Lennox SIGNATURE SL280UHV Installation Instructions Manual page 71

Troubleshooting: Cooling Sequence of Operation (Continued)
ENERGIZE 2ND STAGE
COOLING CONTACTOR
(COMPRESSOR & FAN)
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
BLOWER
(LOW COOLING MODE)
1
2ND STAGE
NO
COOLING
REQUEST?
YES YES
ENERGIZE INDOOR BLOWER
(HIGH COOLING MODE)
2ND STAGE
COOLING REQUEST
YES
STILL ACTIVE?
NO
DE−ENERGIZE 2ND
STAGE COOLING
CONTACTOR
(COMPRESSOR & FAN)
1ST STAGE
COOLING REQUEST YES
STILL ACTIVE?
NO
DE−ENERGIZE 1ST
STAGE COOLING
CONTACTOR
1
(COMPRESSOR & FAN)
2
DE−ENERGIZE INDOOR
2
BLOWER
1
YES
YES
1ST STAGE
COOLING REQUEST
STILL ACTIVE?
2
NO
MAINTAIN INDOOR BLOWER
(HIGH COOLING MODE)
ENERGIZE AND MAINTAIN
INDOOR BLOWER AT
(LOW COOLING MODE)
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
AND SPEED RAMPING PROFILES. THE SPECIFIC PROFILE IS SELECTED USING THE
DIP SWITCHES ON THE CONROL.
Page 71