3) static Pipe Head (Altitude) in feet.
Wood'nCoal wrote:how does the gauge "know" this???
Are you sure it had three needles? Usually it two needles with one having a dual scale. Sometimes the pressure needle's pivot point is in the center, in that way you can have two separate scales. One for each needle end. Today's tri- gauge would have 6 scales, English plus metric scales, a 3 x 2.Wood'nCoal wrote:The gauge on the gas boiler at my parent's old house had the three needles.