I think it should be on year round, not just because it's needed, but also because customers notice if the high-pressure
soap is cold.
I don't know the temp it's running - I try to keep it hot enough that I can stand to stick my hand in it for a few seconds without getting scalded. The exposed fittings can get uncomfortably hot if it's any higher. The thermostat says 110? at that point, but I don't think that's accurate.