Lennox XC20-036-230-01 Installation And Service Procedure page 55

PRESSURE
Y1 DEMAND
SWITCH (S4)
CONTACTOR
DE-ENERGIZED
OPEN
ANTI-SHORT
CYCLE TIMER
BEGINS
INCREMENT
5-STRIKE
COUNTER
LED ALERT
CODE / OR
MODERATE
ALERT 412
DISPLAYED
ANTI-SHORT
CYCLE TIMER
ENDS
HIGH
PRESSURE
SWITCH (S4)
SERVICE
2
REQUIRED
WAITING FOR
PRESSURE
OPEN
SWITCH TO
CLOSE
Figure 32. High Pressure Switch (S4) Sequence of Operation (All Versions)
HIGH
CLOSED
HIGH
PRESSURE
OPEN
SWITCH (S4)
1. The thermostat will terminate demand when the 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 cycling power off to the outdoor control's
(A175) R terminal.
REACHES 5
WITHIN A SINGLE
1
Y1 DEMAND
SWITCH (S4)
CLOSED
CLOSED
TOP CAP
SWITCH (S173)
CLOSED
5-STRIKE
COUNTER
HIGH
PRESSURE
LOCKOUT
LED ALERT
CODE / OR
CRITICAL
REQUIRED
ALERT 413
CLEARED
LED ALERT
CODE / OR
MODERATE
ALERT 412
DISPLAYED
55
CONTACTOR
CLOSED
ENERGIZED
SERVICE
2
NORMAL
OPERATION
XC20