Boiler Size

oilwizard

Why do you want to oversize the boiler??? If the calculations come up to x amount of btu's, then that is all you need, unless you plan on adding to the house. The btu number is the required amount needed to heat the whole house, and most times not all the zones will be calling at once. If you need only 40,000 then go with a G115 with a riello. And add a st150 for the domestic
Joe

Steve Luciani

Boiler Sizing

Finally getting around to putting heat in my home after heating with a coal space heater for the last 11 years.

I used the slant fin heat loss calc. to come up with a boiler size. I was shocked to come up with only about 40,000 btu,s .This does not include my un-insulated basement
and indirect fired water heater.I've also run this on several other programs and get similar #'s.

I'm an HVAC tech., and so have some contacts in the industry. Most guy,s who supposedly are knowledgable just say "Put a 3 section in and don't worry about it". Obviously, there is more to it than that.

I've decided to go with an oil fired Buderus with an indirect hwh,3 zones of base board, and 3 zones of radiant floor.

How much beyond the heat loss # should the boiler be?

oilwizard

Basement

If you didn't figure the basement and want to heat that, add that to the total load, I bet you will still be able to use a 115/3.
Joe

Boilerpro_3

You may need some extra btu's for DHW

with that small of a heat load. I'd figure out the expected DHW load and check into this. Don;t be too shaken by the small heat loss number. My 2800 sq ft 1906 frame home with 700 sq ft of glass only comes out to 52,000 btu/hr @70F delta tee. The biggest boiler I almost ever install in a home is 140,000 input.


Boilerpro