Installation of the flow meter with 1" schedule 80 PVC


#1

My irrigation system uses 1" schedule 80 PVC at the backflow preventer instead of the usual schedule 40. Should I still use the Orbit 1" PVC coupler model 38676? Will it fit? And I think that the Orbit coupler is not rated for as high a pressure as schedule 80, but I’m assuming for an irrigation system, that shouldn’t matter because I probably will never reach the pressures where schedule 80 is required to begin with. Is that a correct assumption? thanks


#2

The Orbit coupling will work fine on Schedule 80. It has the identical outside diameter as the Schedule 40. Please be sure to check the pressure prior to installation to make sure you do not exceed the 150psi max pressure.

Your irrigation system will appreciate running at 95 to 100 psi anyways.


#3

Great, thanks for the reply. But how would I go about measuring the pressure to ensure it doesn’t exceed 150psi? Thanks


#4

There are a few ways to do this.

  1. Check with a water pressure guage on any hose bib that may be on the same pressurized line.

  2. Remove pressure guage from it’s hose bib adapter and make and adapter to go from the 1/4 MPT pipe thread down to a thread that matches your bleeder screw. Remove the bleeder screw from your valve and attach the pressure guage while reading the where the needle goes to.

  3. You can purchase a sprinkler head adapter to match either a Rainbird/Hunter thread or a Toro thread and you can screw your pressure guage straight into that. You will need to turn down the screw on each of the other heads on the same zone in order to get an accurate reading.

I use either of the 3 tips or just call the water purveyor for the area that I am working in and find out what the static pressure is for that area. When this is the case, I must note what time of the day it is since water pressure is 20 to 30% greater during permitted irrigation times.

If you are on a well and pump system, your water will be more constant as the pump should kick on when the sprinklers are running.