H20PS(M)  series pressure switch is a miniature pressure switch. It controls the circuit open or close on pressure of the controlled medium increase or decrease. It is widely used in refrigeration system, oil pump, air pump and the other industry equipment which require to adjust the medium pressure to protect system.

The working principle of H20PS series pressure switch is: When the pressure of the controlled medium rises to a predtermined value, the metalflip disk will flip and drive a set of electrical contacts by means of a transfer pin. When the pressure of the controlled medium drops below another predetermined value, the snap disk will flip to the original state, to make the contact terminal close(or open). In the way the switch function is realized.

There is a slight difference between the working principle of H20PSM series pressure switch and H20PS series pressure switch: When the pressure of the controlled medium decreases, the switch can not reset automatically. And just only as the push botton is pressed, the circuit will reset to the original state.