Boiler Sizing Question

northernboiler

We entered a bid for replacement of steam boiler.

We performed the EDR calculation.

After measuring the radiators, we calculated they measured 517 sq. ft.



The customer is requesting only a Weil-McLain SGO boiler.

Which is fine by us.

We will be installing it using a drop header, of course.



The 2 other bids they customer received both displayed SG0-4 boilers.

We recommended an SG0-5, based on our calculations, which were done twice (by 2 different people just to make sure- a kind of fail safe)



The SG0-4 has a rating of 450 sq.ft. steam

The SG0-5 has a rating of 546 sq.ft. of steam



I really cannot see how we are over sizing the unit.



This is why I ask, the customer relayed to us that the two other companies stated that the rating numbers by Weil-McLain already "bumped up" for pick-up loss.



Are we wrong??

icesailor

Wrong:

You are not wrong.

Steamhead

If the radiators

measure 517 square feet by themselves, with nothing added to this figure, then the SGO-5 is the proper boiler.