This new home calls for a heating load of 65,000 btuh @ 0 degrees F outside ambient. Load calcs done using wrightsoft software. There has been 18000 btuh of radiant staple up installed. The entire house has been ducted and conected to a first co a/h with a hydro coil supplying 65000 btuh @ 140 F water temp or 103000 btuh @ 180 F water temp. There will also be a 50 gal. indirect water heater connected to this boiler. The boiler does have priority zoning. Which GB would you recomend? The GB142/30 has a rated output of 28,100-91,500 btuh @ 176/140 F water temp or 30,700-102,400 btuh @ 122/86 F water temp.
The GB142/45 has a rated output of 42,500-142,000 btuh @ 176/140 F or 47,200-158,000 btuh @ 122/86 F .