This question must be bread and butter to you. We recently purchased a house in NY. We have an oil furnace with a honeywell triple aquastat. The house came with a gas water heater so we do not need to divert water away from the radiators. From what I have read, however, it seems better to use the LO and DIFF in all seasons for best maintenance and to prevent cold starts. I have read conflicting information about the best off-season vs heating season settings for Hi, Lo and Diff. Currently, for reasons i don't understand, the boiler is cutting off when H2O is LO + DIFF (not just running up to Hi-10). It is set at 180, 140, 20.
Thanks for help with what must be a very naive question!