Do condensing boilers come in as small a size as 25 - 30 000 BTUs? The smallest I've seen so far is 45 000 BTUs.

If not I assume a condensing hot water heater is the next best thing?

John

I look to minimum output on many of my projects (roughly 15mbtuh), sizing for the smallest and most demanding zone.

Most of this can be controlled with proper design, including operating temperature and parasitic pump loads.

No other condensing appliance will operate at the same thermal AND system efficiency as the incomparable ModCon high efficiency boiler.

if you really needed much smaller, the idea of going with a high efficiency source is itself probably questionable.

that said, buffering your demands can solve any issues with sizing mismatches, within reason.

Thanks for the info.

Who makes a mod/con in the 25-30 000 BTU range?

John

no one: that's the minimum modulation for most boilers, with a few going lower such as the Ultra 80, Solo 60, and Munchkin T50 all with sub 20kBTU mininum modulation rates.

Is there an application of the 30 K btu's? ... because you might find other answers that would be economically viable.