Fan Mode; Cooling Mode; Heating Mode - Carrier 42QHP09E8S Service Manual

1.4

Fan Mode

When fan mode is activated:
• The outdoor fan and compressor are stopped.
• 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)
1.5

Cooling Mode

1.5.1 Compressor Control
Reach the configured temperature:
1) When the compressor runs continuously for less than
120 minutes.
• If the following conditions are satisfied, the
compressor ceases operation.
• While calculated frequency(fb) is less than minimum
limit frequency(FminC).
• While protective time is more than or equal to ten
minutes.
• While 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.
• When calculated frequency(fb) is less than minimum
limit frequency(FminC).
• When protective time is more than or equal to ten
minutes.
• When 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 is more than test
frequency.
• When compressor running frequency is equal to
test frequency, T4 is more than 15°C or no T4 or T4
 Page 14 
fault.
• Change setting temperature.
• Turbo or sleep function on/off
• Various frequency limit shutdown occurs.
Note: CDIFTEMP is EEPROM setting parameter. It is 2°C
usually.
1.5.2 Indoor Fan Control
1) In cooling mode, the indoor fan operates continuously.
The fan speed can be set to 1%-100%, or auto.
2) Auto fan
• Descent curve
• When T1-Tsc is lower than or equal to 3.5°C, fan
speed reduces to 80%;
• -When T1-Tsc is lower than or equal to 1°C, fan
speed reduces to 60%;
• -When T1-Tsc is lower than or equal to 0.5°C, fan
speed reduces to 40%;
• -When T1-Tsc is lower than or equal to 0°C, fan
speed reduces to 20%;
• -When T1-Tsc is lower than or equal to -0.5°C, fan
speed reduces to 1%.
• Rise curve
• When T1-Tsc is higher than 0°C, fan speed
increases to 20%;
• -When T1-Tsc is higher than 0.5°C, fan speed
increases to 40%;
• -When T1-Tsc is higher than 1°C, fan speed
increases to 60%;
• -When T1-Tsc is higher than 1.5°C, fan speed
increases to 80%;
• -When T1-Tsc is higher than 4°C, fan speed
increases to 100%.
1.5.3 Outdoor Fan Control
• The outdoor unit will be run at different fan speed
according to T4 and compressor running frequency..
• For different outdoor units, the fan speeds are
different.
1.5.4 Condenser Temperature Protection
When the condenser temperature exceeds a configured
value, the compressor ceases operations.
1.5.5 Evaporator Temperature Protection
When evaporator temperature drops below a configured
value, the compressor and outdoor fan ceases operations.
1.6

Heating Mode