I installed a rain head coming out of the ceiling in the shower. I used 3/4" pex for increased volume and as protection against freezing as it is in an attic space. I insulated very well over the pipe that lays just on top of the drywall and has at least 12" of insulation over the top of. The probLem is it takes FOREVER for the rainhead to drain. I'm talking about 20 minutes! It's not just draining the rainhead (which I know can hold a lot of water) but it is draining about 3' of the 3/4" pipe that lays on top of the drywall. I thought about installing a U shaped rise just above the rainhead that would at least keep the 3/4" pex from draining, but then there is the concern of the water in that pipe freezing (although that seems unlikely but still a possibility).
Just wondered if anyone had any suggestions.
Thanks

The head and all the horizontal pipe will drain. Not much you can do about it unless you want to put a valve on the drop nipple.

if the head has a flow restrictor, take it out and inspect it. be careful not to lose it because without it the head 'may' drain faster after shutting the shower valve.

Not a plumber here but it seems excessive to be draining for 20 minutes and only a 3' section? I assume you meant dripping for 20 minutes?

My thinking is your 3' section of horizontal pipe was held in place by capillary action. Then a tiny air bubble frees up a few drops and the process continues until full equilibrium is reached.

Yes I did mean 20 minutes. Annoying when your wanting to go to bed and go to sleep.
I will try removing the flow restrictor if there is one. I know there are at least a couple of screen filters in there (maybe that's the same thing) maybe removing one or both of them will allow it to drain faster?
Thanks

The problem is that the only way air can get in to the head is through the "tiny" nozzles, and since it is horizontal the air can only enter the head as a drop of water leaves the nozzles. IF the head were even slightly tilted, the water could drain out of the "bottom" and the air could more easily enter at the "top speeding up the process.

That makes perfect sense and we did tilt the head not because we were smart enough to think that might help, but because we were just directing the spray better. But even though I didn't notice it made a difference. Thanks for the reply.



Edited 1 times.

tilt it more. The lower sprays have to be below the upper ones.

I have been reading a lot about this issue since posting this. Seems to be a very common complaint. I have read mention of some kind of a pressure/vacuum relief valve that would be closed under pressure and then open to let air in so it would drain. But know one ever gives a specific part # or reference to such a thing that could be incorporated into a rain head set up. Does anyone know of such a device?
Judging from the # posts on the internet regarding this complaint, I think this would be a good thing to invent I think you'd make a fortune!

It is a simple "Vacuum relief valve" available at most plumbing suppliers and ALL solar heater companies. Basically, it is a valve with a ball in it that floats to seal the opening when water is flowing, then "drops" to open and let air in when the flow stops. It would go at the high point of your shower piping.