View Full Version : mixer rough in?
02-04-2007, 10:49 AM
I'm about to rough in my new shower mixer and was planning on coming from my hot and cold feeds via 90 degree elbow to the mixer. I noticed on my old valve they connected it via tees instead of elbows and the top connection of the tee was just connected to about a 8inch pipe then capped.
was this for expansion to control water hammer and should I plumb my new mixer in the same way?
02-04-2007, 10:53 AM
Yes, the 8" piece was an air chamber. Good theory, doesn't work, because from natural turbulence in the pipes, it just fills with water quickly.
If you have an issue with water hammer, get a commercially available hammer arrestor, which use a bladder.
The longer the air chamber is, and the larger the pipe diameter, the longer it will be before it becomes waterlogged, but it will happen eventually. And once it does there is no practical way to regenerate it.
02-04-2007, 02:34 PM
"And once it does there is no practical way to regenerate it..."
other then shutting off the water, draining the system and turning it on again.
02-04-2007, 05:44 PM
Usually there is a vacuum that prevents the airchamber from draining.