Fan Control At Heating Startup; Room Temperature Detection Temperature Compensation During Heating; Return Air Temperature Compensation; High Power Operation - Mitsubishi Heavy Industries FDT Series Technical Manual

(23) Fan control at heating startup

(a) 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.
(b) Contents of control
1) 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
2) If the indoor unit heat exchanger temperature drops below 37°C at next sampling, present number of revolutions of
indoor unit fan speed is reduced by 10min
(c) End conditions
the start of heating operation.

(24) Room temperature detection temperature compensation during heating

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 "
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

(25) 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.
(26) High power operation (RC-EX1A only)
maximum.
(27) Energy-saving operation (RC-EX1A only)
It operates with the setting temperature fixed at 28°C for cooling, 22°C for heating or 25°C for auto. (Maximum capacity is
restricted at 80%.)
(28) Warm-up control (RC-EX1A only)
Operation will be started 5 to 60 minutes before use according to the forecast made by the microcomputer which calculates
when the operation should be started in order to warm up the indoor temperature near the setting temperature at the setting time
of operation start.
(29) Home leave mode (RC-EX1A only)
When the unit is not used for a long period of time, the room temperature is maintained at a moderate leval, avoiding extremely
hot or cool temperature.
(a) Cooling or heating is operated according to the outdoor temperature (factory setting 35°C for cooling, 0°C for heating)
and the set temp. (factory setting 33°C for cooling, 10°C for heating)
(b) Set temp and indoor fan speed can be set by RC-EX1A.
(30) Auto temp. setting (RC-EX1A only)
Setting temperature is adjusted automatically at the adequate temperature the center set temp. is 24°C by correcting the outdoor
air temperature.
Operation
Stop
-1 +1
Room temperature (deg)
• -1.0°C, -1.5°C, -2.0°C
°C for cooling, 30°C for heating and maximum indoor fan speed for 15 minutes
-1 .
". The compressor and the heater are turned ON/OFF
When it is set at +3°C
Compressor
Setting temperature
- 308 -
'12 • PAC-T-173
-1
.
Operation
Stop
+2 +4
Room temperature (deg)
-R) is
I