"Michael Gallagher" wrote in message
It will shut off when the demand is low enough ....

Just so I'm clear on this, "demand is low enough" means "the temp gets
to the setting on the thermostat," right?

Right. actually, it is more complex than that but no, it will not be
running 24/7. You will probably see less fluctuation in the temperature
also as the boiler modulates and decreases the output at times.


Sorry for seeming to somewhat anal, but this thought came to mind: The
Ultra's fuel efficency wouldn't do me much good if it runs 24/7!

Why not? Why do you care how long it runs if it is saving you money. A
roaring forest fire will put out enough heat in a minute to keep your house
heated for a season. Do you think that is more efficient than running a
candle 24/7?