40MAHB: Service Manual
Manufacturer reserves the right to change, at any time, specifications and designs without notice and without obligations.
9
Main Protection
Fan speed is out of control
When the indoor fan speed is too low (300RPM) or too high (1500RPM)
for a certain time, the unit stops and the LED displays a failure.
Inverter module protection
The inverter module has a protection function for current, voltage and
temperature. If any of these protections engage, the corresponding code
displays on the indoor unit and the unit stops working.
Indoor fan delayed open function
When the unit starts up, the louver activates immediately and the indoor
fan opens 10s later. If the unit is running in the
HEATING
mode, the
indoor fan is 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
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
If only one temperature sensor malfunctions, the air conditioner continues
to work however the error code appears on the LED, in the event of any
emergency use. If more than one temperature sensor malfunctions, 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
appears.
3. Indoor fan can be set to high/med/low/auto
4. The louver operates the same as in the
COOLING
mode.
Fig. 10 —AUTO FAN Mode
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. 11.
Fig. 11 — Indoor Fan Running Rules
The
AUTO
fan is controlled by the rules shown in Fig. 12.
Fig. 12 — Indoor Fan Running Rules
Evaporator Temperature Protection
When the evaporator temperature is less than the setting value, the
compressor stops.
a
b
c
d
e
T1
°C
10.8
°
F (6.0
°
C)
9
°
F (5.0
°
C)
7.2
°
F (4.0
°
C)
4.5
°
F (2.5
°
C)
1.8
°
F (1.0
°
C)
H
(H-L)*0.75+L
(H-L)*0.5+L
(H-L)*0.25+L
L
Setting fan
speed
Actual fan speed
T1-Td
(°F)
L
H
M
