Replacement Boiler Sizing 1

danmayer175

The radiators I use now total 355 sf EDR and heat the house great. There is a runout to a 40 sf radiator (not included in 355 connected) in the garage that we've never used, but I wouldn't mind having the option if we renovate the garage some day. Is it 1) OK, 2) a bad idea or 3) a really bad idea to size the boiler for that additional load at the risk of running oversized a bit? How bad would it be to run 355 sf of radiation on a Megasteam 396?

mattmia2

Remember there is a 30% pickup factor subtracted from the rating of the boiler so the 396 sq ft actually produces 514 square ft and the 288 square ft actually outputs 374 square ft. Either will likely work on a properly working system but I would probably go with the 396 and try to under fire it a little.

Jamie Hall

Shouldn't be a problem. It may tend to cycle a bit — but I'd not worry about that, and it would give you the capacity to add that garage when you want to.

Steamhead

https://forum.heatinghelp.com/discussion/comment/1846921#Comment_1846921

This.