Abstract: An apparatus for detecting a loss of refrigerant and air pressure in a refrigeration/heat pump system having a low pressure refrigerant line and H.V.A.C. ducting, the apparatus comprising: a pressure switch fluidly communicating with the low pressure refrigerant line, responsive to pressure changes therein; a vacuum pressure switch fluidly communicating with a portion of the H.V.A.C. ducting, responsive to air pressure loss therein; a signaling circuit having an enabling DC power supply, operatively associated with the pressure switch and vacuum pressure switch, and two pairs of green and red LEDS for conveying to the operator when the refrigerant pressure drops below a predetermined valve indicating a refrigerant loss or clogged, dirty condenser or evaporator coils, and when air pressure within the H.V.A.C.