While some boilers will run on 120vac (mine does), most furnaces I've seen require 240vac - the blower fan is usually the culprit that uses the higher voltage.
While some boilers will run on 120vac (mine does), most furnaces I've seen require 240vac - the blower fan is usually the culprit that uses the higher voltage.
The furnaces that I've worked on here in Northern California (6-7 furnaces over 30 years) have all been powered by 120V, using a cord plugged into a standard outlet. These were all natural gas or propane furnaces in single family residences. I haven't seen a boiler since I managed an apartment building in Massachusetts in the early 1980's.