Lennox Signature XP21 Series Installation And Service Procedure page 79

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
DISCHARGE
SENSOR (RT28)
YES
IS AT OR
BELOW 225ºF
COMPRESSOR
CONTACTOR
ENERGIZED
NO
WAITING FOR
TEMPERATURE
DROP TO OR
BELOW 225ºF
Figure 45. High Discharge Temperature Sensor (RT28) Sequence of Operation (All Versions)
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 icomfortt 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.
WITHIN A SINGLE
1
SENSOR (RT28)
ENDS
Page 79
*
If temperature is at or above 279ºF.
COMPRESSOR
CONTACTOR
ENERGIZED
CLOSED
5−STRIKE
COUNTER
REACHES 5
Y1 DEMAND
DISCHARGE
LOCKOUT
LED ALERT
CODE / OR
CRITICAL
REQUIRED
ALERT 415
CLEARED
LED ALERT
CODE / OR
MODERATE
ALERT 414
CLEARED
SERVICE
2
NORMAL
OPERATION
XP21