[rossfingal]

A few years ago, I roughed in the plumbing in a house for my boss.
(His house - new)
He decided to add a bath on the second floor.
He took the supply lines off of the expansion chambers on the vanity,
from one of the baths on the first floor.
Good idea or not?!?

Thanks!

rossfingal

(Happy Spring - y'all!!!)

 

[Daniel Holzman]

What is an expansion chamber, and why do you have one on a vanity?

 

[rossfingal]

To try to prevent "water-hammer", from happening.
"Banging" sounds - when you turn on and off the water.

rossfingal

 

[TheEplumber]

There is an argument that says the air escapes the air chambers over a period of time and need to be recharged by draining the water system. Whether it's true or not- I don't know.

I have only installed manufactured water hammer arrestors and my state has amended the UPC to exclude arrestors on residential work- so my experience with home made ones is limited. But, I see little reason to have them on a lav. Perhaps an ice maker or washer though

If it has been a while, and there is no hammering- I'd say it's all good...

 

[AllanJ]

For homemade water hammer arrestors, consisting of a tee to a seemingly useless vertical pipe capped at the top, the air inside will be gradually absorbed by the water thus needing recharge by draining the water system.

Once in awhile the water supply has air bubbles which under favorable conditions can replenish the air in the arrestors faster than air gets absorbed.

Manufactured arrestors have a spring, piston, and/or bladder so as not to need recharging.