Carrier 58PHA/PHX instruction manual Heat pump, Wiring Diagrams, Troubleshooting

5.Heat pump

(See Fig. 25 - 32 for thermostat connections.) When installed with a heat pump, the furnace control automatically changes the timing sequence to avoid long blower off times during demand defrost cycles. When the R-to- W-and-Y1 or R-to-W-and-Y1-and-G circuits are energized the furnace control CPU will switch to or turn on the blower motor BLWM at HEAT speed, and begin a heating cycle. The blower motor BLWM will remain on until the end of the prepurge period, then shut off for 24 seconds then come back on at HEAT speed. When the W input signal disappears, the furnace control begins a normal inducer post-purge period and the blower remains running at HEAT speed for the selected blower-OFF delay period then switches to low-cool speed (same speed as FAN). If the R-to-W-and-Y1-and-G signals disappear at the same time, the blower motor BLWM will remain on for the selected blower-OFF delay period. If the R-to- W-and-Y1 signals disappear, leaving the G signal, the blower motor BLWM will remain on for the selected blower-OFF delay period then switch to continuous-blower speed. When the R-to-W-and-Y/Y2,

R-to-W-and-Y/Y2-and-G, R-to-W-and-Y1-and- Y/Y2, or R-to-W- and-Y1-and-Y/Y2-and-G circuits are energized the furnace control CPU will switch to or

turn on the blower motor BLWM at HEAT speed, and begin a heating cycle. The blower motor BLWM will remain on until the end of the prepurge period, then shut off for 24 seconds then come back on at HEAT speed. When theWinput signal disappears, the furnace control begins a normal inducer post-purge period and the blower switches to COOL speed after a 3 second delay. If the R-to-W-and-Y/Y2-and-G or R-to-W-and-Y1-and - Y/Y2-and-G signals disappear at the same time, the blower motor BLWM will remain on for the selected blower-OFF delay period. If the R-to-W-and-Y/Y2 or R-to-W-and-Y1-and-Y/Y2 signals disappear, leaving the G signal, the blower motor BLWM will remain on for the selected blower-OFF delay period then switch to continuous blower speed.

Wiring Diagrams

Refer to Fig. 59 for wiring diagram.

Troubleshooting

Refer to the service label. (See Fig. 55.) The Troubleshooting Guide (See Fig. 60) can be a useful tool in isolating furnace operation problems. Beginning with the word “Start,” answer each question and follow the appropriate arrow to the next item. The Guide will help to identify the problem or failed component. After replacing any component, verify correct operation sequence.

58PHA

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