OM 1263 • MICROTECH UNIT CONTROLLER 48 www .DaikinApplied .com
Operator’s Guide
Start Up Operating State
When a unit is commanded to start it will always enter the
Startup operating state from the Off operating state. The unit
remains in the Startup operating state for an adjustable time
period (default 180 seconds) before entering the Recirculating
operating state .
During the Start up operating state the fans remain off, the
outdoor air dampers are driven closed, and variable speed
supply air fan’s remain at 0% . Cooling and heating are
disabled, except for 100% OA heating start sequences.
Heating
The unit enters the Heating operating state when the control
calls for heat . This is for heat pumps only .
Mechanical Cooling
The unit enters the mechanical cooling operating state when
cooling is called for by the third-party controller .
Figure 14: 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 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 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, page 51 .
Initialization to Pumpdown
The Compressor Cooling State transitions from Initialization to
Pumpdown if there is no longer a call for cooling operation .