It's all pretty simple. Those 2 unit heaters came out of a high school kitchen I remodeled. I'm sure they were original to the 1958 original construction. They were a mess, though, with 40 years of kitchen grease all up in the coils. After I got that all cleaned off I was amazed at how good they were. My only complaint is that they were designed to have live steam heating them instead of hot glycol. So they don't work as well as they could. One thing I think would help is if I found some slower-much slower-fans. These create quite a windstorm when the slats are all open and I believe that much wind don't let the coils heat up and stay at a decent temperature..
I still have 2 minor drippers that I need to fix before I finish the pipe insulation, but I need to drain it down some to do it, and I fear that the drain valve on the bottom of the water heater will break. I am looking for a big, flat pan that will hold 50 gallons before I attempt that.
As for the pump, it's just a simple Bell & Gosset circulating pump. A plumber buddy of mine had it laying around and gave it to me. He didn't want it for anything, just leftovers that we all bring home from jobs.
