Carrier 48TC 17 Series, Service And Maintenance Instructions, Page: 13 / 96

13
Operating Sequences
The Humidi −− MiZer system provides three sub − modes
of operation: Normal Cooling (see Fig. 17), Subcooling
Reheat1 (see Fig. 18) and Hot Gas Reheat2 (see Fig. 19).
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 only a single cooling demand (thermostat
Y1 alone or with thermostat Y2), one or both circuits will
operate in Reheat2 mode. Both solenoids are energized in
both circuits. See Fig. 18, Hot Gas Reheat Schematic for
system refrigerant flow.
When there is both cooling demand (thermostat Y1
demand) and dehumidification demand, circuit 1 will
operate in Reheat1 mode (Subcooling, Fig. 17) and circuit
will operated in Reheat2 mode (Reheat, Fig. 18). In
Reheat1 mode, the 3 −− way solenoid valve is energized,
opening the reheat coil to the refrigeration flow path
providing sub
−− cooling to the liquid before it enters the
TXV.
CONDENSER COIL
HUMIDI-MIZER COIL
EVAPORATOR COIL
COMPRESSOR
OUTDOOR AIR
INDOOR AIR
RH2.x
VALVE
RH1.x
VALVE
TXV
VALVE
= CLOSED VALVE
= OPEN VALVE
= 3-WAY VALVE
N/A
C07122A
Fig. 17 − Normal Cooling Mode – Humidi − MiZer R System
CONDENSER COIL
HUMIDI-MIZER COIL
EVAPORATOR COIL
COMPRESSOR
OUTDOOR AIR
INDOOR AIR
RH2.x
VALVE
RH1.x
VALVE
TXV
VALVE
= CLOSED VALVE
= OPEN VALVE
= 3-WAY VALVE
C07123A
Fig. 18 − Subcooling Mode (Reheat 1) – Humidi − MiZer R System