Meter Install with Master Valve Questions


#1

I would like to install a master valve on the left side above the shut off valve and the flow meter on the right side above the union. Any assistance out there on the best way to go about it and which fittings and couplers I may need?

Thanks.


#2

@SDR - certainly possible as you’ll need to raise the anti-siphon device up to have enough room before the flow meter. Very similar to this post ->

I’d use the male push on adapters mentioned in the referenced post in the 90 degree elbow and union with PVC Lock connectors to connect the PVC pipe to the flow meter.

I’m not sure if there are female connections on the inflow side at the valve and anti-siphon device to where one can do the same type of construction on the inflow side. Additionally, it was suggested to put a union on the left side so the entire upper unit could be easily removed.


#3

Thank you for your response! Best I can tell, all of the current connections utilize male nipples. The second union on the left does seem like a good idea.


#4

This project is a little more involved than I initially thought and I have some questions.

I believe I need to replace the backflow preventer in the picture with a reduced pressure backflow preventer. In addition, with my 95 psi incoming pressure, I will be adding a separate pressure reducer along with the flow meter and master valve.

My thinking is put the pressure reducer first, then the reduced pressure backflow preventer followed by the flowmeter and lastly the master control valve. Is this the proper order for these components?

Lastly, as shown in the picture, there is only 7 inches between the two risers coming out of the ground. Would it be ok to plumb the components in a “V” configuration (with the end of the V floating in air) or do I need to dig up the downstream riser and move it?


#5

Wow, 95psi!!! Do you not have a pressure reducer prior to this on the main line coming into the house?

What I would do…if the backflow assembly is in good working order, I would leave it alone. You need to extend the height of the system anyway in order to install the flow meter, so on the incoming side below the ball valve, I would just install a pressure reducing valve.

Zurn/Wilkins Pressure Reducing Valve

Your other option is to ditch the existing backlow, and go with a pressure reducing backflow device that will encompass both needs in one unit, but at that point, you are looking at a unit that is almost 20" long and will require significant repiping to fit.


#6

I do have a pressure reducer at the house.

I am under the impression that to properly utilize the existing type of backflow preventer, it needs to be higher than the highest sprinkler head in the system. As I am unable to practically place it at the high point, these reduced pressure backflow preventer’s apparently will work in this scenario. Am I correct in these assumptions?

Do you believe that I can re-pipe utilizing the V shape I mentioned, or will I need to dig up and move the downstream riser?


#7

So your current installation doesn’t have the backflow as the highest point in the system?

You are correct that the pressure reducing backflows can work at any installed height. And yes, you can install using the “V” to get the width needed, but that could cause some issues with trying to get the flow meter installed.


#8

Thanks for hanging in there with me.

My thought was to place the pressure reducer (with Y strainer) vertically going up 10 or 12 inches, then go horizontally (about 16 inches) with the reduce pressure backflow preventer and if using the V configuration come back and down to the existing downstream riser. This way I would have approximately 16 inches horizontally and 10 or 12 inches vertically to place the flowmeter and master valve.

There would be nothing supporting the piping at the junction of the V. Would this be okay?


#9

You don’t need both a pressure reducer and a pressure reducing backflow device. The pressure reducing backflow device manages both functions. If going the PR backflow route, there is going to be a lot of weight hanging up in the air. If you have to this route, I would pipe the supply side with galvanized material to keep some structural rigidity.

Back to my last question, is your current installation of the backflow not at the highest point of the system? Do you have a large hill on your property? Simply adding a pressure reducer would be a much easier option if the current installation is functioning properly.


#10

Thanks for the reply. As I mentioned up thread the current backflow preventer is not at the highest point. How it was installed at a spot way lower than the highest point escapes me (other than it was at a convenient spot close to the meter). It would take at least 100 feet of pipe to place it at the highest point plus the current one is at least 25 years old. I figured a new RP backflow preventer is the faster, cheaper way to go.

I understand that the RP backflow preventer drops the pressure approximately 15 to 25 pounds (I don’t believe they are adjustable). At 95 pounds static, I thought it needed to be reduced more so I thought I would add the pressure reducer.

Galvanized is a good idea to help support the weight, although I suppose I could install a post to support the hanging end of the V… Of course it would be a cleaner install to dig up the downstream riser and move it, but digging and roots are not my favorite thing.