Service Manual -
B-VMHxxAV-1
Product Features
3
2. Safety Features
Compressor three-minute delay at restart
Compressor functions are delayed for up to ten seconds
upon the first startup of the unit, and are delayed for up
to three minutes upon subsequent unit restarts.
Automatic shutoff based on discharge temperature
If the compressor discharge temperature exceeds a certain
level for nine seconds, the compressor ceases operation.
Inverter module protection
The inverter module has an automatic shutoff mechanism
based on the unit’s current, voltage, and temperature.
If automatic shutoff is initiated, the corresponding error
code is displayed on the indoor unit and the unit ceases
operation.
Indoor fan delayed operation
• When the unit starts, the louver is automatically
activated and the indoor fan will operate after a period
of setting time or the louver is in place.
• If the unit is in heating mode, the indoor fan is
regulated by the anti-cold wind function.
Compressor preheating
Preheating is automatically activated when T4 sensor is
lower than setting temperature.
Sensor redundancy and automatic shutoff
• If one temperature sensor malfunctions, the air
conditioner continues operation and displays the
corresponding error code, allowing for emergency use.
• When more than one temperature sensor is
malfunctioning, the air conditioner ceases operation.
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
TP
Compressor discharge temperature
TS
Setting temperature
Tsc
Adjusted setting temperature
In this manual, such as CDIFTEMP, HDIFTEMP2, TCE1,
TCE2...etc., they are well-setting parameter of EEPROM.
3.2 Fan Mode
When fan mode is activated:
• The outdoor fan and compressor are stopped.
• Temperature control is disabled and no temperature
setting is displayed.
• The indoor fan speed can be set to low, medium, high,
turbo and 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.
3.3 Cooling Mode
3.3.1 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.
• Calculated frequency(fb) is less than minimum limit
frequency(FminC).
• Compressor runs at FminC more than ten minutes.
• T1 is lower than or equal to (Tsc-CDIFTEMP-0.5°C)
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
frequency(FminC).
• Compressor runs at FminC more than 10 minutes.
• When T1 is lower than or equal to (Tsc-CDIFTEMP).
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 T4 fault.
• Change setting temperature.
• High or sleep function on/off
• Various frequency limit shutdown occurs.
3.3.2 Indoor Fan Control
1) In cooling mode, the indoor fan operates continuously.
The fan speed can be set to low, medium, high, turbo
and auto.
Summary of Contents for Comfort-Aire Century A-VMH18SV-1
Page 30: ...Service Manual B VMHxxAV 1 ...
Page 37: ...Service Manual B VMHxxAV 1 Outdoor Unit 3 3 Panel Plate X430 Square grille ...
Page 38: ...Service Manual B VMHxxAV 1 Outdoor Unit 4 4 Panel Plate D30 Square grille ...
Page 39: ...Service Manual B VMHxxAV 1 Outdoor Unit 5 5 2 Service Place Minimim 4 Recommended 12 ...
Page 42: ...Service Manual B VMHxxAV 1 Outdoor Unit 8 8 A VMH18SV 1 A VMH24SV 1 ...
Page 45: ...Service Manual B VMHxxAV 1 ...
Page 103: ...Service Manual B VMHxxAV 1 Troubleshooting 15 ...