12-3. Troubleshooting check table

Note . LED indicates "00" in the normal status.

7-segment LED display

Error mode

00

Normal

❈If there is defect in the following parts(electronic control P.C. board, relay P.C. board, high pressure switches(63H1,63H2),indoor /outdoor fan motor , or indoor coil thermistor), the compressor may stop even with the display remained at “ 00 “.In any case, reset the breaker and check the above-stated parts.

Symptom

 

Outdoor unit does not operate.

 

 

 

 

 

Display

Detecting method

Detecting method

Check points

 

 

 

 

a4

Outdoor power system abnor-

When the compressor operation has been interrupted by overcurrent

• Inverter output

(A4)

mality

protection continuously three times within 1 minute after start-up, the

• Compressor

 

compressor stops operation.

 

 

 

 

 

a3

Outdoor electronic control P.C.

When the nonvolatile memory data cannot be read properly on the out-

• Outdoor electronic control P.C. board

(A3)

board abnormality

door controller board

 

 

 

 

 

p1

Indoor unit and LEV abnor-

When the drain abnormality is detected in the indoor unit and the indoor

• Check the abnormality indication on the

main coil temperature is too low, or when any abnormality is detected in

indoor unit.

(P1)

mality

the components of indoor unit

• LEV

 

 

 

 

 

 

 

 

 

Symptom

 

Outdoor unit stops and restarts every 3 minutes.

 

 

 

 

 

Display

Detecting method

Detecting method

Check points

 

 

 

 

 

 

 

• Check the characteristic of the evapora-

e9

Evaporation temperature ther-

The compressor stops when a short or open circuit occurs in the evap-

tion temperature thermistor. Refer to F

(E9)

mistor abnormality

oration temperature thermistor during compressor running.

on page 31.

• Check the contact of P. C. board con-

 

 

 

 

 

nectors.

 

 

 

 

 

 

 

• Check the characteristic of the discharge

e6

Discharge temperature ther-

The compressor stops when a short or open circuit occurs in the dis-

temperature thermistor. Refer to F on

(E6)

mistor abnormality

charge temperature thermistor during compressor running.

page 31.

• Check the contact of P. C. board con-

 

 

 

 

 

nectors.

 

 

 

 

f8

 

 

• Check the characteristic of the fin temper-

Fin temperature thermistor

The compressor stops when a short or open circuit occurs in the fin tem-

ature thermistor. Refer to F on page 31.

(F8)

abnormality

perature thermistor during compressor running.

• Check the contact of P.C. board connec-

 

 

tors.

 

 

 

 

 

 

 

 

 

 

• Check the inverter and compressor.

 

 

 

Refer to E on page 30.

a8

Overcurrent protection

When over current is applied to the power module, the compressor

• Check the amount of gas.

(A8)

stops and restarts in 3 minutes.

• Check the indoor/outdoor air flow for

 

short cycle.

 

 

 

 

 

• Check the indoor unit air filter for

 

 

 

clogging.

 

 

 

 

d6

Discharge temperature over-

When the discharge temperature thermistor detects 116˚C or above, the

• Check the amount of gas and the refriger-

compressor stops and restarts operation in 3 minutes.

ant cycle.

(d6)

heat protection

(Protection will be released at 100; or below.)

• Check the outdoor unit air passage.

 

 

 

 

 

d4

 

 

• Check the outdoor unit air passage.

Fin temperature overheat pro-

When the fin temperature thermistor detects 89˚C or above, the com-

• Check the power module.

(d4)

tection

pressor stops and restarts operation in 3 minutes.

• Check the outdoor fan motor. Refer to G

 

 

on page 31.

 

 

 

 

 

 

 

d7

High pressure protection

When the compressor starts, primary current or output voltage stops the

• Amount of gas

(d7)

compressor and restarts in 3 minutes.

• Outdoor unit air passage.

 

• Check the ball valve.

 

 

 

 

 

 

f5

Room-A gas pipe temperature

When a short or open circuit occurs in the Room-A gas pipe

• Room A gas pipe temperature thermistor

characteristic.

(F5)

thermistor abnormality

temperature thermistor.

• Contact of P.C. board connectors.

 

 

 

 

 

 

f6

Room-B gas pipe temperature

When a short or open circuit occurs in the Room-B gas pipe

• Room B gas pipe temperature thermistor

characteristic.

(F6)

thermistor abnormality

temperature thermistor.

• Contact of P.C. board connectors.

 

 

 

 

 

 

f7

Room-C gas pipe temperature

When a short or open circuit occurs in the Room-C gas pipe

• Room C gas pipe temperature thermistor

characteristic.

(F7)

thermistor abnormality

temperature thermistor.

• Contact of P.C. board connectors.

 

 

 

 

 

 

25

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Mitsubishi Electronics MXZ-24UV - E2 service manual Troubleshooting check table, Lev
Page 24 Page 26

MXZ-24UV - E2, MXZ-24UV specifications

Mitsubishi Electronics has established itself as a leader in the HVAC (heating, ventilation, and air conditioning) industry with its MXZ-24UV and MXZ-24UV - E2 models. These multi-zone heat pump systems are designed to provide exceptional efficiency, comfort, and versatility for residential and commercial applications.

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