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Troubleshooting: Cooling Sequence of Operation
CALL FOR COOLING
1st Stage Cooling
Request Received
Energize 1st Stage
Cooling Contactor
(Compressor & Fan)
2nd Stage
Cooling
Request?
YES
2nd Stage
Cooling Request
Still Active?
De−Energize 1st
Stage Cooling
Contactor
(Compressor & Fan)
YES
1st Stage
Cooling Request
Still Active?
NO
YES
YES
Energize 2nd Stage
Cooling Contactor
(Compressor & Fan)
1st Stage
Cooling Request
Still Active?
De−Energize 2nd
Stage Cooling
Contactor
(Compressor & Fan)
Energize and
Low Cooling mode
(High Cooling mode)
(High Cooling mode)
Per Ramping Profile
NO
NO
YES
NO
5
1
2
1
2
2
2
1
Indoor Blower On
After 2−second delay
Energize Indoor Blower
(Per Ramping Profile)
Energize Indoor Blower
Maintain Indoor Blower
Maintain Indoor Blower at
De−Energize Indoor Blower
2nd stage cooling operation requires a 2−stage thermostat, a 2−stage cooling system and
on−board link W915 must be be cut. The control will not respond to a 2nd stage cooling
request unless a 1st stage cooling request is active
Indoor blower cooling mode and high cooling mode have a specific ON, OFF and speed
ramping profiles. The specific profile is selected using the DIP switches on the control.
