Pump/well output calculation
After an aborted attempt, paid to have well put in. I told them I had most equiptment (pump, PSR, Controller, Rain sensor, wiring) and only needed dropping the well and 220 circuit to get everything running. They were estatic when they arrived and saw Hunter equiptment rather than HD/Lowes. Eyes bugged out when they saw what I paid through Sprinkler Warehouse as cheaper than their discount, so printed the web page for their followup.
While they did neighbors and had good references, with my construction background, it reinforced why I prefer doing myself. Have to rewire the low voltage as spliced in-line (and cut excess) the rain controller rather than routing to controller posts so override doesn't work. Worse, instead of putting in a 15amp 220 at the main ten feet away, they spliced into the 60 amp Heat Pump circuit at the outside cutoff switch. I am not even sure that meets code, but will get that corrected with a dedicated 15 AMP circuit later.
Big question now in pump output, and I want to be accurate for the circuits. I calculated with Jess Strykers "dry method" at 26GPM with assumed 50PSI. I am unble to do the more accurate "wet method" as there is no pressurized holding tank and it is/will be straight pump with controller/PSR system. When I gave Toro, Orbit, and Rainbird their requested data (two wells with 6' wellpoints beginning down 25 ft to clear sand, static water at 7', drawdown to 10', with 1 1/2 HP pump) they estimated around 16-18 GPM on the same estimated 50PSI and designed systems accordingly. I know the pump puts out a lot of water. With the 1 1/4 output pipe resting 2 1/2 ft above ground on a sawhorse, the water was hitting the ground 4' away, and filled a 5 gal bucket in 6 seconds.
As you can see, I am not concerned about the output volume. It is the pressure of that volume as my observation has no pressure buildup - just straight output. To get a more realistic reading should I put in 1 circuit, and design in a pressure guage at the pump, then adjust the circuit size according for a 50PSI? Alternately, if not a permanant pressure guage, place a spigot on the output line as the well drillers suggested (to wash my car - yeah right), then use a spigot pressure guage I already have.
Any other suggestions? Assume my "dry method" calculation is more accurate?