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3. Compressor Control
3. Compressor Control
(5) Forced Stopping of Compressor
Once a compressor stops, it will not start for a period of 3 minutes (3-minute forced OFF).
However, this is not applied when the compressor was forced to stop as the result of a special control
operation. (Start control, Defrost control, Refrigerant oil recovery control, etc.)
(6) Horsepower Control (Roadmap Control)
1
Horsepower control (start & stop of compressor and increase & decrease of inverter frequency) are
controlled according to the numerical value of the pressure sensor installed at the outdoor unit and the
temperature sensor installed at the indoor unit heat exchanger.
* The pressure detected by the pressure sensor is converted to the saturated temperature.
There are two types of controls; one is the pressure detected by the pressure sensor and the other is
detected by the saturated temperature.
High pressure saturated temperature is converted from values detected by the high pressure sensor.
Low pressure saturated temperature is converted from values detected by the low pressure sensor.
2
This control is performed every 30 seconds.
3
When cooling operation, evaporation temperature (= antifreeze control) and condensation temperature
(= high pressure prevention control) are applied.
When heating operation, condensation temperature (= high pressure prevention control) is applied.
Definition of evaporation temperature (Te)
Lowest temperature of all indoor units' evaporation temperature (E1, E3) in the system including the
stopped indoor units
Definition of condensation temperature (Tc)
Highest temperature of all outdoor units' high pressure saturated temperature
Load level varies from a minimum of 0 to a maximum of 30 on 1 to 1 basis up to 31 levels.
When the indoor unit stops (including thermostat OFF), the level shows "0".
In the case of test run mode, the actual level implies "30" even if a PC monitor indicates "31".
* In the case that the compressor is stopped from such as special controls, load level does not turn to "0"
even if the indoor unit is most likely to be in stopped state.
The indoor unit demand level varies according to the following 2 conditions.
Intake temperature difference:
Difference between indoor unit remote control set temperature and intake temperature (TA)
Discharge temperature difference:
Difference between preset discharge setting temperature according to the type of indoor unit and
actual discharge temperature (TF)
Load level increases when the differential temperature noted above indicates plus (+) value and
decreases when it indicates minus (-) value.
However, the types of units which are set to control the discharge temperature vary according to the
lowest value from the intake temperature difference and discharge temperature difference.
Horsepower is controlled by the maximum value of all indoor units load level.
Control Functions - Outdoor unit
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2WAY VRF SYSTEM
2WAY SYSTEM
Control Functions
1
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