did you replace it twice or adjust it twice?

massplumber2008
Sep 7, 2008, 07:08 PM
Here's how I read it Bob...

Ghanouni wants to change his PRV (pressure relief valve) because the pressure control valve is shot. He appears to have changed the PRV twice and I can't be 100% sure but he seems to be calling the pressure control valve a PCR... Of course, to complicate things it's actually a pressure regulator (PR) or a pressure reducing valve (PRV) as posted by John... which really complicates things because there is just too many PTMMGHT (Ps that make me go hmmm, too)!

I will only barely mention the fact that you added to fun here by calling a pressure relief valve a PRT...and ghanouni never even mentioned a PRT... :D

Let us know what's up Ghanouni... ;)


MARK

KISS
Sep 7, 2008, 09:29 PM
The thingy on the water heater will leak if the thingy (1) on the water main is broken or adjusted improperly. The thingy (2) on the water heater may or may not have to be replaced even if it leaked.

An expansion tank should only be necessary if someone installed yet another thingy (Check valve, backflow preventer) on the main.

It should all be clear once the technical terms are defined.

1. Something that regulates pressure and is usually adjustable
2. A pressure and temperature relief valve. Failures are USUALLY non-destructive.

ballengerb1
Sep 8, 2008, 07:44 AM
Mark, if I'm going to quote a guy I guess I should do it right, made the correction. I don't think we will get anywhere until Ghanouni returns to straighten this out but I think he is confusing the names and functions of the PRV and the P&T.