Device to measure run time on my boiler – i.e. hours meter?

Is there an inexpensive device I can attach to my forced hot water oil boiler — I’m thinking of an hours meter that you see on boat engines — that… Is there an inexpensive device I can attach to my forced hot water oil boiler — I’m thinking of an hours meter that you see on boat engines — that…Read MoreGreenBuildingAdvisor