Midea Mini C Series Service Manual page 24

5 Normal Operation Control
5.1 Component Control during Normal Operation
Table 3-5.1: Component control during normal cooling operation
Component
Inverter compressor
DC fan motor
Electronic expansion valve
Four-way valve
Table 3-5.2: Component control during heating operation
Component
Inverter compressor
DC fan motor
Electronic expansion valve
Four-way valve
5.2 Compressor Output Control
The compressor rotation speed is controlled according to the load requirement. Before compressor startup, the outdoor
unit first estimates the indoor unit load requirement according to the nominal capacity of indoor units currently running,
and then correct for ambient temperature. The compressors then start up according to the corrected load requirement.
During operation the compressors are controlled according to the nominal capacity of indoor units currently running and
the indoor unit heat exchanger temperatures.
5.3 Compressor Step Control
The running speed of the compressors in rotations per second (rps) is one third of the frequency (in Hz) of the electrical
input to the compressor motors. The compressor speed can be altered in increments of 1 rps.
5.4 Electronic Expansion Valve Control
The position of electronic expansion valves EXV is controlled in steps from 0 (fully closed) to 480 (fully open).
In cooling mode:
 When the outdoor unit is in standby:
 EXV is at position 304 (steps).
 When the outdoor unit is running:
 EXV is controlled according to discharge temperature.
In heating mode:
 When the outdoor unit is in standby:
 EXV is at position 304 (steps).
 When the outdoor unit is running:
 EXV is controlled according to discharge temperature.
Wiring diagram
8~16kW
label
COMP
●
FAN ●
EEV ●
ST1 ●
Wiring diagram
8~16kW
label
COMP
●
FAN ●
EEV ●
ST1 ●
Mini C Series VRF 50/60Hz
Control functions and states
Controlled according to load requirement
Fan speed controlled according to heat exchanger temperature
(T3), outdoor ambient temperature (T4),discharge temperature
(T5)and compressor frequency.
Controlled according to discharge temperature
Off
Control functions and states
Controlled according to load requirement
Fan speed controlled according to outdoor unit heat exchanger
refrigerant temperature (T3),outdoor ambient temperature (T4) and
compressor frequency.
Controlled according to discharge temperature
On
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