Lennox SL280UHNX Series Unit Information page 77

Cooling Sequence of Operation
CALL FOR COOLING
1
1ST STAGE COOLING
1
REQUEST RECEIVED
WAIT FOR COMPRESSOR TIMED
OFF DELAY TO EXPIRE
ENERGIZE 1ST STAGE
COOLING CONTACTOR
(COMPRESSOR & FAN)
INDOOR BLOWER 2
SECOND ON DELAY
ENERGIZE INDOOR BLOWER
2
(LOW COOLING MODE)
MAINTAIN INDOOR
(LOW COOLING MODE)
1
2ND STAGE
COOLING
REQUEST?
YES YES
ENERGIZE 2ND STAGE
ENERGIZE INDOOR BLOWER
COOLING CONTACTOR
(HIGH COOLING MODE)
(COMPRESSOR & FAN)
2ND STAGE
COOLING REQUEST
STILL ACTIVE?
NO
DE−ENERGIZE 2ND
STAGE COOLING
CONTACTOR
(COMPRESSOR & FAN)
1ST STAGE
COOLING REQUEST
STILL ACTIVE?
NO
DE−ENERGIZE 1ST
STAGE COOLING
CONTACTOR
(COMPRESSOR & FAN)
DE−ENERGIZE INDOOR
2
BLOWER
1
YES
BLOWER
YES
1ST STAGE
NO COOLING REQUEST
STILL ACTIVE?
2
MAINTAIN INDOOR BLOWER
YES
(HIGH COOLING MODE)
ENERGIZE AND MAINTAIN
YES
INDOOR BLOWER AT
(LOW COOLING MODE)
1 CONTROL WILL NOT RESPOND TO A 2ND STAGE COOLING REQUEST UNLESS A 1ST STAGE
COOLING REQUEST IS ACTIVE.
INDOOR BLOWER LOW COOLING MODE AND HIGH COOLING MODE HAVE SPECIFIC ON, OFF
2
AND SPEED RAMPING PROFILES. THE SPECIFIC PROFILE IS SELECTED USING THE
DIP SWITCHES ON THE CONROL.
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NO