Heating Mode(Heat Pump Units) - Mars Comfort-Aire Century VCD-SA Series Service Manual

• Descent curve
• When T1-Tsc is lower than or equal to 3.5°C, fan
speed reduces to high;
• When T1-Tsc is lower than or equal to 1°C, fan
speed reduces to medium;
• When T1-Tsc is lower than or equal to 0.5°C, fan
speed reduces to low;
• Rise curve
• When T1-Tsc is higher than 1°C, fan speed increases
to medium;
• When T1-Tsc is higher than 1.5°C, fan speed
increases to high;
• When T1-Tsc is higher than 4°C, fan speed
increases to turbo.
3.3.3 Outdoor Fan Control
• The outdoor unit will be run at different fan speed
according to T4 and compressor frequency.
• For different outdoor units, the fan speeds are
different.
3.3.4 Condenser Temperature Protection
When the condenser temperature exceeds a configured
value, the compressor ceases operation.
3.3.5 Evaporator Temperature Protection
When evaporator temperature drops below a configured
value, the compressor and outdoor fan cease operation.
3.4

Heating Mode(Heat Pump Units)

3.4.1 Compressor Control
1) Reach the configured temperature
• If the following conditions are satisfied, the
compressor ceases operation.
• Calculated frequency(fb) is less than minimum limit
frequency(FminH).
• Compressor runs at FminH more than 10 minutes.
• T1 is higher than or equal to Tsc+ HDIFTEMP2.
Note: HDIFTEMP2 is EEPROM setting parameter. It is 2°C
usually.
• If one of the following conditions is satisfied, not
judge protective time.
• Compressor running frequency is more than test
frequency.
• Compressor running frequency is equal to test
frequency, T4 is more than 15°C or T4 fault.
• Change setting temperature.
• High or sleep function on/off.
2) When the current is higher than the predefined safe
value, surge protection is activated, causing the
compressor to cease operations.
3.4.2
1) In heating mode, the indoor fan operates continuously.
The fan speed can be set to low, medium, high,turbo
and auto.
• Anti-cold air function
• The indoor fan is controlled by the indoor
temperature T1 and indoor unit coil temperature
T2.
ΔTE1=0
2) Auto fan action in heating mode:
• Rise curve
• When T1-Tsc is higher than -1.5°C, fan speed
reduces to high;
• When T1-Tsc is higher than 0°C, fan speed reduces
to medium;
• When T1-Tsc is higher than 0.5°C, fan speed
reduces to low;
• Descent curve
• When T1-Tsc is lower than or equal to 0°C, fan
speed increases to medium;
• When T1-Tsc is lower than or equal to -1.5°C, fan
speed increases to high;
• When T1-Tsc is lower than or equal to -3°C, fan
speed increases to turbo.
3.4.3
• The outdoor unit will be run at different fan speed
according to T4 and compressor frequency.
• For different outdoor units, the fan speeds are
different.
3.4.4
 Product Features 4
Service Manual - VCDxxSA
Indoor Fan Control:
Outdoor Fan Control:
Defrosting mode
