Originally Posted by runhard
Is there a reason I can't use refrigeration copper tubing instead of type L, M, or K? .
I'm no plumber but I worked in a Plumbing supply store for a few years after high school...10 years back so this info might be not of much help. but L,M, and K refer to the thickness of the copper pipe, and depending on the application L,M, or K copper is required for that application to be up to housing code. as for the composition refer, or pipe there is no difference except the thickness of the tubing.
I used refer tubing in my HERMS, I think the most important thing is to get as much tubing in as possible so you get the most efficient and complete transfer of heat.
hope that helps a little