Main Functions - Toshiba RUAGP Series Original Owner's Manual

1. Automatic control functions
Cooling and heating operations
This heat pump starts a refrigeration cycle using compressors and optimizes the cycle to produce
chilled or warm water by controlling the opening of electric expansion valves and the speed of fans. It
adjusts the number of compressors to be activated and their operation frequency to make the leaving
water temperature close to a setpoint.
(Note)
In a low outdoor air temperature or snowy environment, it takes some time for the leaving water
temperature to reach a setpoint after a heating operation starts.
Rotation control
The module controller provides rotation control, which preferentially runs the modules with the least
cumulative run hours to evenly distribute operations across all modules. Additionally, each module
preferentially runs the compressors with the least cumulative run hours to evenly distribute operations
across all its compressors.
Flow rate control
The module controller calculates the flow rate required by the load side and adjusts the number of
inverter pumps to be activated in each module and their operation frequency.
(Note)
Some systems do not support flow rate control based on the flow rate requirement of the load side. For
these systems, the module controller must be configured for fixed-frequency operation.
Freeze protection operation
When compressors are not running, the fracturing of water heat exchangers, pumps and other devices
may occur due to a drop in outdoor air temperature. To prevent this problem, the module controller
monitors the water entering/leaving and evaporation temperatures to control the starting and stopping
of internal and external pumps.
Group control over external pumps
The heat pump and external water pumps are linked together.
(Note)
Before activating group control of external pumps, ensure that water is present in pipes for pipe
protection. Ensure that the water circuit is not isolated by the solenoid valve.
Distributed defrosting control
In the Heating mode, the unit controller determines frost formation on the air heat exchanger in each
circuit and performs defrosting. The four circuits in a given module perform a defrost operation
alternately to reduce a drop in warm water temperature during defrosting.
(Note)
The module controller does not prohibit simultaneous defrosting by multiple modules. Therefore,
multiple modules can perform a defrost operation at the same time. For 60HP (Powerful heating type),
however, there is an upper limit on the number of modules to be defrosted at the same time, and it is
difficult for the warm water leaving temperature during defrosting to decrease. In addition, 60HP
(Powerful heating type) determines the frosted state including the relative humidity.

Main Functions

=> See page 47.
=> See page 47.
=> See page 49.
=> See the Installation Manual.
=> See page 48.
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