Troubleshooting: Cooling Sequence of Operation
CALL FOR COOLING
5 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
| |||||
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
| |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
| 1st Stage Cooling |
|
|
|
|
|
|
| |||||||||||
|
| Request Received | 1 |
|
|
|
|
|
| |||||||||||
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
| |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
| |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
| |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
| Energize 1st Stage |
|
|
|
|
|
|
|
|
|
| ||||||||
|
| Cooling Contactor |
|
|
|
|
|
|
|
|
|
| ||||||||
|
| (Compressor & Fan) |
|
|
|
|
|
|
|
|
|
| ||||||||
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
| |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
| ||
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
| Indoor Blower On |
|
|
|
|
|
|
|
|
|
|
| ||||||
|
| After 2−second delay |
|
|
|
|
|
|
|
|
|
|
| |||||||
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
| |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
| Energize Indoor Blower |
|
|
|
| 2 |
|
|
|
|
|
| |||||||
|
| (Per Ramping Profile) |
|
|
|
|
|
|
|
|
|
| ||||||||
|
|
|
|
|
|
|
|
|
|
|
|
| ||||||||
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
1 |
|
|
|
|
|
|
|
|
|
|
|
|
|
| YES |
|
| |||
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
| ||||
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
| ||||
|
|
|
|
|
|
|
|
|
|
|
|
| 1st Stage | |||||||
|
|
| 2nd Stage |
|
|
|
| |||||||||||||
|
|
|
|
|
|
| ||||||||||||||
|
|
|
| Cooling |
|
|
|
|
|
|
|
| NO |
| Cooling Request | |||||
|
|
|
|
|
|
|
|
|
|
|
|
| ||||||||
|
|
| Request? |
|
|
|
| Still Active? | ||||||||||||
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
| ||||
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
| |
|
| YES | YES |
|
|
|
|
|
|
|
|
|
|
|
| |||||
|
|
|
|
|
|
|
|
|
|
|
|
|
| |||||||
Energize 2nd Stage Cooling Contactor (Compressor & Fan)
Energize Indoor Blower (High Cooling mode)
2
NO
|
|
|
|
|
|
|
|
2nd Stage |
|
|
|
|
|
| |
|
|
|
| Maintain Indoor Blower | |||
Cooling Request |
| YES |
|
| |||
|
|
| (High Cooling mode) | ||||
|
| ||||||
Still Active? |
|
|
|
| |||
|
|
|
| ||||
|
|
|
|
|
| ||
NO
De−Energize 2nd Stage Cooling Contactor (Compressor & Fan)
|
|
|
|
|
|
|
|
|
|
|
|
1st Stage |
| Energize and |
| ||||||||
Cooling Request |
| YES |
|
|
| Maintain Indoor Blower | at | ||||
|
|
| |||||||||
Still Active? |
|
|
| Low Cooling mode |
| ||||||
|
|
| |||||||||
|
|
|
|
|
|
|
|
|
| ||
|
|
|
|
|
|
|
|
|
|
| |
| NO |
|
|
|
|
|
|
|
| ||
De−Energize 1st Stage Cooling Contactor (Compressor & Fan)
De−Energize Indoor Blower | 2 | |
Per Ramping Profile | ||
|
12nd 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
2Indoor 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.
Page 61
