Question:
I want to have very little pressure (5 psi or less on the pool
> heater). How much pressure would be created by the 2 inch
> to 1 1/2 inch reduction?
Answer:
Your heater will be on the return side of the collectors and
tall climb to the roof, so it won't be getting the high pressure.
Since the flow rate will, most likely, be somewhat reduced, the
pressure through the heater will actually be less, than it is now.
31' of head is equal to 13.4 PSI, at the pump.
Here is how to plumb it. Run the 2" up to the roof, at the center
of your collector array. 'T' the 2" at that point, off into the two
1-1/2" panel headers, one to the left, and one to the right. From
the hot headers, run 1-1/2" pipe back along the top of the panels
to rejoin at another 'T' at the 2" down (return) pipe. That way
your 1-1/2" panel headers will never restrict the flow to less
than 2". You could also feed into the panels at the extremities,
and out at the center, if you prefer.
