pick up factor

Paul S_3

Can someone explain when I should add a pick up factor when sizing a steam boiler....for example on a estimate today I measured 455 sq ft of radiation....nothing is insulated its a one pipe system ....should I get a boiler for 455 sq ft (109000 BTUs)? Or should I add a factor thanks Paul s

vaporvac

Included in specs...

I'm a homeowner, but when we sized my replacement system, I believe the manufacturers included the pick-up factor in their calculations so you don't have to add it in twice. Just pick the boiler that most closely matches the edr. Others, please correct me if I'm wrong.

Rod

Understanding Boiler Rating Charts

Hi - Reading a boiler manufacturer’s rating chart can be a bit confusing. I’ve attached a typical manufacturer’s rating chart below. 



The following are 3 methods of comparison. (Note - the Net IBR ratings, already have the “pickup factor” calculated in to the displayed figure)



1. If you know the total EDR of your radiators in Square Feet, you can go straight to the IBR Steam sq.ft. column in the ratings.  (The “pickup factor” is already included)



2. If you know the Total BTUH Load of your radiators, you can go straight to the Steam MBH column. (The pickup factor is already included)



3, The only time you need to add the pickup factor is when you are using the DOE MBH Output Rating. You would only do this if you, for some reason, needed to change the pickup factor percentage.



All 3 methods arrive at the same boiler size. Most people use the first method, comparing Square Feet of Steam.

- Rod