Question
I have a 6 zone residential system with HydroRain valves about 30 years old and a bit beaten up (a couple of the flow control knobs are broken off). Zones sometimes fail to turn off and anyways, I want to move the valve manifold because of a patio reorganization so in anticipation of this a bought a brand new 6-way manifold complete with valves and solenoids from a local supplier about a year and a half ago (it takes me a while to get around to stuff). It has 1" valve connectors, as does pretty much everything I have seen on the web. Imagine my surprise when I finally dug up my old manifold and found that the in and out lines to the HydroRain valves are 1 1/4". Of course I can use reducers on the input and output sides but since flow presumably goes as area this would represent a 33% constriction over what I have now. Should I be worried that my furthest heads will lose pressure, and of so is there ANYTHING I can do about it short of redoing the entire system? (That is, does anyone sell 1 1/4" valves?) I have about a 1.25 acre lot and the furthest zone has about 4 rainbird maxipaw popups and 5 raised 1/2" impact heads on it. Pressure at the furthest head isn't an issue right now, although it does have a bit less oomph than the heads near the house. Most of the risers are 3/4".

Sorry for the book but I'm trying to convey enough information. Should I stop worrying and just install the new manifold? I'm trenching out the whole new manifold location ahead of time so I can switch things over in a day, but the problem is that at this time of year, once I break the lines I'm in trouble pretty quick if it doesn't work! I'm placing the new manifold about 20 feet from the old one (closer to the source) planning to just connect the outputs into the existing zone lines.

Thanks in advance for any advice.

Answer
Maxipaw sprinklers are usually fairly low flow, so if you have only 4 or so per valve, I think the 1" should be able to handle it.  If you do encounter problems, you may consider just replacing the runs of pipe between the manifold and the first sprinkler on each station.