mas985-thanks. so if i understand you, when somebody has 2 loops and they are not in balance the waterflow will come through 1 loop and not both loops equally? thats why i am getting all the pressure coming out of just 4 jets and not all 7?
Water likes to flow the path of least resistance, then again so does everything else. So unless each path is equal in length, fittings and jets, water will tend to flow more down the path with less head loss. This equalizes the head loss down the paths but the flow rates are different.
is rollin thunder correct about the 8 jets?
Even if you had 4 jets on each loop, it doesn't mean that the paths would be balanced. There are other factors.
also,why would the plumber use different size pipe for the loops?
Sometimes it is more about convienence than a good design. I have seen builders do a lot of stupid things so it wouldn't surprise me. It is unlikely that he did but you should check anyway.
i will try playing with the valve and see if i can get equal flow to both loops. the builder did tell me i would lose some flow when i turned on both loops but i thought the flow would be equal to all 7 jets. if i have enough suction it seems a simple fix would be to add a 1.5hp booster pump to the 3 jet loop and leave the 2.5hp for the 4 jet loop. but can this be done if i dont have 3" suction line?
It would be a bit iffy to have a 2.5 HP pump and a 1.5 HP running on a single 2.5" line. Double check the design and also see if you have multiple lines. Three 2" lines or two 2.5" lines are equivalent to a single 3" line.
if the pressure side measurements come out high does that mean i can not add power to fix the problem? i will get you the other info you wanted but based on the info you have what do you think is the chance that i will have to rip-up the spa?
I don't think you should have to rip up the spa. This problem should be fixable with the plumbing that you have. What is really important though, is to fully understand how the PB intalled/designed the plumbing. Otherwise, it is guess work.