Lennox LDT Series Information page 20

6-Filter Drier (all units)
Units have a filter drier located in the liquid line of each
refrigerant circuit at the exit of each condenser coil. The
drier removes contaminants and moisture from the system.
7-Condenser Fans
B4, B5, B21, B22, B23 and B24 (All Units)
See SPECIFICATIONS tables at the front of this manual for
specifications of condenser fans used in all units. All
condenser fans used have single-phase motors. The fan
assembly may be removed for servicing and cleaning.
8-Reversing Valve
A refrigerant reversing valve with a 24 volt solenoid coil is
used to reverse refrigerant flow during unit operation in all
LDT/LHT units. The reversing valve is connected in the
vapor line of the refrigerant circuit. The reversing valve coil
is energized during cooling demand and during defrost.
Reversing valve L1 & L2 are controlled by the A55 Control
board in response to a cooling demand or by defrost.
9-Temperature Thermistor
Units are equipped with four factory-installed thermistors
(RT46 - RT49) located on different points on the refrigerant
circuit.
The thermistors provide the Unit Controller with constant
temperature readings of four specific locations on the
refrigeration circuit. These temperatures are used as
feedback in certain modes of unit operation. In addition, the
Unit Controller uses these temperatures to initiate alarms
such as loss of outdoor or indoor coil airflow and loss of
charge.
Each thermistor must be specifically placed for proper unit
operation and to initiate valid alarms. See figure 9 for indoor
coil location and figure 10 for outdoor coil location.
THERMISTOR LOCATION
INDOOR COIL
(RT46, RT47)
Note - 156H units
do not use bypass
BLUE
RT47
YELLOW
RT46
FIGURE 9
Page 20
assemblies
RT46 / RT47