Circuit Availability; Oil Sump Check; Circuit States - Daikin Pathfinder AWV Series Installation, Operation And Maintenance Manual

Circuit Availability

A circuit is available to start if the following conditions are true:
• Circuit switch input is on
• No manual reset circuit fault alarms are active
• Circuit Mode set point is set to Enable
• BAS Circuit Mode set point is set to Auto
• No cycle timers are active
• Oil Sump Check = Ready

Oil Sump Check

Oil sump check is to make sure that oil in the sump is of
sufficient quality prior to starting the compressor.
Oil sump check is set to Ready when
Discharge Temperature > Saturated Oil Temperature + 5°C
Oil sump check is set to Not Ready when
Discharge Temperature < Saturated Oil Temperature + 4.5°C

Circuit States

There are five distinct states of control for the circuit as shown.
Figure 62: Circuit State Transitions
POWER
OFF
ON
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T1
PREOPEN
T9
T2
T7 T8
START
T3
T6
RUN
T4
T5
PUMPDOWN
T1 – Off to Preopen - All of the following are required:
• Circuit is available to start per the previous section
• Adequate pressure in the evaporator and condenser (see
No Pressure At Start Alarm)
• Unit capacity control logic requires the circuit to start
T2 – Preopen to Start
Evaporator EXV completes preopen operation.
T3 – Start to Run
Compressor speed ≥ 19Hz for at least 30 seconds
T4 – Run to Pumpdown - Any of the following are required:
• Unit capacity control logic requires this circuit to stop
• Unit state is pumpdown
• A pumpdown alarm occurs on the circuit
• Circuit switch input is off
• Control Source = Network and BAS Circuit Mode = Off
T5 – Pumpdown to Off - Any of the following are required:
• Evaporator Pressure drops below Pumpdown Target
Value
• Circuit state has been pump down for longer than the
Pumpdown Time Limit set point
• Unit state is Off
• Rapid stop alarm occurs on the circuit
T6 – Run to Off - Any of the following are required:
• Unit state is Off
• Rapid stop alarm occurs on the circuit
T7 – Start to Off - Any of the following are required:
• Unit state is Off
• Rapid stop alarm occurs on the circuit
T8 – Start to Pumpdown - Any of the following are required:
• Unit capacity control logic requires this circuit to stop
• Unit state is pumpdown
• A pumpdown alarm occurs on the circuit
• Circuit switch is open
• Control Source = Network and BAS Circuit Mode = Off
T9 – Preopen to Off - Any of the following are required:
• Unit state is Off
• A rapid stop alarm occurs on the circuit
• A pumpdown alarm occurs on the circuit
• Circuit switch input is off
• Control Source = Network and BAS Circuit Mode = Offf
59 IOM 1242-2 • PATHFINDER
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IrCuIT unCTIons
MODEL AWV CHILLERS
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