most economical scenario

Live/Learn

Hi Wallies, Question! which is more economical a small fire (low firing rate .75 nozzel) running longer to come up to temp. or a larger fire (1.05 nozzel that reaches high point faster? Both firing rates heat my home adequately. I seemed to have burnt about the same amount of fuel this year(using .75) as I did last year (1.05) which was a colder Winter I think. Which is better for the boiler? I would think longer run times. Thanks Live/Learn

Brad White_51

I would think the lowest firing rate

consistent with heating the house in a reasonable amount of time and keeping the stack warm enough.

Take the scenario to an extreme in both directions:

Say you put in a 2.0+ GPH nozzle. You would over-fire and waste a tremendous amount of fuel, have high stack temperatures and probably incomplete combustion.

If you put in a 0.50 or less nozzle you run the risk of condensation, low passage and flue temperatures and long firing times to get to temperature.

Same philosophy re: modulating gas- lower fire is more efficient due to higher surface area to combustion gas volume ratios. But the boilers are built to take it.