Condensate Pump Motor (Dm) Control; Air Flow Mode Control; Compressor Inching Prevention Control; Frost Prevention During Cooling, Dehumidification - Mitsubishi Heavy Industries FDCA Series Technical Manual

(k) Condensate pump motor (DM) Control [FDT and FDUR models only]
(a) Drain motor is started no sooner than the compressor is turned ON during cooling or dehumidifying operation. The drain
motor continues to operate for 5 minutes after the stop of unit operation, stop with the error stop, thermostat stop and at
switching from cooling or dehumidifying operation to blowing or heating operation. When there is any unit subjected to oil
return control, the drain motor is operated for 5 minutes at such occasion.
(b) Overflow detection is performed by the float switch at all times regardless of the operating mode. If the float switch
circuit is detected to be open continuously for 3 seconds (or when the float switch is disconnected or a wire is broken), an
abnormal stop (E9) is performed and the condensate pump motor runs until the float switch recovers.
(l)

Air flow mode control

Air flow mode control can be changed using DIP switch SW9-4 on the indoor PCB.
FDT, FDEN, FDKN models
SW9-4 OFF
DIP SW
(Mild Mode Control)
Item
Air flow mode
Notes (1) When the unit is shipped, SW9-4 is turned ON.
Notes (2) If SW9-4 is ON, the fan operates in Me even during hot start and
when the heating thermostat is OFF.
(m) Compressor inching prevention control
1) 3-minute timer
If the compressor stops due to operation of the thermostat, the Run switch on the remote controller or some trouble, it is not
restarted after 3 minutes. However, when the power is turned ON, the 3-minute timer becomes inactive.
2) 3-minute forced operation timer
a) For 3 minutes after the compressor goes ON, it does not stop. However, it will stop if the Run/Stop button is pressed
and through a change in the operation mode, it sill stop immediately when the thermostat goes OFF.
b) During 3-minute forced operation timer control in heating operation, if the thermostat goes OFF, the louver position
is set in the horizontal position.
Note (1) The compressor stops when protection control starts.
(n) Heating overload porotection
If a temperature of 63ºC or higher is detected in the indoor heat exchanger continuously for 2 seconds (sensed by Thi-R1 of
R2), the compressor stops. After a 3-minute delay, the compressor is restarted. If a temperature of 63ºC or higher is detected
continuously for 2 seconds 5 times within 60 minutes of the first detection, an abnormal stop is performed (E8). Detection of
a temperature of 63ºC or higher in the indoor heat exchanger continuously for 6 minutes also results in an abnormal stop.
(o) Frost prevention during cooling, dehumidification
If an indoor heat exchanger temperature is 1˚C or lower is deteted (by ThI-R1 or R2) when 9 minutes have passed since the
compressor went ON, the compressor stops. The compressor runs when the indoor heat exchanger temperature becomes
10˚C or higher.
(p) Thermistor (Return air, heat exchanger) disconnected wire detection.
If the temperature sensed by the thermistor is –50ºC or lower continuously for 5 seconds, the compressor stops. After a 3-
minute delay, the compressor is restarted, but if a recurrence is detected within 60 minutes of the 1st time, or if it is sensed
continuously for 6 minutes, it results in an abnormal stop (E6, E7).
SW9-4 ON
(Powerful mode Control)
Hi, Me, Lo UHi, Hi, Me
Compressor operation
56
Indoor heat exchanger temperature(˚C)
Fan operation
1.0
Indoor heat exchanger temperature (˚C)
FDUR model
DIP SW
Item
Air flow mode
Notes (1) When the unit is shipped, SW9-4 is turned OFF.
Notes (2) If SW9-4 is ON, the fan operates in Hi even during hot start and
when the heating thermostat is OFF.
Compressor stop
63
Cooling operation
10
72
- -
SW9-4 OFF SW9-4 ON
(Standard) (High speed)
Hi, Lo UHi, Hi