Lennox TPA036H4N4 Installation Instructions Manual page 29

Table 8. Demand Defrost Control (A108) Inputs, Outputs and Configurable Settings
Control Control Label or
Location Description
P1 TEST
P1 50, 70, 90, 100
W1
C
L
P2
R
Y2
O
Y1
P3 55, 50, 45, 40
DIS−YEL
P4
AMB−BLACK
COIL−BROWN
P5 DELAY
P6 TST, PS DF, C, R, O, Y1, Y2
DS1 RED LED
DS2 GREEN LED
FAN TWO CONNECTORS
O OUT O OUT
LO−PS LO−PS
Y2 OUT Y2 OUT
Y1 OUT Y1 OUT
HS−PS HS−PS
L L
24V 24V
Purpose
Test Mode
Defrost Temperature Termina-
tion Shunt (Jumper) Pins
24VAC Thermostat Input /
Output
24VAC Common
Thermostat Service Light
24VAC
Thermostat Input
Thermostat Input
Thermostat Input
Low Ambient Thermostat Pins
Coil Sensor
Ambient Sensor
Discharge Sensor
Delay Mode
Factory Test Connectors
Diagnostic LED
Condenser Fan Operation
24 VAC output
Low−Pressure Switch
24 VAC Output
24 VAC Common Output
High−Pressure Switch
Line output
24 Volt output
Page 29
Function
See Test Mode on page 35 for further details.
The demand defrost control has valid selections which are: 50, 70,
90, and 100°F (10, 21, 32 and 38°C). The shunt termination pin is
factory set at 50°F (10°C). If the temperature shunt is not installed,
the default termination temperature is 90°F (32°C).
24VAC input/output from indoor thermostat to indoor unit.
24VAC common
Thermostat service light connection.
24VAC
Controls the second stage operation of the unit.
Reversing valve solenoid.
Controls the operation of the unit.
Provides selection of the Y2 compressor lock−in temperature. Val-
id options are 40, 45, 50 and 55 degrees Fahrenheit.
(P4−5) Ground connection for outdoor coil temperature sensor.
(P4−6) Connection for outdoor coil temperature sensor.
(P4−3) Ground connection for outdoor ambient temperature sen-
sor.
(P4−4) Connection for outdoor ambient temperature sensor.
No discharge sensor is used; replaced by 10K resistor.
The demand defrost control has a field−selectable function to
reduce occasional sounds that may occur while the unit is cycling
in and out of the defrost mode. When a jumper is installed on the
DELAY pins, the compressor will be cycled off for 30 seconds
going in and out of the defrost mode. Units are shipped with jumper
installed on DELAY pins.
−
NOTE The 30 second off cycle is NOT functional when
jumpering the TEST pins on P1.
No field use.
Valid states for demand defrost control's two LEDs are OFF, ON
and FLASHING which indicate diagnostics conditions that are de-
scribed in tables 9 and 10.
These two connections provide power for the condenser fan.
24 VAC output connection for reversing valve.
When the low pressure switch trips, the demand defrost control
will cycle off the compressor, and the strike counter in the demand
defrost control will count one strike. The low pressure switch is
ignored under the following conditions:
S
during the defrost cycle and 90 seconds after the termination
of defrost
S
when the average ambient sensor temperature is below 0°F
(−18°C)
S
for 90 seconds following the start up of the compressor
S
during TEST mode
24 VAC output for second stage compressor solenoid.
24 VAC common output, switched for enabling compressor
contactor.
When the high pressure switch trips, the demand defrost control
will cycle off the compressor, and the strike counter in the demand
defrost control will count one strike.
24VAC service light output.
24VAC typically used to supply power to the Lennox System
Operation Monitor (LSOM)
TPA*H4 SERIES