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Starting Member


Monday, March 21st 2011, 2:46pm

1" valve on 1 1/4" supply line

I have a 4-zone indexing valve on my sprinker system that has 1 1/4" PVC supply lines exiting the bottom of the valve for each zone. The system was already installed when I bought the house 17 years ago so I don't know if the supply lines transition to 1" in ground or not. The indexing valve is in pretty bad shape. I have to constantly disassemble and clean it to keep it working and now the iron pipe from the pump to the indexing valve is rusting out and leaking badly at the threads. So since I'm going to be tearing it all down anyway, I figured I would convert over to automatic inline electronic valves. The problem is, the only valves I can readily find are 1". Would I be creating flow problems if I use a PVC adapter to put the 1" valve in line on the 1 1/4" PVC supply lines for each zone?


Supreme Member

Posts: 493

Location: Seattle


Monday, March 21st 2011, 9:23pm

That's hard to say.
It all depends on the design of the system and how large it is .

Since you have a pump system you can't really get a GPM per zone , If you could you could determine if 1" supply is enough..
More then likely it will do fine, though that's just guessing.

They don't make 1.25 valves . The next one up are 1.5- you could buy 1.5's and bushing back down to 1.25. But those are commercial grade valves and are expensive.


Supreme Member

Posts: 5,307

Location: Metro NYC


Thursday, March 24th 2011, 7:45am

Unless the pump is pushing way more than 20 gallons per minute, you do fine with one-inch vslves.

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