Mitsubishi Electric City Multi CMB-P1016NU-G, Service Handbook

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[
IX
Troubleshooting ]
Temperature sensor failure (heat source unit)
Error Code
Error definition and error
detection method
Cause Check method and remedy
5101 Discharge
(TH11) 1. When a short (high
temperature intake) or
an open (low tempera-
ture intake) of the ther-
mistor is detected (the
first detection), the
heat source unit stops,
turns to anti-restart
mode for 3 minutes,
and restarts when the
detected temperature
of the thermistor
2. When a short or an
open is detected again
(the second detection)
after the first restart of
the heat source unit,
the heat source unit
stops, turns to anti-re-
start mode for 3 min-
utes, and restarts in 3
minutes when the de-
tected temperature is
within the normal
range.
3. When a short or an
open is detected again
(the third detection) af-
ter the previous restart
of the heat source
unit, the heat source
unit makes an error
stop.
4. When a short or an
open of the thermistor
is detected just before
the restart of the heat
source unit, the heat
source unit makes an
error stop, and the er-
ror code "5101",
"5106", "5109", or
"5112" will appear.
5. During 3-minute anti-
restart mode, prelimi-
nary errors will be dis-
played on the LED
display.
6. For the first ten min-
utes after compressor
start up, detection of
short or open as listed
above is not per-
formed.
(1) Thermistor failure Check thermistor resistance.
5106 Inlet water
temperature
(TH6) (2) Pinched lead wire Check for pinched lead wire.
5109 Outlet water
temperature
(TH9) (3) Torn wire coating Check wire coating.
5112 Inverter cool-
ing heat ex-
changer
(THINV) (4) A pin on the male connec-
tor is missing or contact
failure
Check connector.
(5) Disconnected wire Check for wire.
(6) Thermistor input circuit
failure on the main board
Check the intake temperature of the
sensor with the LED monitor.
When the temperature is far different
from the actual temperature, replace
the control board.
TH11
TH6
TH9
THINV
Short is detection Open detection
240 C [464 F] and above (0.57 k )
110 C [230 F] and above (0.4k )
110 C [230 F] and above (0.4k )
110 C [230 F] and above (0.4k ) 0 C [32 F] and below (643 k )
-40 C [-40 F] and below (130 k )
-40 C [-40 F] and below (130 k )
-40 C [-40 F] and below (130 k )