Unit Components - Lennox Elite XP16 Series Installation Instructions Manual

Charging
The XP16 unit is factory-charged with enough HFC-410A
refrigerant to accommodate a 15-foot length of refrigerant
piping. Charge should be checked and adjusted using the
tables provided on the charging procedure sticker on the
unit access panel. Detailed information is given in the
XP16 Installation and Service Procedures manual, which
is available on DaveNet.
System Configuration
IMPORTANT
Some scroll compressor have internal vacuum protector
that will unload scrolls when suction pressure goes
below 20 psig. A hissing sound will be heard when the
compressor is running unloaded. Protector will reset
when low pressure in system is raised above 40 psig. DO
NOT REPLACE COMPRESSOR.
TEST PINS (P1)
DEFROST TERMINATION
PIN SETTINGS (P1)
SENSOR PLUG IN
(COIL AND
AMBIENT
SENSORS) (P4)
DELAY PINS
(P5)
REVERSING VALVE
(O OUT)
PRESSURE SWITCH
CIRCUIT
CONNECTIONS
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Note - Component locations vary by board manufacturer.
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This section addresses:
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Unit components (sensors, temperature switch, pres­
sure switches and demand defrost control)
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Second-stage operation

UNIT COMPONENTS

Demand Defrost Control (A108)
The demand defrost control measures differential temper­
atures to detect when the system is performing poorly be­
cause of ice build-up on the outdoor coil. The controller
self-calibrates when the defrost system starts and after
each system defrost cycle. The demand defrost control's:
components are shown in figure 15.
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Demand defrost control connections, jumpers and
LED locations are shown in figure 15.
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Demand defrost control connections, jumpers and
LED descriptions are listed on table 2.
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Demand defrost control status, fault and lockout LEDs
are listed in table 3.
FIGURE 15
Page 14
LOW AMBIENT
THERMOSTAT PINS
(P3)
DIAGNOSTIC LEDS
(DS1 AND DS2)
24V TERMINAL STRIP
CONNECTIONS (P2)
Demand Defrost
Control (A108)