Mitsubishi Electric CITY MULTI PQRY-P200YMF-C Service Handbook page 107

Checking code Meaning, detecting method
1111 Low 1. When saturation temperature
pressure sensor (TH2) detects -40˚C or
saturation less (the first time) during op-
tempera- erations, heat source unit stops
ture once, mode is changed to re-
sensor start mode after 3 minutes, then
abnormal- the heat source unit restarts.
ity (TH2)
2. When -40˚C or less temp. is
detected again (the second
time) within 30 minutes after
stop of heat source unit, error
stop is observed with code Nos.
"1111" displayed.
3. When -40˚C or less tempera-
ture is detected 30 or more min-
utes after stop of heat source
unit, the stop is regarded as the
first time and the process
shown in 1. is observed.
4. 30 minutes after stop of heat
source unit is intermittent fault
check period with LED dis-
played.
Note:
1. Low press. saturation tem-
perature trouble is not de-
tected for 3 minutes after
compressor start, and finish
of defrosting operations, and
during defrosting operations.
2. In the case of short/open of
TH2 sensors before starting
of compressor or within 10
minutes after starting of com-
pressor, "1111" is displayed
too.
Cause
1) Gas leak, Gas shortage.
2) Insufficient load operations.
3) Poor operations of indoor LEV.
4) Poor operations of BC controller
LEV:
Cooling-only : LEV3
Cooling-main : LEV1, 3
Heating-only, Heating-main:
LEV3
5) Poor operations of BC controller
SVM:
Cooling-only, Defrost
6) Poor operations of BC controller
SVM:
Cooling-only, Cooling-main
7) Poor operations of BC controller
SVB:
Heating-only, Heating-main
8) Solenoid valve trouble (SV3 ~ 6,
SV73).
Heating-only, Heating-main
9) Setting error of connection address.
10)Poor operations of ball valve.
11)Short cycle of indoor unit.
12)Clogging of indoor unit filter.
13)Fall in air volume caused by dust
on indoor unit fan.
14)Dust on indoor unit heat exchanger.
15)Indoor unit block, Motor trouble.
9)~14) : Fall in low pressure
caused by evaporating capac-
ity in cooling-only cooling-prin-
cipal operation.
16)Short cycle of heat source unit.
17)Dust on outdoor heat exchanger.
18)Indoor unit fan block, motor trouble,
and poor operations of fan control-
ler.
15)~17) : Fall in low press. caus-
ed by lowered evaporating
capa-city in heating-only heat-
ing-principal operation.
19)Poor operations of solenoid valve
SV2.
Bypass valve (SV2) can not
control low pressure drop.
20)Thermistor trouble (TH2~TH10).
21)Pressure sensor abnormality.
22)Control circuit board thermistor
abnormality and pressure sensor
input circuit abnormality.
23)Poor mounting of thermistor
(TH2~TH10).
–106–
Checking method & Countermeasure
See Refrigerant amount check.
Check operating conditions and opera-
tion status of heat source unit.
Check operation status by actually per-
forming cooling-only or heating-only
operations.
Cooling-only : indoor LEV
LEV1, 3 (BC)
SVA (BC)
Heating-only : indoor LEV
LEV3 (BC)
SVB (BC)
SV3~6, SV73
See Trouble check of LEV and sole-
noid valve.
Check address setting of indoor unit
connector.
Confirm that ball valve is fully opened.
Check indoor unit, and take measu-res
to troube.
Check heat source unit, and take mea-
sures to trouble.
Check heat source unit fan.
See Trouble check of heat source
unit fan.
See Trouble check of solenoid valve.
Check resistance of thermistor.
See Trouble check of pressure sen-
sor.
Check inlet temp. and press. of sensor
by LED monitor.