High Ceiling Control - Mitsubishi Heavy Industries FDT40VF Technical Manual

4) In case of anomaly
a) If any anomaly occurs on a unit in a group (a protective function operates), that unit stops with the anomalous
stop but any other normal units continue to run as they are.
b) Signal wiring procedure
Signal wiring between indoor and outdoor units should be made on each unit same as the normal wiring.
For the group control, lay connect with sires wiring between rooms using terminal blocks (X, Y) of remote
controller.
Connect the remote controller communication wire separately from the power supply wire or wires of other
electric devices (AC220V or higher).

(18) High ceiling control

When sufficient air flow rate cannot be obtained from the indoor unit which is installed at a room with high ceiling, the air flow
rate can be increased by changing the fan tap. To change the fan tap, use the indoor unit function "FAN SPEED SET" on the
wired remote controller.
Fan tap
STANDARD
FAN SPEED SET
HIGH SPEED1, 2
Notes (1) Factory default is Standard.
(2) At the hot-start and heating thermostat OFF, or other, the indoor unit fan is operated at the low speed tap of each setting.
(3) This function is not able to be set with wireless remote controls or simple remote control (RCH-E3)
(19) Abnormal temperature thermistor (return air/indoor heat exchanger) wire/short-circuit detection
(a) Broken wire detection
When the return air temperature thermistor detects -20°C or lower or the heat exchanger temperature thermistor detect
-40°C or lower for 5 seconds continuously, the compressor stops. After a 3-minute delay, the compressor restarts but,
if it is detected again within 60 minutes after the initial detection for 6 minutes continuously, stops again (the return air
temperature thermistor: E7, the heat exchanger temperature thermistor: E6).
(b) Short-circuit detection
If the heat exchanger temperature thermistor detects 70°C or higher for 5 seconds continuously at 2 minutes and 20
seconds after the compressor ON during cooling operation, the compressor stops (E6).
(20) External input/output control (CnT or CnTA)
Be sure to connect the wired remote controller to the indoor unit. Without wired remote controller remote operation by CnT is
not possible to perform.
・ All model
Option
1
2
XR1
CnT 3
XR2
Blue
4
12V XR3
5
XR4
6
XR5
■ Priority order for combinations of CnT and CnTA input.
① Operation stop level
② Operation stop pulse
③ Operation permission/prohibition level CnT ③ > CnTA ①
CnT
④ Operation permission/prohibition pulse CnT ④
⑤ Cooling/heating selection level CnT ⑤ / CnTA ①
⑥ Cooling/heating selection pulse CnT ⑥ / CnTA ①
Note (1) Following operation commands are accepted when the operation prohibition is set with CnTA as indicated with *.
Individual operation command from remote controller, test run command from outdoor unit and operation command from optional device, CNT in put.
Reference: Explanation on the codes and the combinations of codes in the table above
1. In case of CnT "Number", the CnT "Number" is adopted and CnTA is invalidated.
2. In case of CnTA "Number", the CnTA "Number" is adopted and CnT is invalidated.
3. In case of CnT "Number"/CnTA "Number", the CnT "Number" and the CnTA "Number" become independent functions each other.
4. In case of CnT "Number" + CnTA "Number", the CnT "Number" and the CnTA "Number" become competing functions each other.
5. In case of CnT "Number" > CnTA "Number", the function of CnT "Number" supersedes that of CnTA "Number".
6. In case of CnT "Number" < CnTA "Number", the function of CnTA "Number" supersedes that of CnT "Number".
(The "Number" above means ① - ⑦ in the table.)
Indoor unit airflow setting
- - -
PHi - Hi - Me - Lo
PHi - PHi - Hi - Me
① Operation output
② Heating output
③ Thermostat ON output
④ Error output
⑤ Remote operation input
① Operation ② Operation
stop level stop pulse
CnT ① CnT ①
CnT ② CnT ②
CnT ③ > CnTA ②
CnT ④
CnT ⑤ / CnTA ②
CnT ⑥ / CnTA ②
-
- - -
Hi - Me - Lo Hi - Lo
PHi - Hi - Me PHi - Me
(CnT-2: XR1)
(CnT-3: XR2)
(CnT-4: XR3)
(CnT-5: XR4)
(CnT-6: Volt-free contact)
CnTA
③ Operation ④ Operation
permission/prohibition permission/prohibition pulse
CnT ① + CnTA ② CnT ①
CnT ② + CnTA ③ CnT ②
CnT ③ + CnTA ③ CnT ③
CnT ④ + CnTA ③※ CnT ④
CnT ⑤ / CnTA ③ CnT ⑤ / CnTA ④
CnT ⑥ / CnTA ③ CnT ⑥ / CnTA ④
304
-
'12 • PAC-T-173
-
Hi - Me
PHi - Hi
・ FDT, FDUM only
CnTA
Blue
12V
XR6
Note (1) CnTA function can be
changed by RC-EX1A.
⑤ Cooling/heating ⑥ Cooling/heating
selection level selection pulse
CnT ① / CnTA ⑤ CnT ① / CnTA ⑥
CnT ② / CnTA ⑤ CnT ② / CnTA ⑥
CnT ③ / CnTA ⑤ CnT ③ / CnTA ⑥
CnT ④ / CnTA ⑤ CnT ④ / CnTA ⑥
CnT ⑤ CnT ⑤
CnT ⑥ CnT ⑥
⑦ Emergency
stop
CnT ① < CnTA ⑦
CnT ② < CnTA ⑦
CnT ③ < CnTA ⑦
CnT ④ < CnTA ⑦
CnT ⑤ / CnTA ⑦
CnT ⑥ / CnTA ⑦