My present gas-fired steam boiler has 2 supply lines (one goes to each side of the bldg). There is a one pipe return. I need to get a new boiler, which will be smaller than the presest oversized one (about a 200,000 btu output compared to 400,000 for the present one). Would a standard boiler of roughly that capacity have tappings for 2 supply lines or would this be a special order? From my brief perusal it seems like most online boiler sales are package deals where you get the low-water cutoff, limit, etc as part of the package. I've been doing some research online and some authorities imply that the lower the steam pressures on the limit the more efficient the system will be. In this context a vaporstat is recommended over a pressuretrol, because it allows finer calibration of cut in cut out pressures (for example cut in at .4 PSI cut out at .12 PSI, as opposed to say cut out at 1.5.) Reading the installation instructions for these package deals the part dealing with limits often has a cutout setting of 1.5 or even higher. Is this pressure consideration really that important? Could you substitute a vaprstat for one of the more standard pressuretrols offered? Does the vaporstat mfg supply instructions that are applicable to any system? Sorry for all the questions. Other than having done some internet research, and having dismantled the old non-working boiler piece by piece, I don't have any experience or expertise on the subject. What are the important factors for me to consider? Is this job doable by a novice. Any insights you can offer are appreciated.

I would like to winterize an uninhabited house using antifreeze in the hot water heating system. How much antifreeze do I need for a 3 story sytem with 2 heating zones? Can the antifreeze stay in the system year-round? Should I drain the domestic water and fill all the traps with antifreeze? Where do you get this stuff?