Mitsubishi Electric MSC-07RV Service Manual page 127

d d 2 2 <Only MXZ-32RV>
Low pressure switch protec-
(d2)
tion
d d 1 1
Low discharge temperature
protection
(d1)
p p 4 4
<Only MXZ-32RV>
Compressor stop by thermo-
(P4)
stat function
Symptom
Display Detecting method
d d 8 8
Frequency drop by current
protection
(d8)
d d 9 9
Frequency drop by overload
protection
(d9)
Frequency drop by high pres-
d d 7 7
sure protection
(d7)
Frequency drop by defrosting
in cooling
d d 6 6
Frequency drop by discharge
temperature protection
(d6)
d d 3 3
Frequency drop by high pres-
sure switch protection
(d3)
d d 2 2
<Only MXZ-32RV>
Frequency drop by low pres-
(d2)
sure switch protection
Symptom
Display Detecting method
e e 7 7
Defrost thermistor abnormality
(E7)
f f 5 5
Room-A pipe temperature
thermistor abnormality
(F5)
f f 6 6
Room-B pipe temperature
thermistor abnormality
(F6)
f f 7 7 <Only MXZ-32RV>
Room-C pipe temperature
(F7)
thermistor abnormality
p p 9 9 <Only MXZ-32RV>
Room-D pipe temperature
(P9)
thermistor abnormality
h h 4 4
Power factor detection abnor-
mality
(h4)
p p 2 2
Shell temperature overheat
protection
(P2)
h h 6 6
Dry protection
(h6)
When the low pressure has been 0.05Mpa(0.5 kgf/cm
or more, the compressor stops and restarts in 3 minutes.
When the discharge temperature has been 35˚C or below for 50 min-
utes or more, the compressor stops and restarts operation in 3 minutes.
When the compressor inner thermostat detects 130˚C or above, the
compressor stops and restarts operation in 3 minutes.
Outdoor unit operates. (The compressor operates at reduced frequency.)
Detecting method
When the outdoor unit input current exceeds 16A(MXZ-18RV) 22.5 A
(MXZ-32RV), the compressor operates at reduced frequency.
When the compressor load exceeds the specified value, the compres-
sor operates at reduced frequency.
When indoor pipe temperature exceeds 55˚C during heating, the com-
pressor operates at reduced frequency.
When the indoor pipe temperature falls to 6˚C or below during cooling,
the compressor operates at reduced frequency.
When the discharge temperature exceeds 115˚C, the compressor oper-
ates at reduced frequency.
When the high pressure exceeds 2.75MPa (28 kgf/cm
pressor operates at reduced frequency. In addition, the two-way valve
reverses and the fan speed changes.
When the low pressure falls to 0.05Mpa or below, the compressor oper-
ates at reduced frequency. In addition, the two-way valve opens.
Outdoor unit operates.
Detecting method
When a short or open circuit occurs in the defrost thermistor during
heating
* In this case, the compressor continues to operate.
When a shot or open circuit occurs in the Room-A pipe temperature
thermistor
* In this case, the compressor keeps running.
When a short or open circuit occurs in the Room-B pipe temperature
thermistor
* In this case, the compressor keeps running.
When a short or open circuit occurs in the Room-C pipe temperature
thermistor
* In this case, the compressor keeps running.
When a short or open circuit occurs in the Room-D pipe temperature
thermistor
* In this case, the compressor keeps running.
When the compressor power factor cannot be detected
* In this case, the compressor keeps running.
When the discharge temperature rises to 95˚C or above in single-unit
cooling operation, the outdoor fan speed changes.
When five degrees or more of temperature difference have been detect-
ed between the indoor main temperature and the auxiliary pipe tem-
perature for 10 minutes, the target discharge temperature is reduced.
127
• Check the ball valve.
2
-G) for 5 minutes • Check the pipes for bending or clogging
• Check the LEV operation.
• Replace the outdoor controller board.
• Check the amount of gas.
• Replace the outdoor controller board.
• Check the contact of LEV board connec-
tors.
• Check the inverter output. Refer to G to
K.
• Check the compressor.
• Check the amount of gas.
• Check the indoor unit air filter for clogging.
• Check the indoor/outdoor air flow for short
cycle.
These symptoms do not mean any abno
mality of the product, but check the folling-
points.
• Air filter clogging
• Amount of gas
• Short cycle of indoor/outdoor air flow
2
-G), the com-
• Amount of gas
• Outdoor unit air passage
• Ball valve
• LEV operation
• Pipe bending or clogging
• Outdoor control P.C. board
• Defrost thermistor characteristic
• Contact of P. C. board connectors
• Room A pipe temperature thermistor
characteristic
• Contact of P.C. board connectors
• Room B pipe temperature thermistor
characteristic
• Contact of P.C. board connectors
• Room C pipe temperature thermistor
characteristic
• Contact of P.C. board connectors
• Room D pipe temperature thermistor
characteristic
• Contact of P.C. board connectors
• Compressor wiring
• Outdoor unit air passage
• Pipe length
This symptom does not mean any abnor-
mality in the product, but check the follow-
ings.
• Amount of gas
• Pipe length
Check points
Check points