Posted by jtown on February 06, 2000 at 05:46:05:
In Reply to: draining and refilling HB Smith boiler posted by Chris S on February 05, 2000 at 18:46:39:
Drain and refill - you shut off system, shut off make up water, run a hose from the boiler blowdown to a floor drain and open air vents up above, especially above where you are soldering to keep the water from trickling down for hours, steaming out your solder. To refill you close all the vents and the bottom blowdown and open the rapid fill until you have 5-10lbs of pressure and then go let air out of radiators and repeat the cycle. If you have helpers you can speed it up greatly or have vents open at first and add water till you get a little at lowest radiators. It can take a while. I probably wouldn't bother for two joints. The manf'r is worried mostly about whole bldgs full of joints done by people that use way too much flux. If you do flush it run the system for a couple of hours right away to get the dissolved gases out. You shouldn't need any additives. Blowdown a little water into a bucket once or twice a season and see if you get any solids. If not go more often to keep any from building up. Steam systems need it much more as air gets in and out corroding the system. Blowing down a boiler is that process. In big high pressure boilers it is done based on water tests done each shift.