Mitsubishi Electric PUHY-P200 Service Handbook page 131

Phenomena
1 Cooling with normal remote
controller display but not
providing capacity.
2 Heating with normal remote
controller display but not
providing capacity.
Factors
(7) Clogging by foreign matter
(8) Indoor unit inlet temperature
excessively low
(Less than 15˚C wet bulb)
(9) Faulty compressing
Leaking inside compressor lowers
refrigerant circulation volume.
(10) Faulty action of LEV1
As sufficient sub-cooling can not
be kept at outdoor unit outlet due
to faulty LEV1 action, refrigerant is
difficult to flow at indoor unit.
(11) Faulty TH5, TH7, HPS sensor,
erroneous wiring.
No normal control of LEV1
(1) Insufficient frequency rise
1 Faulty detection of pressure
sensor
2 Higher discharge temperature
exceeding frequency limit
3 Higher high pressure exceeding
frequency limit
(2) Faulty action of indoor unit LEV
Faulty action of indoor unit LEV
does not allow sufficient flow rate.
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Checke method & Handling
Check temperature difference between
before and after a portion (strainer,
distributor) of low pressure piping
where foreign matter may likely be
clogged. Significant temperature drop
may indicate clogging.
→ Remove foreign matter inside piping.
Check inlet temperature and short
cycle at indoor unit side.
To improve using manner
As leaking if existed increases
discharge temperature, judge by
measuring the temperature.
Refer to page of LEV troubleshooting
( 9.[4].5 )
High possibility at little or no difference
between TH5 and TH7
a) Check thermistor.
b) Check wiring.
a) Observe difference between sensor
detected pressure and actual
pressure by monitoring with LED.
→ At abnormal intake, check the
pressure sensor. (Refer to
Troubleshooting of Pressure
Sensor
Note: Higher intake of high pressure
sensor than actual pressure
causes insufficient capacity.
SW1 setting
High pressure sensor
1 2 3 4 5 6 7 8 9 10
ON
Low pressure sensor
1 2 3 4 5 6 7 8 9 10
ON
(b) Observe difference between
condensing temperature (Tc) and
target condensing temperature
(Tcm) by monitoring with LED.
Note: Higher Te than Tem causes
insufficient capacity.
SW1 setting
Condensing temperature Tc
1 2 3 4 5 6 7 8 9 10
ON
Target condensing temperature Tcm
1 2 3 4 5 6 7 8 9 10
ON
Note: When frequency does not rise
even at lower Tc than Tcm,
frequency restriction by discharge
temperature or high pressure
may be affected.
At high discharge temperature
→ Refer to 1102
At high pressure
→ Refer to 1302
Refer to the page of LEV troubleshooting.