Ok, I have read almost every post in the archives but would still like clarification on the system I am attempting to install (brand new).

I have 6 zones layed out. One zone requires 9.6GPM, 4 require 12.6 GPM and the last requires 13.1 GPM. Now these requirements are based on the labels on the sprinkler heads; most of which are pop-ups, 3 of them (1 in each of 3 of the zones) are popup impact heads. The pop-ups state 25PSI and the impac state 40-60PSI.

All of the piping is 1" CL200 PVC pipe, with 1/2 risers (except the 3 impacts which are 3/4" risers).

So, I am going to be using my old well (since the house is now on city water) and it will be dedicated to this irrigation project. It is a 2" well but T's off at the top of the well head to a 1" pipe and a check valve. (I am thinking this 1" reduction in size may become a problem?).

This 1" pipe from the well head T goes to the 1-1/4" inlet (with a reducer) of a 1/2hp pump (about 45' away horizontally) connected to a 40 gallon pressure tank to which the pump is mounted on top. Not sure of the model number of the pump, but the brand name is a Red Jacket and I am 99% sure it is a Jet Pump just by comparing the looks of it vs centrifugal pumps on their website. It is the most typical well pump you see doen here in South Florida. I am also pretty sure the well is no deeper than 20'. The outlet on the pump is 1" also and as I said before, EVERYTHING is 1" CL200 PVC pipe after the pump.

Ok, so I hope I painted a good picture of what I have.

It is important to note that this is a new system and has never been used/tested. I have all of the pipe in the ground, washed out and the heads on but it is not connected to the pump and valves yet. I know that the pump/tank works because it was used for the house for several years (although not sure what the pressure switch is or should be set at now that it is being used for irrigation).

My concerns (that I am aware of) are:

1) Is the 2" to 1" conversion at the well head an issue. SHould I remove it, put a 2" T/cap on the well head and run 2" to the pump. I am not afraid to dig AND I want to drop the well head below ground level anyway because I am tired of tripping on it.

2) Will the 1/2 pump stated above be enough to run what I have designed. I have no problem buying a new (correct pump) if needed.

3) Would I still use the pressure tank (with either the existing or recommeneded new pump)? If so, what should the pressure switch be set at?

4) Backflow - Since it is a dedicated well only for irrigation, is this needed?

5) Check valve - Should it be at the well head or moved to the pump inlet or does it not matter.

6) Anything else that I may not know of

So anyone that could offer advice, I thank you in advance for the help, and since my speciality is computers, perhaps I can repay the favor for someone in the computers forum.