Basic Functions; Abbreviation S; Fan Mode; Cooling Mode - Century COMFORT-AIRE VMH-SG Series Service Manual

Service Manual - VMHxxSG

3. Basic Functions

3.1 Abbreviation
Unit element abbreviations
Abbreviation Element
T1 Indoor room temperature
T2 Coil temperature of evaporator
T3 Coil temperature of condenser
T4 Outdoor ambient temperature
Tsc Adjusted setting temperature
TP Compressor discharge temperature
3.2

Fan Mode

When fan mode is activated:
• The outdoor fan and compressor cease operation.
• Temperature control is disabled and indoor room
temperature is displayed.
• The indoor fan speed can be set to 1%~100%, or
auto.
• The louver operations are identical to those in cooling
mode.
• Auto fan: In fan-only mode, AC operates the same as
auto fan in cooling mode with the temperature set at
24°C.(Tsc =24°C)
3.3

Cooling Mode

3.3.1 Compressor Control
Reach the configured temperature:
1) When the compressor runs continuously for within 120
minutes.
• If the following conditions are satisfied, the
compressor ceases operation.
• Calculated frequency(fb) is less than minimum limit
frequency(FminC).
• Compressor runs at FminC more than 10 minutes
• T1 is lower than or equal to (Tsc-CDIFTEMP-0.5°C)
Note: CDIFTEMP is EEPROM setting parameter. It is 2°C
usually.
2) When the compressor runs continuously for more than
120 minutes.
• If the following conditions are satisfied, the
compressor ceases operation.
• Calculated frequency(fb) is less than minimum limit
• Compressor runs at FminC more than 10 minutes.
• T1 is lower than or equal to (Tsc-CDIFTEMP).
Note: CDIFTEMP is EEPROM setting parameter. It is 2°C
usually.
3) If one of the following conditions is satisfied, not judge
protective time.
• Compressor running frequency(fr) is more than test
• Compressor running frequency is equal to test
• Change setting temperature.
• Turbo or sleep function on/off
• Various frequency limit shutdown occurs.
3.3.2
1) In cooling mode, the indoor fan operates continuously.
The fan speed can be set to 1%-100%, or auto.
2) Auto fan
For DC fan motor units:
• Descent curve
• When T1-Tsc is lower than or equal to 3.5°C, fan
• When T1-Tsc is lower than or equal to 1°C, fan
• When T1-Tsc is lower than or equal to 0.5°C, fan
• When T1-Tsc is lower than or equal to 0°C, fan
• When T1-Tsc is lower than or equal to -0.5°C, fan
• Rise curve
• When T1-Tsc is higher than 0°C, fan speed
• When T1-Tsc is higher than 0.5°C, fan speed
• When T1-Tsc is higher than 1°C, fan speed
• When T1-Tsc is higher than 1.5°C, fan speed
• When T1-Tsc is higher than 4°C, fan speed
 Product Features
Product Features 4
frequency(FminC).
frequency(TestFre).
frequency, T4 is more than 15°C or T4 fault.
Indoor Fan Control
speed reduces to 80%;
speed reduces to 60%;
speed reduces to 40%;
speed reduces to 20%;
speed reduces to 1%.
increases to 20%;
increases to 40%;
increases to 60%;
increases to 80%;
increases to 100%.
4 