oil to gas conversion

shawn indrerd

i have oil burning steam heat right now, and i am switching to gas heat. i wanted to make sure my installer is getting me the right size boiler.

i calculated the EDR for all my radiators (besides 1- will get to that later)

the total is 92,280 BTH/H

however, 3 of the radiators are SUNRAD recessed that total 175.5 sq. ft of radiation. (3 radiators that are 26 sections each) how does the fact that they are recessed and my house has little (to no) insulation change the EDR calculation?

also how do i calculate the radiation for a cast iron baseboard radiator (being used for steam heat) that is in an unreachable place? i can see it but not actually measure it.

also does the fact that my main lines in the basement are not insulated in many places effect it?

i am including a pic of the plate from my old boiler.

can anyone recommend what should be the lowest, and what should be the highest possible amount of BTU on the new boiler?

BobC

EDR

Your present boiler is rated for 384 sq ft of steam so it should be feeding close to 330 sq ft of radiators for good operation. With steam the EDR (square footage of connected radiators0 is the best way to go because you want to match the boiler to the connected EDR (plus a pickup factor).



Recessed radiators on exterior walls without insulation and going to lose a lot of heat. At the very least get some heat barrier foil behind them to help reflect the heat into the room. Also see if there is a way to get some insulation above them so it doesn't just shoot up the wall. A lot of old houses are balloon framed and that means a recessed radiator may be feeding a lot of it's heat into your attic and to the outdoors.



BTW you should insulate all the piping you can in the basement, use a minimum of 1" pipe insulation. Uninsulated pipe adds to the load on the boiler and effectively increases your connected EDR. i really have to specific knowledge of cast iron baseboard so hopefully somebody else will fill that in for you.



Bob