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ARTC-SVX013A-EN
Compressor Staging Valve Control
All compressors Staging Valves controls can be accessed
from compressors screen Main Menu →Comp button →
Staging button. Controls are available for Tech level HMI
users and above.
Each Staging Valve controls consist of two components:
1. Mode selector
2. Valve status light
Figure 28. Staging valves control screen
As per control options, each Staging Valve can be in one of
the modes:
1. Off – staging valve is always off regardless of other
conditions.
2. On – staging valve is forced on. Used mostly for
troubleshooting or maintenance purposes.
3. Auto – staging valve is controlled automatically as
compressor cycles through its states.
Compressor Staging Priority
Compressor staging priority defines the order by which the
compressors are staged up. By default, this priority is by
runtime, but a Tech-Level user can change this priority with
the following options:
• Runtime (default selection) – compares the runtimes of
the compressors:
– On stage up – the lowest runtime is started.
– On stage down – the highest runtime is stopped.
• Default – Default as a named option refers to the built
order of the chiller. For example, compressor labelled
Compressor #1 is first on and last off; Compressor
labelled Compressor #2 is second on and second last
off.
• User – using the following pop-up, the user can define
the priority. Once the selections have been made, the
user must commit the changes. There can be no
duplicates and, user cannot define a priority to
compressor that is not on part of the chiller. Any errors
to the selection will prevent commit function with
suitable messages to user.
•
Optional Functionalities
The following table lists the Optional Functionalities of this
control system:
Table 16. Chiller control system Optional Functionalities list
Function Brief Access Level
Free Cooling
Monitor and Control fan banks (when in free cooling) and free cooling modulation valve
functions
Tech
Pump and Plant controls Monitor and Control evaporator and condenser pumps functions
Tech
Data Logging Displays chillers / compressors key data logged to CSV files
Admin
Master / Slave
Monitor and Control multiple chillers primary/secondary functions
Tech
Controller option
Select the model of Main Chiller PLC Admin
Economizer
Monitor and Control compressors economizers functions
Tech
Hot Gas Bypass Valve Monitor and Control compressors Hot Gas Bypass functions
Tech
Low-Lift Application
Allows chiller to operate at pressure ratios less than 1.5. Adds a refrigerant pump to
push liquid refrigerant to compressor motor cooling ports.
Tech
Operating Procedures
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