Mitsubishi Heavy Industries FDT71VNXVD Service Manual page 11

(s) Abnormal temperature thermistor (return air/indoor heat exchanger) wire/short-circuit detection
1) Broken wire detection
When the return air temperature thermistor detects -50°C or lower or the heat exchanger temperature thermistor detect
-50°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).
2) 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).
(t) Operation permission/prohibition
(In case of adopting card key switches or commercially available timers)
When the indoor function setting of wired remote controller for "Operation permission/prohibition" is changed from "Invalid
(Factory default)" to " Valid", following control becomes effective.
1
2
CnT 3
Blue
4
12V
5
6
CnT-6
*1 Only the "LEVEL INPUT" is acceptable for external input, however when the indoor function setting of
"Level input (Factory default)" or "Pulse input" is selected by the function for "External input" of the wired remote
controller, operation status will be changed as follows.
In case of "Level input" setting
Unit operation from the wired
remote controller becomes
available*(1)
*(1) In case that "Operation permission/prohibition mode" setting is "Valid" and "External input" setting is "Level
input (Factory default)";
① When card key switch is ON (CnT-6 ON: Operation permission), start/stop operation of the unit from the
wired remote controller becomes available.
② When card key switch is OFF (CnT-6 OFF: Operation prohibition), the unit stops operation in conjunction
with OFF signal, and start/stop operation of the unit from the wired remote controller becomes not available.
*(2) In case that "Operation permission/prohibition mode" setting is "Valid" and "External input" setting is "Pulse
input (Local setting)";
①
When card key switch is ON (Operation permission), the unit starts operation in conjunction with ON signal.
and also start/stop operation of the unit from the wired remote controller becomes available.
② When card key switch is OFF (Operation prohibition), the unit stops operation in conjunction with OFF signal, and
start/stop operation of the unit from the wired remote controller becomes not available.
(3) This function is invalid only at "Center mode" setting done by central controller.
Optional
XR1
XR2
XR3
XR5
XR4
XR5
Normal operation
(Factory default)
ON
Operation
In case of "Pulse input" setting
Unit starts operation
-
Card key
switch
Operation permission/prohibition mode
"Valid" (Local setting)
OFF ON
Operation
Stop
permission*1
*(2)
11 -
'10 • PAC-SM-137A
OFF
Operation prohibition
(Unit stops)