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Gravity system conversion
This is my first gravity Ive done ALOT of reading if anyone has pointers on setup im all ears. had a ATCO coal boiler that was converted to oil decades ago Im guessing orig boiler was 1930s. its a ranch w dual mains and dual returns 2.5" The piping is overhead in the whole house and drops to 2 pipe rads i each room, the biggest room has 2 rads. There are standard Ts no monoflow or anything special the heat was terrible w the old boiler its a rental and tenants complained of huge fuel bills, house is uninsulated and original crap windows.
Anyway modern boiler going in heat loss says around 80k btus needed they want cheap so something around 100k input. I did all the pipe surgery yesterday and had my guys cut the old boiler apart and remove. got bushings and reducers and am ready to pipe 1" at boiler connects. Will be piping with a bypass loop with ball valves to adjust flow and ball vavles on each supply main in case balance is needed one loop is longer more rads. From what Ive seen and read here I want to pump away from boiler on supply I will be using the right circ I read the links on pumps and also the educational section on gravity. My question is really is where to bring in supply water the air scoop xpansion tank and if needed check vavle.
I was going to come up off boiler 2 ft elbow into straight run over 18" for air scoop and between that run do water feed and valve/drain for purging. after scoop/xpansion tank go vertical to circ then check valve then T in for bypass loop then ball valve before splitting into 2 runs to tie the 1"into the mains. On return I'm simply tieing in the mains to 1" and T into the bypass loop w a ball valve into boiler. budget job for extended family member no funds for mixing valves or anything fancy they wanted to use a used boiler its like that lol.