Have recently moved & have above boiler to deal with. It works fine but there is no manual & a Google search gives no clues where to get one. Can some one let me know what the knobs do? I assume the left one is on off. Will it start automatically when turned on.The right one may be a thermosta , it is currently set in the middle. What is the pointof the pressure guage? There is a red knob marked "press to reset", does this mean restart or light? Many thanks Chevron