3DJH 31-5000750 Rev. 1Figure 26. Low Pressure Switch (S87) Sequence of Operation (All Units)Y1 DEMANDOR COOLINGDEMANDLOWPRESSURECLOSED(S87)CONTACTORENERGIZEDSUCTIONPRESSURECUT-OUT ISIGNORED FOR90 SECONDSLOW PRESSURE(S87)CONTACTORDE-ENERGIZEDANTI-SHORTCYCLE TIMERBEGINSINCREMENT5-STRIKECOUNTER 1LED ALERTCODE / ORSERVICE SOONALERT 410DISPLAYEDANTI-SHORTCYCLE TIMERENDSCONTACTORENERGIZEDWAITING FORPRESSURETO RISE ABOVE40 PSIGOUTDOOR AMBIENTTEMPERATURE IS 15ºFOR BELOWSWITCH IS CLOSED OR35-STRIKECOUNTERREACHES 5WITHIN A SINGLEY1 DEMANDLOWPRESSURELOCKOUTLED ALERTCODE / ORSERVICE URGENTALERT 411DISPLAYEDSERVICEREQUIRED 2LED ALERTCODE / ORSERVICE SOONALERT 410DISPLAYEDSERVICEREQUIRED 2NORMALOPERATIONCLOSEDCLOSEDOPENOPENOPEN CLOSEDCLOSED1. The thermostat terminates demand when the contactoris de-energized. If demand is satisfied when alarm isnot active, the 5-strike counter resets.2.door control (A175) R terminal.3. The low pressure switch is ignored whenthe outdoor temperature is below 15°F.LOW PRESSURESWITCHS87NO

Haier GE Appliances NS22HM Service Manual