Fan Control At Heating Startup; Room Temperature Detection Temperature Compensation During Heating; Return Air Temperature Compensation - Mitsubishi Heavy Industries FDTC50ZHXV Technical Manual

2) Remote operation input
Remote operation inputs (switch input, timer input) connectors (CnT) are provided on the indoor control PCB.
However, the remote operation by the CnT is not effective when "Center mode" is selected with the air-conditioner.
a) Factory default (At the shipping from factory) [Indoor function of wired remote controller "External
input selector" is set at the level input.]
• Startup at the input signal to CnT OFF  ON [Edge input] ... Air-conditioner ON
• Stop at the input signal to CnT ON  OFF [Edge input] ... Air-conditioner OFF
CnT input
Air-conditioner A
Air-conditioner B
b) When the setting is changed to the pulse input at site using the indoor unit function of wired
remote controller "External input selector"
It becomes effective only when the input signal to CnT is changed OFF ➝ ON and the air-conditioner operation [ON/
OFF] is inverted.
CnT input
Air-conditioner A
Air-conditioner B
(v) Fan control at heating startup (Applicable model: FDT)
1) Start conditions
At the start of heating operation, if the difference of setting temperature and return air temperature is 5°C or higher after
the end of hot start control, this control is performed.
2) Contents of control
a) Sampling is made at each minute and, when the indoor unit heat exchanger temperature (detected with Th
37°C or higher, present number of revolutions of indoor unit fan speed is increased by 10min
b) If the indoor unit heat exchanger temperature drops below 35°C at next sampling, present number of revolutions of
indoor unit fan speed is reduced by 10min
3) End conditions
Indoor fan speed is reduced to the setting airflow volume when the compressor OFF is established and at 30 minutes after
the start of heating operation.
(w) Room temperature detection temperature compensation during heating [Applicable model: All models of
the heating and cooling type]
With the standard specification, the compressor is turned ON/OFF with the thermostat setting temperature. When the
thermostat is likely to turn OFF earlier because the unit is installed at the ceiling where warm air tends to accumulate, the
setting can be changed with the wired remote controller indoor unit function "Heating room temperature compensation". The
compressor and the heater are turned ON/OFF at one of the setting temperature +3, +2 or +1°C in order to improve the feeling
of heating. The setting temperature, however, has the upper limit of 30°C.
Standard
Compressor
Setting temperature
(x)

Return air temperature compensation

This is the function to compensate the deviation between the detection temperature by the return air temperature thermistor and
the measured temperature after installing the unit.
1) It is adjustable in the unit of 0.5°C with the wired remote controller indoor unit function "RETURN AIR TEMP".
• +1.0°C, +1.5°C, +2.0°C
2) Compensated temperature is transmitted to the remote controller and the compressor to control them.
Note (1) The detection temperature compensation is effective on the indoor unit thermistor only.
ON
OFF
ON
OFF
*ON ON
ON
OFF OFF
ON
OFF
ON
OFF
Operation
Stop
-1 +1
Room temperature (deg)
• -1.0°C, -1.5°C, -2.0°C
ON
Note (1) ON marked with * means ON by a remote
OFF OFF
*ON
ON
OFF OFF
ON
OFF OFF
ON
OFF
OFF
ON
-1 .
When it is set at +3°C
Compressor
Setting temperature
160
– –
controller switch or other.
-1
.
Operation
+2 +4
Room temperature (deg)
-R) is
I
Stop