Mitsubishi Heavy Industries V Multi FDC71VNX Technical Manual page 110

(19) Abnormal temperature sensor (return air/indoor heat exchanger) broken wire/short-circuit detection
(a) Broken wire detection
When the return air temperature sensor detects -55°C or lower or the heat exchanger temperature sensor detect -55°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 sensor: E7, the heat exchanger temperature sensor: E6).
(b) Short-circuit detection
If the heat exchanger temperature sensor detects short-circuit 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)
External input/output connectors are provided on the indoor unit control PCB, and each input/output is possible to be
changed by RC-EX3A.
Be sure to connect the wired remote control to the indoor unit. Remote operation with CnT/CnTA only is not possible.
 ・ CnT
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 ③ > CnTA ② CnT ③ + CnTA ③ CnT ③
CnT
④ Operation permission/prohibition pulse CnT ④
⑤ Cooling/heating selection level CnT ⑤ / CnTA ① CnT ⑤ / CnTA ② CnT ⑤ / CnTA ③ CnT ⑤ / CnTA ④ CnT ⑤
⑥ Cooling/heating selection pulse CnT ⑥ / CnTA ① CnT ⑥ / CnTA ② CnT ⑥ / CnTA ③ CnT ⑥ / CnTA ④ CnT ⑥
Note (1) Following operation commands are accepted when the operation prohibition is set with CnTA as indicated with *.
Individual operation command from remote control, test run command from outdoor unit and operation command from option device, CnT input.
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 - ⑥ in the table.)
(a) Output for external control (remote display)
Indoor unit outputs the following signal for operation status monitoring.
Output name
1 Operation output
2 Heating output
3 Compressor ON output
4 Inspection(Error) output
5 Cooling output
6 Fan operation output 1
7 Fan operation output 2
8 Fan operation output 3
9 Defrost/oil return output
10 Ventilation output
11 Free cooling output
12 Indoor unit overload alrm output Refer to "IU overload alarm"
13 Heater output
・ CnTA
1
CnTA
Blue

2
12V
XR6
(Volt-free contact)"
① Operation stop ② Operation stop
level pulse
CnT ① CnT ①
CnT ② CnT ②
CnT ④
During operation
During heating operation
During compressor operation
When anomalous condition occurs.
During cooling operation
When indoor unit's fan is operating
When indoor unit's fan is operating, and fan speed is higher than Hi speed.
When indoor unit's fan is operating, and fan speed is Lower than Me speed.
When indoor unit receive defrost/oil return signal from the outdoor unit.
When "Venti.ON" is selected from remote control
When the ambient temperature is between 10 - 18°C in cooling and fan operation
Refer to "(8) Thermostat operation (b) Heating"
-
Input/Output Connector
CnT-2 (XR1)
CnT-3 (XR2)
Output
CnT-4 (XR3)
CnT-5 (XR4)
"Input CnT-6 (XR5)
CnTA (XR6)
CnTA
③ Operation ④ Operation
permission/prohibition permission/prohibition pulse
CnT ① + CnTA ② CnT ①
CnT ② + CnTA ③ CnT ②
CnT ④ + CnTA ③※ CnT ④
109
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'19 • PAC-T-327
Factory default setting RC-EX3A function name
Operation output External output 1
Heating output External output 2
Compressor ON output External output 3
Inspection(Error) output External output 4
Remote operation input External input 1
Remote operation input External input 2
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 ⑥
Condition