Refurbished Boilers

Rob R. wrote:2500 sq. ft....if you can't heat that with a 520 you better start looking for missing doors and windows.

I don't have the exact long-term numbers but over the past 5 years Presque Isle has averaged about 20 percent more annual heating degree days than Plattsburgh. Heating 2000 sf of old house plus addition plus modine plus DHW up there poses a lot more of a challenge than it does to almost everybody else on the forum. All I am saying is that extra care should be taken on the sizing, because that's a particularly difficult heating environment.

Mike

My boiler isn't an EFM, but I get all the same results as *RobR* stated above...w/ a 41 gallon indirect.
Point is, that it's all about the "recovery rate" of both the tank and then of the boiler together.
An 80 gallon tank has similar *recovery rate* as a 41 gallon...it just stores more of it. (volume)
More volume is good for that fast fill over size soaker tub, though.

Pacowy wrote:I don't have the exact long-term numbers but over the past 5 years Presque Isle has averaged about 20 percent more annual heating degree days than Plattsburgh.

Yes, I did the same calculation. I came up with 16% compared to my closest weather station, but your point is well made. When it comes to older homes, infiltration is a much bigger part of the overall heat loss, so wind exposure is an important consideration. Heat loss calculations tend to be more of a "guesstimate" on old homes, so I usually focus more on the performance of the existing heating system and the fuel consumed.