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Modcons, boilers with a lower min fire rate than 8kbtu/hr? Future?
It seems like the min fire rate on modcon's has stuck at or around 8000 btu for a couple years.
I would love to see a 4000-5000btu/hr min, it means substantially less cycling if you have a micro-zoned system, and if you still need a buffer it can be much smaller.
Has any manufacturer come out with one, or are they even working on it?
It seems like the high turndown ratios of 10:1 or higher are reserved for 80kbtu or higher boilers. Most of the 50kbtu boilers seem to be a throttled version of the manufacture's 80kbtu and have similar low fire rates.
Is there some sort of technically reason that makes combustion control difficult at low fire rates.