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The last 8 posts

Thursday, June 26th 2008, 3:48am

by Wet_Boots

Feel free to keep overthinking this, but the fact that professionals use master valves for feeding poly mainlines should be sufficient. A throttled-down flow control valve closes faster, because the internal assembly is nearer to its closed position, and has less distance to travel.

Wednesday, June 25th 2008, 10:27am

by Aegwyn11 (Guest)

Okay, so I think I understand what flow control is, but I don't see how it helps me avoid constant pressure from being present in the connection pipe. Lets say the system looks like

PVB -------> Manifold --> Valves ------>Sprinklers
\
\----> Master Valve ----------(Poly Pipe to other side of house)-------->Valves --------> Sprinklers

So, I'm unclear how flow control could help me avoid constant pressure in the long poly pipe. Once the valves on the other side of the house close, flow control on the master valve would not matter as there is nowhere for the pressure to go (closed system at that point). I don't see how flow control would help on the secondary valves either....if they close at the same time as the master valve, there is no time for the pressure in the long poly pipe to bleed out and it becomes a closed, pressurized system again.

Wednesday, June 25th 2008, 12:27am

by HooKooDooKu

None of the valves I already purchased have flow control. So you're saying that the 'master' valve I get for this needs to have flow control? Do I need to send the other valves back and get ones that have flow control? I guess I don't really understand how flow control works....I thought it was kind of like pressure regulation.


Flow control and pressure regulators both work on the same principle: create an adjustable restriction in the water flow to reduce the water pressure. In the case of the regulator, there are springs and things that continuously widen and narrow the restriction to keep the water on the output side at a constant pressure. Flow control, on the other hand, is a fixed restriction (you manually adjust the restriction by turning a screw). So as the incomming pressure changes so will the output pressure.

Tuesday, June 24th 2008, 2:48pm

by Aegwyn11 (Guest)

None of the valves I already purchased have flow control. So you're saying that the 'master' valve I get for this needs to have flow control? Do I need to send the other valves back and get ones that have flow control? I guess I don't really understand how flow control works....I thought it was kind of like pressure regulation.

Tuesday, June 24th 2008, 2:41pm

by Wet_Boots

The master valve will have a flow control that you will throttle down, and that makes it close more quickly.

Tuesday, June 24th 2008, 11:02am

by Aegwyn11 (Guest)

I had thought about this, but was unclear if it was feasible with my controller. I got a Toro TMC-212 controller. Will I be able to set it so that for zones 4-6, the master valve opens/closes a few seconds before the actual zone valves? Otherwise, if the master valve and actual zone valves close at the same time, won't that leave pressure in the pipe going from master valve to zone valves (no way for pressure to escape)? Assuming this is possible, how many seconds would be good practice for this type of setup?

Tuesday, June 24th 2008, 10:12am

by Wet_Boots

Upstream of all the valves, you can install a master valve. That way, the poly pipe is never under continuous pressure, and is not an issue.

Monday, June 23rd 2008, 3:25pm

by Aegwyn11 (Guest)

Poly Pipe to Remote Valves

Currently putting in a sprinkler system and I'm a little worried. I've got two sets of valves...three close to the water meter and three on the other side of the house. The Toro plans called for SCH40 PVC to run from the supply to the remote valve manifold, but when I asked them if I could use poly, they said it would be fine if local codes permitted it. I already ran the poly pipe when I had the vib. plow this weekend, but I'm still nervous about it.

My static pressure is 75 PSI and it only drops to 72 PSI with the closest faucet to the water meter wide open. I did my best to measure the flow at 23 GPM. Will poly pipe before the valves really be okay? I really don't want to have to dig ANOTHER 180 ft of trench to bury PVC if I don't have to. What do you guys think?

Also, do I need to use teflon tape on MPT/FPT connections?