Carrier 558J Series Service And Maintenance Instructions page 14

Operating Sequences
The Perfect Humidity™ system provides three sub−modes
of operation: Normal Cooling, Reheat1 and Reheat2.
The Reheat1 and Reheat2 modes are available when the
unit is not in a heating mode and when the Low Ambient
Lockout Switch is closed.
When there is both cooling demand (thermostat Y1
demand) and dehumidification demand, circuit 1 will
operate in Subcooling (Reheat1) mode. See Fig. 18
Schematic for system refrigerant flow.
RDV1
VALVE
CONDENSER COIL
OUTDOOR AIR
COMPRESSOR
= CLOSED VALVE
= OPEN VALVE
= 3-WAY VALVE
RDV1
VALVE
CONDENSER COIL
OUTDOOR AIR
COMPRESSOR
= CLOSED VALVE
= OPEN VALVE
= 3-WAY VALVE
Fig. 18 − Subcooling Mode (Reheat 1) – Perfect Humidity] System
INDOOR LEAVING
LDV1
PERFECT HUMIDITY COIL
VALVE
CIR 1
TXV
METERING
DEVICE
CIR 1
EVAPORATOR COIL
INDOOR ENTERING
Fig. 17 − Normal Cooling Mode – Perfect Humidity] System
INDOOR LEAVING
LDV1
PERFECT HUMIDITY COIL
VALVE
CIR 1
TXV
METERING
DEVICE
CIR 1
EVAPORATOR COIL
INDOOR ENTERING
When there is only a single cooling demand, one or both
circuits will operate in Hot Gas (Reheat2) mode. The DSV
solenoid valve is open and the CSV solenoid is closed.
See Fig. 19 schematic for system refrigerant flow.
Subcooler/Reheat Coil
The Subcooler/Reheat Coil is mounted across the leaving
face of the unit's evaporator coil. The coil is a one−row
design with two separate circuits.
AIR
LDV2
VALVE
CIR 2
TXV
METERING
DEVICE
CIR 2
AIR
AIR
LDV2
VALVE
CIR 2
TXV
METERING
DEVICE
CIR 2
AIR
14
RDV2
VALVE
CONDENSER COIL
OUTDOOR AIR
COMPRESSOR
RDV2
VALVE
CONDENSER COIL
OUTDOOR AIR
COMPRESSOR
C13851
C13852