OM 1263 • MICROTECH UNIT CONTROLLER 60 www .DaikinApplied .com
Operator’s Guide
Heat Pump Operating State
Compressor Heating Operation State
Machine – Heat Pump Units Only
This section applies to heat pump units only . When a unit is
configured for heat pump operation the primary source of
heating is provided by operating the compressors in a heating
mode of operation . When this primary heat is unavailable or
at is maximum capacity and more heating is required, any
available supplemental heating is controlled as described
in that section . When this primary heating is enabled the
compressor transitions through the heating states shown in
the following state diagram . Control based on discharge air
temperature (DAT) occurs in the Normal Heating state .
Figure 15: Heating State Diagram
Off to Prestart Pressure Equalization
The Compressor Heating State transitions from OFF to
Prestart Pressure Equalization when the unit enters the
MinDAT or Heating operating state .
Prestart Pressure Equalization to Off
The Compressor Heating State transitions from Prestart
Pressure Equalization to OFF if there is no longer a call for
MinDAT or Heating operation .
Prestart Pressure Equalization to Initialization
The Compressor Heating State transitions from Prestart
Pressure Equalization to initialization after ninety seconds.
Initialization to Normal
The Compressor Heating State transitions from Initialization
to Normal when the initialization sequence is complete. See
Initialization state description in the
Heating State Descriptions” on page 61
.
Initialization to Pumpdown
The Compressor Heating State transitions from Initialization to
Pumpdown if there is no longer a call for MinDAT or Heating
operation .
Initialization to Standby for Restart
The Compressor Heating State transitions from Initialization
to Standby for Restart if one of the Compressor Protection
functions force a transition to Standby for Restart, the inverter
compressor or outdoor fan board requests a transition to
Standby for Restart or if all compressor operation becomes
disabled for any reason .
Normal to Pumpdown
The Compressor Heating State transitions from Normal to
Pumpdown if there is no longer a call for MinDAT or Heating
operation .
Normal to Standby for Restart
The Compressor Heating State transitions from Normal to
Standby for Restart if one of the Compressor Protection
functions force a transition to Standby for Restart, the inverter
compressor or outdoor fan board requests a transition to
Standby for Restart or if all compressor operation becomes
disabled for any reason .
Pumpdown to Standby for Restart
The Compressor Heating State transitions from Pumpdown
to Standby for Restart if one of the Compressor Protection
functions force a transition to Standby for Restart, the inverter
compressor or outdoor fan board requests a transition to
Standby for Restart or if all compressor operation becomes
disabled for any reason .
Pumpdown to Initialization
The Compressor Heating State transitions from Pumpdown
to initialization if there is a call for cooling MinDAT or Heating
operation .
Standby for Restart to Off
The Compressor Heating State transitions from Standby for
Restart to OFF after the heating stage timer expires .
Summary of Contents for MicroTech III DPS
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