I am re-doing our guest bathroom and ripped out the fiberglas shower shell in order to do a full tile shower. I am also replacing the shower valve as well. I was a little confused when I saw the plumbing going to the original valve. There is a 10" piece of 1/2" copper coming up from the feed to the valve that is capped off. There is one on the hot and one on the cold. What are they for? I can post a picture if needed.

Thanks

It be nice to post a picture of it, Thanks.

John

Here's a pic

http://img7.imageshack.us/img7/6439/20100130191727.jpg

It looks like water hammar arestors to prevent the water hammar, see the image below, Thanks.

John

Is it possible to make hammer arrestors? Because these are obviously just made from 1/2" pipe coming off a tee and capped off.

When you fill a system with those capped off pipes the capped off pipe gets filled with air. Air is compressable, water isn't so the air absorbs the resultant high pressure wave when a valve shuts off. Eventually, this type of home made chambers fill with water so draining and refilling the pipes is necessary.

The commercial varieties may have sealed chambers with springs or a fluid and can be smaller.

It's good to put them at the water meter and washers, dishwashers and toilets. These valves shut off abrubtly. The higher the column the better.

Thanks for the clarfication. I'll make sure they are left in the system when I replace the valve.