Hi Dave,

Boilder side is copper going in and out of the exchanger. Water temp I think is about 190. Pool water connections going through the heat exchanger have been my greatest source of difficulty and leaking. Sched 40, expands and contracts too much and eventually the teflon tape fails and it starts to drip. Galvanized pipe worked great for leaking but dismal for pool staining, a lesson learned. Shed 80 pvc loaded with teflon tape has worked out pretty well so far.

My exchanger is all stainless, works great but wish I went a little larger, too much hot water exiting the exchanger back to the boiler so I believe larger exchanger would have transferred more heat. Shouldn't complain though, I can raise the pool temp about 1.5 degrees per hour with the current exchanger.

Mark