This boiler was recommended and installed by a big Washington, D.C. company, JONES AND WOODS. DO NOT HIRE THEM. Lots of problems because basically they had no idea what they were doing and lied to me about all the experience they have had installing these units, as evidenced by the elementary mistakes they made. Finally got the Munchkin rep. on a site visit and he confirmed that they had left out MAJOR components, like the secondary circulator pump on the supply side, as plainly specified in the install manual. Learned lots from the rep, who was great, both about improvements in the Rev. 2 version of this unit as well recommendations: this little baby puts out LOTS of water as condensate, which must be directed back into the unit by having the exhaust pipe tilted back into the house. Steams outside like a locomotive in cold weather. The condensate, however, is HIGH ACID and must be neutralized with a kit as over time it will eat through even a cast iron drain. Condensate outlet hooked directly to a floor drain is a good idea. I'm using a standard plastic condensate pump to get the water up and over into a sink, and am worried that with the PH adjuster downstream of this pump, how long can the pump last? Also, how much net energy savings can there be, given the THREE electrical devices necesssary to run this moon unit? (2 circulators and the pump). :angry: