SPRINKLER TALK FORUM - You Got Questions, We've Got Answers

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?

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?

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.

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.