What are these plumbing elements?

Long-time lurker - 1st post

Setting up a weekday cottage that will halve commute to NY. Doing work on the cottage to offset rent and the first order is the plumbing. This cottage in CT is at the bottom of a 50' rock that the mainhouse sits on. The iron waterline main that feeds the cottage runs down this rock and connects to the kitchen of the little house (hot water heater is located in kitchen).


Last winter these unidentified plumbing elements burst in the unoccupied and unheated cottage. The 2 vessels were shaped like large (12") co2 cartridges and were located under the kitchen sink - presumably one was for the hot water line and the other one for the cold. They are thin walled, which is probably why they were the first to burst. My question is: what are they and do I need to replace them, or can I just bypass them?

Sorry for the long post - couldn't find any other threads matching this description, this site has really been helpful, thanks.

Sound like hammer arrestors.

Like Jimbo said, they are most likely hammer arrestors. You dont need them unless you have water hammer.

If you could take a picture, that would help as well.

things

Either manufactured hammer arrestors, or machined air chambers.

Dead - on guys




The main house has water hammer in abundance (didn't know that term until now, but the condition is certain), so I assume that would be the case here as well, thanks!