My local code calls for double check backflow, and that's pretty much only requirement for sprinkler system. The water service line, from the meter (5/8"), is the copper yoke. 1" PE SIDR 7 connects to the copper yoke and runs about 15" into crawlspace (undert the footing into the crawl). Once in the crawl it converts to 3/4" PEX and goes to the house manifold - this is pretty standard here as I have seen all newer houses have this PE > PEX pipe.
I will dig right after the meter to tap into the service. I need to put in a shutoff ball valve and two drain valves (one right after the shutoff, another after the double check).
The questions are where to tap in, and what are proper nipples and fittings to use. As there is more that 2 ft to dig, I want to do it right in the first place.
1. Sould I tap into the 1" PE or the copper segment right before the copper/PE junction?
2. If I tap into copper, in connecting the tees/valves can I mix PVC and brass? I know it is bad to screw a brass MIP to PVC FIP but the other way around is acceptable. So the plan is:
Cut the copper and slip on a brass compress T (3/4x3/4x1 FIP outlet), outlet points up. Screw a SCH 80 PVC nipple to the T outlet. Screw the shutoff valve (1" FIP) to nipple. Another sch 80 nipple onto valve, then a brass tee (1x1x1/2 outlet). The 1/2" outlet branches to a 1/2" PVC nipple and to a 1/2 brass valve (the first drain). A third 1" sch 80 nipple continues up to near ground level and Ell and another PVC nipple, to the brass double check. I am trying to use brass valves but create lots of PVC/brass threading together. Is this OK? Or I may be better off use sch 80 pvc valves and solvent weld everything together?
I have seen other people using galvanized nipple between all the brass valves and fittings but I know it should not be this way due to electrolysis.
3. If I tap into 1" PE pipe, it seems I have to use barb x barb x FIP Tee to start. I cannot find another better T for 1" PE. Using insert T on the service main makes me feel uneasy. Any comments?
4. Lastly, I have 7 zones, 3 on the other side of the house. Is it better to put all 7 valves near the meter and run 3 long PE pipes (100' - 150'), or run one 1" PE to the other side and put the 3 valves there?