Lennox XP21 Series Installation Instructions Manual page 39

DISCHARGE
Y1 DEMAND
SENSOR
(RT28)*
COMPRESSOR
CONTACTOR
DE−ENERGIZED
OPEN
COMPRESSOR
ANTI−SHORT
CYCLE TIMER
BEGINS
INCREMENT
5−STRIKE
COUNTER
LED ALERT
CODE / OR
MODERATE
ALERT 414
DISPLAYED
ANTI−SHORT
CYCLE TIMER
ENDS
DISCHARGE
SENSOR (RT28)
YES
IS AT OR
BELOW 225ºF
COMPRESSOR
CONTACTOR
ENERGIZED
NO
WAITING FOR
TEMPERATURE
DROP TO OR
BELOW 225ºF
Figure 31. High Discharge Temperature Sensor (RT28) Sequence of Operation
CLOSED
HIGH
PRESSURE
OPEN
SWITCH (S4)
1
If 5−strike counter has four or less strikes when Y1 demand is
terminated or satisfied, the strike counter will reset to zero. In a icomfort
®
Touch thermostat enabled setup, the thermostat will terminate demand
when the compressor contactor is de−energized. If demand is satisfied
when alarm is not active, the 5−strike counter will reset.
2
Lockouts can be reset by either cycling power off to the heat pump
control's (A175) R terminal, or placing a jumper on the field test pins
(E33) between 1 to 2 seconds.
5−STRIKE
COUNTER
REACHES 5
WITHIN A SINGLE
1
Y1 DEMAND
DISCHARGE
SENSOR (RT28)
LOCKOUT
LED ALERT
CODE / OR
CRITICAL
ALERT 415
CLEARED
Page 39
*
If temperature is at or above 279ºF.
COMPRESSOR
CONTACTOR
ENERGIZED
CLOSED
SERVICE
REQUIRED
LED ALERT
CODE / OR
MODERATE
ALERT 414
CLEARED
2
NORMAL
OPERATION
XP21 SERIES