I believe that the higher end units have auto reset pressure switches, if you look down the inside of the unit, you will see one or two pressure switches welded to the lines,,,there are about the size of a "C" cell sized battery, with 2 wires running into them, if it is a manual reset type there will be a small rubber coated button on top, between the 2 wires. If this has been helpful, please rate me, and/or contact me back with any further questions. Sincerely, Paul Gibson
Answers & Comments
I believe that the higher end units have auto reset pressure switches, if you look down the inside of the unit, you will see one or two pressure switches welded to the lines,,,there are about the size of a "C" cell sized battery, with 2 wires running into them, if it is a manual reset type there will be a small rubber coated button on top, between the 2 wires.
If this has been helpful, please rate me, and/or contact me back with any further questions.
Sincerely,
Paul Gibson