Body spray draining

I recently had a new Moen 275 vertical spa shower installed. The shower is basically 5'x5' and the ceiling height is a little over 9.5'. Two body sprays are installed on one wall and the other two sprays are on the opposite wall. Both sets of sprays have a balancing loop and are connected together through the attic.

The water flow goes like this:

Hot and cold mix at the mixing valve.
mixed water goes to diverter
from the diverter the water goes to the top of the shower then is tee'd
each leg of the Tee feeds one of the balancing loops.

Here's the problem. When the diverter is closed, the body sprays remain on for over a minute. One of the sprays has water shooting 3-4 feet for about 45 seconds. I know that this is due to the pipes draining but don't know how to fix the problem.

The builder's plumber said that it is normal for the sprays to drain for up to 30 seconds (per manufacturer's literature). I have to question whether this covers a 4 foot stream.

Of course because the pipes are empty the sprays spit and spudder for some time after the water is turned on.

Is there any way to remedy this problem short of repiping the shower?

http://www.moen.com/shared/pdf/275sp.pdf

Running the balance loop in the attic and probably a large pipe means you've got a fair amount of water stored in them and gravity providing some pressure available. Not sure there's much to do about it. If you had a "toe tester" (i.e, a tub spout) with a divertor, it, being the lowest point would drain off the water quickly.

drainage

Adding the balancing loops, which was probably not really necessary, created additional water volume. There is no way to prevent the stored water from draining from the lowest body spray, unless you could find some nice looking inline spring loaded check valves to prevent them from drawing air.

I thought about check valves but I would have to find some that would cut off flow at about 4 psi. Assuming that the there is 8 feet of 3/4" pipe installed vertically I will have approximately 96 inches of water which converts to 3.468 PSI.

I'm not sure what the required DP is for residential check valves. And as you mentioned they would have to be fairly decorative unless we're going to remove tile.

Thank both of you for the input

check valves

All you would need is a valve that withstands the pressure differential between the highest and lowest heads, which would be less than a pound if they were 2' apart vertically.

HJ

All of the heads are at the same level. There are two sprays (with a balancnig loop) on one wall and two more (with a seperate loop) on the opposite wall. The supply line goes up the wall and into the attic. The pressure on the spary body is due to the 8ft of head prussure.

I made a word doc with a pic but t was blocked so here's a bmp.

I made a word doc with a pic but t was blocked so here's a bmp. Hope that you can see it. I gotta go catch aflight.

Lawn sprinklers sometimes use an anti-drainback fitting, which in essence is a spring check. Don't know if you could find one of those in a material suitable for inside plumbing.