Toshiba RUAGP Series Original Owner's Manual page 50

(2) Controlling the compressors and pumps of a single module
Control the unit controller that has received operational commands from the module controller as follows.
[Compressors]
The unit controller controls the number
of compressors and operation
frequency in such a way as to make the
leaving water temperature close to the
setpoint. It provides rotation control,
which prioritizes compressors with the
shortest cumulative running hours to
balance running hours among all
compressors. (When two compressors
are necessary, either one of the
downstream circuits (circuits A and B)
and either one of the upstream circuits
(circuits C and D) are operated.)
[Pump]
The module controller provides a flow rate
target to each module. The unit controller
controls the operation frequency to make its
flow rate close to the target.
When operating pump at constant speed:
Operates up to a preset fixed frequency. The
fixed frequency is set during initial start-up.
Flow rate
Maximum
flow rate
Minimum
flow rate
Pump frequency
Maximum
frequency
Minimum
frequency
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Elapsed
time
Elapsed
time