Pressure controller is a controlling switcher through pressure signal．It controls compressor starting or stopping directly in order to protect system working in safety status through the signal of condenser pressure or compressor suction pressure．

　　When system controlled pressure goes up or down，bellows in pressure controller will be compressed or lengthened，so push the switcher by lever arm in cut－on or cutoff status．So that it can protect system working in normal status．

　　 1．The control Should be located at position with no vibration or less amplitude，when assembling or tightening the nut on the tubefor pressure transmission，be sure to use tow wrenches in opposite directions in order to avoid the injury of the bellow joint．
　　2．Connect wlres in accordance with the supply wiring diagram to avoid damage and abnormal operation to the control．