My 5 year old indirect started leaking (a lot) Enough so that the aquastat got rusty and stopped working. I had a spare boilermate that I had picked up a few years ago for $75 but I got tired of looking at it so I sold it last year on CL for $450! Apparently a lot of people have leaking indirects and these things sell quickly. I spent six months looking for a good deal on a replacement and eventually found two Triangle Tube TR120's for $200. So this whole project didn't cost too much. I hooked them up today as there was way too much leaking out of my existing water heater. I have one set up as a pre heater -- might eventually add solar. The other one replaced the existing heater. Between the two DHW inner tanks I have a recirculating pump. This way when I do solar if the pre heat tank gets above say 150 I can have the pump come on and heat the primary tank. Until then I will manually turn that pump on whenever the woodboiler is running and I have extra btu's available.