Daikin Trailblazer AGZ030E-070E, Инструкция по установке, эксплуатации и обслуживанию

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IOM 1207-6 • TRAILBLAZER
®
MODEL AGZ CHILLERS 100 www.DaikinApplied.com
Circuit Functions
other than 0vdc (meaning the connected fans should run), but
any time both VFD’s are to be running the speed signals will
be the same (there is no independent speed control on the two
VFD’s within a circuit). The speed will normally be controlled
between the minimum and maximum speed set points using a
PID loop.
The optional VFD fan control will allow unit operation down
to a minimum of -10°F (-23°C). For a discussion of the VFD
controller and operation - See Fan VFD Controller on page
110 .
VFD State
The VFD speed signals should always be 0 when the fan stage
is 0.
When the condenser fan staging requires the fans connected
to a VFD to run, the VFD speed signal should be enabled and
control the speed as needed.
Stage Up Compensation
In order to create a smoother transition when another fan is
staged on, the VFD speed compensates by slowing down
initially. This is accomplished by adding the new fan stage up
deadband to the VFD target. The higher target causes the
VFD logic to decrease fan speed. Then, every 2 seconds,
0.1°C (0.18°F) is subtracted from the VFD target until it is
equal to the saturated condenser temperature target set point.
Sound Reduction Operation
When Sound Reduction is active, the maximum speed of the
VFD’s will be limited to the Sound Reduction fan speed limit set
point value... See Sound Reduction on page 92 .
High IPLV Mode
When the High IPLV Mode setting is ‘On’ and one compressor
is running on the unit, the condenser target setting for the
running circuit may be overridden. In this case, rather than use
the condenser target setting for 33% or 50% (depending on
number of compressors), the condenser target will be forced to
the value of the IPLV Condenser Target set point.
In addition, when high IPLV mode is active the calculation for
the minimum allowed condenser target (based on LWT) will
be changed. The minimum value will be changed from 23.9°C
(75°F) to the value of the IPLV Condenser Target set point.
No other changes to the operation are made when High IPLV
mode is on.
EXV Control
Control States
EXV control will always be in one of two states: Closed or
Superheat Control.
Transitions between these states are shown in
Figure 78.
Figure 78: EXV Control Transitions
T1 – Closed to Superheat Control
• Circuit state is preopen
T2 – Superheat Control to Closed
• Circuit state is off or pumpdown
Closed State Operation
When the EXV is in the Closed state the position command will
be 0 and the EXV control state display will show ‘Closed’.
Superheat Control State Operation
While in superheat control, the EXV controls suction superheat.
A PID loop will be used to control the suction superheat to
the target value. The EXV response is faster when the SSH
is lower than 1.67°C (3°F) or higher than the SSH
1.67°C (3°F). Normally during superheat control the EXV
control state display will show ‘Superheat’.
The EXV should also prevent the evaporator pressure from
exceeding the Maximum Evaporator Pressure set point. This
is done by using another PID function to control evaporator
pressure to the maximum evaporator pressure. The EXV
position should be the lesser position output from the two PID
functions. If the EXV position is being limited due to exceeding
the maximum evaporator pressure, then the EXV control state
display will show ‘MaxEvapPr’.
Superheat Target
The suction superheat target is selected per the set points
depending on what capacity the circuit is running at.
• If the circuit has two compressors and one is running, the
value used is the SSH Target at 50% set point. If both
compressors are running the SSH Target at 100% set
point is used.
• If the circuit has three compressors and one is running,
the value used is the SSH Target at 33% set point. If
either two or three are running the SSH Target at
66/100% set point is used.
If no compressors are running the target is set to the set point
used when one compressor is running (this applies during EXV
preopen).