13
Humidi--MiZer System Components
The Humidi--MiZer uses the standard unit compressor(s),
evaporator coil and Round Tube--Plate Fin (RTPF)
condenser coil. Additional refrigeration system hardware
includes a subcooler/reheat coil and solenoid valves. On
50HC models, the evaporator coil includes a TXV as a
standard feature. Units with Humidi--MiZer FIOP also
include a factory--installed head pressure control system
(Motormaster I) to provide proper liquid pressure during
reheat modes. Unique controls include a Reheat Relay
Board (RHB), evaporator coil freezestat, secondary low
pressure switch and a low outdoor temperature lockout
switch (LTLO). Units with two refrigeration circuits
include a solenoid valve, TXV, freezestat and low pressure
switch for each circuit. See Fig. 15.
RH1.A
RH2.A
RH1.B
RH2.B
C08057
Fig. 15 -- Humidi--MiZer Valve Locations
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.
3--Way Solenoid Valve
Hot Gas Bypass Solenoid Valve
Relay Reheat Board (RHB)
Evaporator Freeze Protection Thermostat
Low Outdoor Temperature Lockout Switch
Secondary Low Pressure Switch
Head Pressure Control
Operating Sequences
The Humidi--MiZer system provides three sub--modes of
operation: Normal Cooling (see Fig. 16), Subcooling
Reheat1 (see Fig. 17) and Hot Gas Reheat2 (see Fig. 18).
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.
48H
C
Summary of Contents for 48HC D17 Series
Page 77: ...77 APPENDIX IV WIRING DIAGRAMS C12616 Fig 77 48HC D17 D28 Power Diagram 208 230 3 60 48HC...
Page 78: ...78 APPENDIX IV WIRING DIAGRAMS C12617 Fig 78 48HC D17 D28 Power Diagram 460 3 60 48HC...
Page 79: ...79 APPENDIX IV WIRING DIAGRAMS C12618 Fig 79 48HC D17 D28 Power Diagram 575 3 60 48HC...
Page 86: ...86 APPENDIX IV WIRING DIAGRAMS C13767 Fig 86 RTU OPEN Wiring Diagram 48HC...
Page 87: ...87 APPENDIX IV WIRING DIAGRAMS C13768 Fig 87 RTU OPEN Wiring Diagram with Humidi MiZer 48HC...
