Sizing Replacement Boiler

Kraft570

Hello

I am looking to replace a steam boiler in my grandfathers house.

The current boiler is a Peerless 61-05 STDG-SP
404 Square feet Steam
97,000 BTU/HR OF steam

Natural Gas

I went throughout the house and calculated all the radiators using Weil McLain radiation sizing chart and came up with 326 square feet of steam 78,000 btu/hr.

Should I go with a boiler that matches my calculations or one that is a closer match what is in there?

I have pictures and more information if any one can help with some knowledgeable guidance

Thanks

bburd

If the steam pipes are properly insulated, there is nothing unusual about the system and you are sure of your numbers, select the new boiler to carry 326 ft.² of steam.

Oversizing of boilers and furnaces is an unfortunate but very common practice. It’s unusual to find a steam boiler that is not too large for the load.

HydronicGuru

I assume that since you are using a Weil McLain radiation sizing chart, you intend to install a Weil McLain steam boiler. If this is the case, you have a few questions to ask.
1. Is this the original boiler to the system? Could someone else have calculated wrong.
2. Are your calculations correct? I only calculate a difference of 78 Sq. ft.
3. Do you plan to install a Weil McLain?

Weil McLain would be an easier decision as the EG-40 is 325 Sq. ft. of steam with a 6 inch flue.
While the EG-45 is 392 Sq. ft. of steam with a 6 inch flue. You would not want to lower from your calculations. However, 392 is now only a difference of 12 Sq. ft. from your current setup.
Let's see what others suggest.

EBEBRATT-Ed

I would use the EG-40. Don't forget the boiler has a 33% pick up factor built in

KC_Jones

Agreed, with a calculation of 326 get the EG-40, no way would I go to the 45 for 1 sq ft of radiation.

From everything I’ve heard, read, and seen, I’d assume the previous boiler is always oversized.