boiler sizing help please

TomM

I decided on a Burnham Independence Power Vent gas fired boiler for my new install.

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I have 239 sq ft EDR.

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Looking at the Burnham charts, the INPV4 will heat 271 sq ft EDR, and the INPV5 will heat 363 sq ft EDR.  

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If i take 239 sq ft and add in a pickup factor of  1.33x, then i get 310 sq ft EDR.

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BUT, Dan says in TLAOSH that you should figure normal radiation (239), multiply by 1.5, and convert to MBH (x240) and select the boiler from the DOE Heating Capacity column in MBH. 

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That means that I need 87,000 BTU DOE Heating capacity, which is the INPV4, right on the nose. 

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BUT, i don't see anywhere that Burnham's ratings for sq. ft of steam add in any pickup factor (like slant Fin's does). 

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Any experience with this model?  It seems like the INPV4 would be a perfect fit, but i don't want to risk being too small. 

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I have a 2 pipe air vent system with no insulation.  (will be insulated in the basement in the future) I have three risers with two radiators each.  Mega super mondo venting on the top of each riser.  Also, we turn off the radiators on the third floor sometimes if it gets too hot up there.  My only worry with pickup factor is that the horizontal length of one riser goes under the kitchen crawlspace for about 20 feet, which is unheated.  I'd like to add a hot water loop in the future, but i know that you don't size up for that.

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Thanks!  (burnham spec sheet attached)

Mark N

IN-4

I have 260sqft of EDR in my home. I have an IN-4 and it works great. I have no short cycling and run at very low pressure.



Mark

gerry gill

You dont have to add the pick up factor Tom,

If you have a certain size sq ft of iron, and a boiler is rated for that square feet, thats it..the pickup factor will have automatically been added in by the manufacturer. Thats if your sizing by square feet..which is what we always do..that way you can disregard all the other btu stuff on the label.

TomM

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Thanks guys!