Carrier 40MB C Series Service Manual page 12

Main Protection
Fan Speed is Out of Control
When the indoor fan speed remains too low (lower than 300RPM)
for 50s, the indoor fan will shut off and restarts 30 sec later, if
protection occurred 3 times when the fan motor restarts
continuously, the unit stops and the LED displays the failure.
When the outdoor fan speed remains too low (lower than
100RPM) or too high (higher than 1500RPM) for 60 sec, the unit
stops and the LED displays the failure. The malfunction is cleared
30s later.
Inverter Module Protection
The inverter module has a protection function for current, voltage
and the temperature. If any of these protections trigger, the
corresponding code displays on the indoor unit and the unit shuts
down.
Indoor Fan Delayed Open Function
When the unit starts up, the louver becomes active immediately
and the indoor fan opens 10s later. If the unit runs in the
HEATING mode, the indoor fan will be controlled by the
anti−cold wind function.
Zero Crossing Detection Error Protection
If the AC detects that the time interval is not correct for a
continuous period of 240s, the unit stops and the LED displays the
failure. The correct zero crossing signal time interval should be
between 6−13ms.
Sensor Protection at Open Circuit and Breaking Disconnection
When there is only one malfunctioning temperature sensor, the air
conditioner keeps working yet displays the error code, in case of
any emergency use. When there is more than one malfunctioning
temperature sensor, the air conditioner stops working.
Operation Modes and Functions
FAN Mode
1 Outdoor fan and compressor stop
2 Temperature setting function is disabled, and no setting
temperature is displayed.
3 Indoor fan can be set to high/med/low/auto
4 The louver operates the same in the COOLING mode.
T1-75.2°F (24°C)
42.8°F (6°C)
..........................................................................
a
41.0°F (5°C)
b
39.2°F (4°C)
c
36.5°F (2.5°C)
d
33.8°F (1°C)
e
Fig. 11 – Auto Fan
H
(H-L)*0.75+L
........................
(H-L)*0.5+L
........................
(H-L)*0.25+L
........................
L
COOLING Mode
Indoor Fan Running Rules
In the COOLING mode, the indoor fan runs all the time and the
speed can be selected as high, medium, low and auto. When the
setting temperature is reached, if the compressor stops running, the
indoor fan motor runs at the minimum or setting speed.
The indoor fan is controlled by the rules shown in Fig. 12.
Setting Fan
T1-Td °F (°C)
Speed
H
M
L
Fig. 12 – Indoor Fan Running Rules
The AUTO fan is controlled by the rules shown in Fig. 13.
T1-75.2°F (24°C)
42.8°F (6°C)
..........................................................................
a
41.0°F (5°C)
b
39.2°F (4°C)
c
36.5°F (2.5°C)
d
33.8°F (1°C)
e
Fig. 13 – Indoor Fan Running Rules
Evaporator Temperature Protection
When the evaporator temperature is less than the setting value, the
compressor stops.
12
Actual Fan Speed
H
(H-L)*0.75+L
........................
(H-L)*0.5+L
........................
(H-L)*0.25+L
........................
L