PM columnist Ray Wohlfarth, author of “Lessons Learned in a Boiler Room,” has a new book on the design and installation of replacement hydronic boilers — “Lessons Learned: Connecting New Boilers to Old Pipes.” It is a must-have for anyone that designs or install commercial hydronic boilers. Topics covered include sizing a replacement boiler, venting the new boilers, estimating boiler efficiency, connecting to the existing pipe and choosing the correct boiler type, as well as more than 60 pages of heatig formulas.  AEC Store.