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Gas boiler sizing - please help/critique
I’m considering the following boilers for my 1,300 sqft ranch house – located in Doylestown, Penna (ZIP 18901).
• Bosch Greenstar 57
• Buderus GC144/3
There are two underfloor radiant zones – each is ~650 sqft (~16,000 Btu).
Envelope heat loss is ~26,000 Btu @ 50F temperature differential - ~30,000 Btu @ 60F.
Either solution will use an SST150-40 for domestic hot water.
I am heating with propane.
• Are these units sufficient for my needs?
For the Greenstar:
• What is the minimum output rate of these units with propane?
• Is the radiation from one zone sufficient to elicit the minimum output rate at condensing temperatures?
For the Buderus:
• Will I have issues with this unit short cycling as it doesn’t turndown?
Thank you all for your insights.