Electrical Maintenance
56
6. Repeat test procedure several times to be sure
the setting is correct.
7. Remove the test equipment. Install wire on
switch terminal and air sensing tubes on air
switch. The BLACK hose from the high
pressure or air inlet side of the evaporator coil
goes on the hose fitting on the side of the air
switch stamped BLACK. The CLEAR hose
from the low pressure or air outlet side of the
evaporator coil goes on the hose fitting on the
side of the air switch stamped CLEAR.
NOTE: Route hoses for continuous slope to
avoid condensate traps.
If too much frost continues to accumulate before
defrost, decrease the pressure setting. Turn the
adjustment screw counterclockwise.
If defrost action occurs with too little frost
accumulation, increase the pressure setting. Turn
the adjustment screw clockwise.
High Capacity TherMax
TM
Heating System
The high capacity heating system increases the
capacity of the Heat mode by making more
refrigerant available for use in the Heat mode.
This is accomplished by adding an additional
solenoid (TherMax
TM
solenoid) to the
refrigeration system which opens during the
beginning of the Heat mode to move the liquid
refrigerant from the condenser to the accumulator
where it can be used in the Heat mode. The
sequence of operation for the improved heating
system is from the Cool mode to the Heat mode
with Refrigerant Transfer mode to the Heat mode.
The Heat mode to Cool mode operation is the
same as in the past. The bypass check valve, and
the condenser check valve have been eliminated
from the TherMax
TM
heating system.
The components that have been added to the
system are:
•
the TherMax
TM
solenoid
•
the TherMax
TM
solenoid line
•
the receiver outlet check valve
The TherMax
TM
solenoid controls the flow of
refrigerant through the TherMax
TM
solenoid line.
The TherMax
TM
solenoid line goes from the liquid
line just past the receiver outlet check valve to the
accumulator inlet. The receiver outlet check valve
is located in the liquid line near the drier/receiver
outlet. This check valve prevents refrigerant from
migrating back into the receiver tank and
condenser during the Heat mode.
Cool Mode
The Cool mode has not been changed in the
TherMax
TM
heating system. The TherMax
TM
solenoid, which is normally closed, is
de-energized during the Cool mode. The
TherMax
TM
solenoid separates the high side from
the low side. When the TherMax
TM
solenoid is
closed, it does not allow liquid refrigerant to flow
from the liquid line, through the TherMax
TM
solenoid line, to the accumulator.
Heat/Condenser Evacuation Mode
The unit will run in the Condenser Evacuation
mode for two minutes before entering the Heat
mode. This is accomplished by opening
(energizing) the TherMax
TM
solenoid while the
unit is running in cool. The pressure difference
between the high pressure in the condenser and
the low pressure in the accumulator drives much
of the refrigerant out of the condenser and
receiver into the accumulator. The refrigerant is
then available for improved heating capacity. The
unit is placed in the Heat mode by opening
(energizing) the hot gas solenoid and closing
(energizing) the condenser inlet solenoid. The
TherMax
TM
solenoid remains open while the unit
is in the Heat mode. The receiver outlet check
valve prevents the migration of refrigerant back
into the receiver tank and condenser.
Summary of Contents for 919180
Page 4: ...4...
Page 10: ...Table of Contents 10...
Page 32: ...Unit Description 32 Unit Photographs Figure 3 Front View Figure 4 Back View AJA584 AJA585...
Page 33: ...Unit Description 33 Figure 5 Left Side View Figure 6 Right Side View AJA586 AJA58...
Page 35: ...Unit Description 35 Figure 8 North American Power Receptacle Box AJA58...
Page 38: ...Unit Description 38...
Page 58: ...Electrical Maintenance 58...
Page 66: ...Engine Maintenance 66 Figure 37 Fuel and Oil System Components...
Page 84: ...Engine Maintenance 84...
Page 96: ...Refrigeration Maintenance 96...
Page 118: ...Hilliard Clutch Maintenance 118...
Page 136: ...Cycle Diagrams 136...
Page 140: ...Wiring and Schematic Diagrams Index 140...
Page 141: ...141 Truck S Model SR 30 Schematic Diagram Page 1 of 2...
Page 142: ...142 Truck S Model SR 30 Schematic Diagram Page 2 of 2...
Page 143: ...143 Truck S Model 30 Units with P T Wiring Diagram Page 1 of 2...
Page 144: ...144 Truck S Model 30 Units with P T Wiring Diagram Page 2 of 2...
Page 145: ...145 Truck S Model 50 Schematic Diagram Page 1 of 2...
Page 146: ...146 Truck S Model 50 Schematic Diagram Page 2 of 2...
Page 147: ...147 Truck S Model 50 Units with P T Wiring Diagram Page 1 of 2...
Page 148: ...148 Truck S Model 50 Units with P T Wiring Diagram Page 2 of 2...