Carrier PG8JEA Installation, Start-up, Operating And Service And Maintenance Instructions

47room thermostat, momentarily turn off the FAN switch orpush button on the room thermostat for 1--3 seconds afterthe blower motor BLWM is operating. The furnace controlCPU will shift the continuous--blower speed from the fact-ory setting of FAN to HEAT speed. Momentarily turningoff the FAN switch again at the thermostat will shift thecontinuous--blower speed from HEAT to COOL. Repeat-ing the procedure will shift the continuous--blower speedfrom COOL to FAN speed. The selection can be changedas many times as desired and is stored in the memory to beautomatically used following a power interruption.5. Heat pump(See Fig. 25 -- 32 for thermostat connections.) When in-stalled with a heat pump, the furnace control automaticallychanges the timing sequence to avoid long blower offtimes during demand defrost cycles. When the R--to--W--and--Y1 or R--to--W--and--Y1--and--G circuits are ener-gized the furnace control CPU will switch to or turn on theblower motor BLWM at HEAT speed, and begin a heatingcycle. The blower motor BLWM will remain on until theend of the prepurge period, then shut off for 24 secondsthen come back on at HEAT speed. When the W input sig-nal disappears, the furnace control begins a normal inducerpost--purge period and the blower remains running atHEAT speed for the selected blower--OFF delay periodthen switches to low--cool speed (same speed as FAN). Ifthe R--to--W--and--Y1--and--G signals disappear at thesame time, the blower motor BLWM will remain on forthe selected blower--OFF delay period. If the R--to--W--and--Y1 signals disappear, leaving the G signal, theblower motor BLWM will remain on for the selectedblower--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, orR--to--W-- and--Y1--and--Y/Y2--and--G circuits are ener-gized the furnace control CPU will switch to or turn on theblower motor BLWM at HEAT speed, and begin a heatingcycle. The blower motor BLWM will remain on until theend of the prepurge period, then shut off for 24 secondsthen come back on at HEAT speed. When the W input sig-nal disappears, the furnace control begins a normal inducerpost--purge period and the blower switches to COOLspeed 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--Gsignals disappear at the same time, the blower motorBLWM will remain on for the selected blower--OFF delayperiod. If the R--to--W--and--Y/Y2 or R--to--W--and--Y1--and--Y/Y2 signals disappear, leaving the G signal, theblower motor BLWM will remain on for the selectedblower--OFF delay period then switch to continuousblower speed.Wiring DiagramsRefer to Fig. 54 for wiring diagram.TroubleshootingRefer to the service label. (See Fig. 50.) The TroubleshootingGuide (See Fig. 55) can be a useful tool in isolating furnaceoperation problems. Beginning with the word “Start,” answereach 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 operationsequence.PG8MEA