A method of controlling a heating system including at least a first stage heat pump and a second stage auxiliary heater, and a control that implements the method. In order to reduce the wearing of the electrode, the strip is formed from at least two metal strips, which are arranged one atop the other and which are made of different materials. In addition, a lubricating oil supplying structure is provided for a valve apparatus for further increasing the oil supply amount to achieve a further increase in the speed of the engine.