Mitsubishi Electric City Multi PQHY-P72 Service Handbook page 207

[ IX Troubleshooting ]
Temperature sensor failure (heat source unit)
Error Code
5101 Discharge
(TH11)
5105 Piping
(TH5)
5106 Inlet water
temperature
(TH6)
5107 Liquid
temperature
(TH7)
5108 SC coil bypass
outlet
(TH8)
5109 Outlet water
temperature
(TH9)
5112 Inverter cool-
ing heat ex-
changer
(THINV)
Error definition and error
detection method
1. When a short (high (1) Thermistor failure
temperature intake) or
an open (low tempera-
(2) Pinched lead wire
ture intake) of the ther-
mistor is detected (the
first detection), the
(3) Torn wire coating
heat source unit stops,
turns to anti-restart
mode for 3 minutes,
(4) A pin on the male connec-
and restarts when the
detected temperature
of the thermistor.
2. When a short or an
(5) Disconnected wire
open is detected again
(the second detection)
after the first restart of
(6) Thermistor input circuit
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",
"5105" , "5106" ,
"5107" , "5108" ,
"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.
- 198 -
Cause
Check thermistor resistance.
Check for pinched lead wire.
Check for wire coating.
Check connector.
tor is missing or contact
failure
Check for wire.
Check the intake temperature of the
failure on the main board sensor with the LED monitor.
When the temperature is far different
from the actual temperature, replace
the control board.
Short detection
TH11 240 C [464 F ] and above (0.57 k )
110 C [230 F ] and above (0.4 k )
TH5
TH6 110 C [230 F ] and above (0.4 k )
TH7 70 C [158 F ] and above (1.14 k )
70 C [158 F ] and above (0.4 k )
TH8
TH9 110 C [230 F ] and above (0.4 k )
THINV 110 C [230 F ] and above (0.4 k )
Check method and remedy
Open detection
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 )
-40 C [ -40 F ] and below (130 k )
-40 C [ -40 F ] and below (130 k )
-40 C [ -40 F ] and below (130 k )