Daikin Pathfinder AWV Installation, Operation And Maintenance Manual page 71

Operation – Closed State
The EXV position command should be 0% any time the EXV is
in the closed state. The 0% position command also causes the
EVD driver to re-initialize the valve to the zero position. After
one minute, the EXV position command should be set to 25%
open and remain there until the state changes.
Operation – Purge State
In the Purge state, the economizer EXV position is 0%.
Operation – Superheat Control State
In the Superheat control state, the EXV will be positioned to
control economizer gas superheat.
Liquid Injection Solenoid Valve
As an option, the chiller can be equipped with liquid injection
on the compressors. When configured with this option, the
Liquid Injection Configuration setting should be set to Yes and
the liquid injection solenoid valve outputs can be activated.
Liquid injection solenoid valve output is activated if both of the
following are true:
• Circuit state is Run
• Discharge Temperature > Liquid Injection Activation set
point
Liquid injection solenoid valve output will be turned off if either
of the following are true:
• Discharge Temperature < Liquid Injection Activation set
point - 15°C
• Circuit state is no longer Run
Liquid Line Solenoid Valve
As an option, the chiller can be equipped with liquid line
solenoid valves. When configured with this option, the Liquid
Line Solenoid Valve Configuration setting should be set to Yes.
If the chiller is configured with liquid line solenoid valves, the
liquid line solenoid valve output should be activated when the
circuit enters the Preopen state and remain on during the Start
and Run states. The output should be turned off 10 seconds
after the circuit enters the Pumpdown state or when the circuit
state is Off.
Circuit Capacity Overrides
The following conditions override automatic capacity control
as described. These overrides keep the circuit from entering a
condition in which it is not designed to run.
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High Water Temperature Capacity Limit
If the evaporator LWT is 25°C (77°F) or higher, the circuit
capacity will be limited. If circuit capacity resulting from the
next compressor speed increase is 81.5% or more, the circuit
cannot increase in capacity.
If the circuit capacity is higher than 81.5%, the circuit will
reduce capacity until it is at 81.5% or lower.
Once this limit is triggered, it will be in effect until evaporator
LWT is less than 25°C (77°F) for at least one minute.
71 IOM 1242-8 • PATHFINDER
Circuit Functions
MODEL AWV CHILLERS
®