Daikin DPS - Mechanical Cooling; Compressor Cooling Operation State

Mechanical Cooling
(See page 106 for more information)
The unit enters the mechanical cooling operating state when
cooling is required and the economizer is disabled, not present,
or already fully open.
If the unit is congured for Zone Temperature Control the
transition to Mechanical cooling will occur if all the following are
true:
• The control temperature rises above the occupied cooling
set point by more that ½ the occupied cooling deadband
• The discharge air temperature is greater than the Min
DAT limit by more than ½ the DAT heating deadband.
This will prevent more cold air from being brought in when
the DAT is already cold
• The economizer operation is disabled or not present
• Mechanical cooling is enabled
If the unit is congured for Discharge Air Temperature Control
the transition to Mechanical cooling will occur if all the following
are true:
• The control temperature rises above the occupied cooling
set point by more that ½ the occupied cooling deadband
• The discharge air temperature is greater than the DAT
cooling set point by more than ½ the DAT cooling
deadband
• Post heat operation is complete
• Economizer operation is disabled
• Mechanical cooling is enabled
Compressor Cooling Operation
State
(See page 106 for more information)
When the unit enters the Cooling operating state,
dehumidication operation becomes active or compressors are
turned On via the manual control function, compressor operation
transitions through the compressor cooling states shown in
the following state diagram. Control based on discharge air
temperature [DAT] occurs in the Normal Cooling state.
Figure 15: Cooling State Diagram
Off to Prestart Pressure Equalization
The Compressor Cooling State transitions from Off to Prestart
Pressure Equalization when the unit enters the Cooling
operating state or the Dehumidication function becomes
active.
Prestart Pressure Equalization to Off
The Compressor Cooling State transitions from Prestart
Pressure Equalization to Off if there is no longer a call for
cooling or dehumidication operation.
Prestart Pressure Equalization to
Initialization
The Compressor Cooling State transitions from Prestart
Pressure Equalization to initialization after thirty seconds.
Initialization to Normal
The Compressor Cooling State transitions from Initialization
to Normal when the initialization sequence is complete. See
Initialization state description in the Inverter Compressor
Cooling State Descriptions section.
Initialization to Pumpdown
The Compressor Cooling State transitions from Initialization
to Pumpdown if there is no longer a call for cooling or
dehumidication operation.
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