Mitsubishi Electronics PKA-A24KA4.TH, PKA-A36KA4.TH, PKA-A30KA4.TH SELF-DIAGNOSIS Action Table

Page 16

9-3. SELF-DIAGNOSIS ACTION TABLE

Note: Refer to the manual of outdoor unit for the details of display such as F, U, and other E.

Error Code

Abnormal point and detection method

Cause

 

Countermeasure

 

Room temperature thermistor (TH1)

Defective thermistor

– Check resistance value of thermistor.

 

The unit is in 3-minute resume

characteristics

0

• • • • • • • • • • 15.0k

 

prevention mode if short/open of

Contact failure of connector

10

• • • • • • • • • • • • 9.6k

 

thermistor is detected. Abnormal if the

(CN20) on the indoor controller

20

• • • • • • • • • • • • 6.3k

 

unit does not reset normally after 3 min-

board (Insert failure)

30

• • • • • • • • • • • • 4.3k

 

utes. (The unit returns to normal opera-

Breaking of wire or contact

40

• • • • • • • • • • •3.0k

 

tion, if it has been reset normally.)

failure of thermistor wiring

If you put force on (draw or bend) the lead wire

 

Constantly detected during cooling,

Defective indoor controller

while measuring resistance value of thermis-

 

drying, and heating operation.

board

tor, breaking of wire or contact failure can be

 

Short: 90

 

detected.

 

 

P1

Open: -40

 

Check contact failure of connector (CN20) on

 

 

the indoor controller board. Refer to 9-7.

 

 

 

Turn the power on again and check restart

 

 

 

after inserting connector again.

 

 

 

Check room temperature display on remote

 

 

 

controller.

 

 

 

 

 

Replace indoor controller board if there is

 

 

 

abnormal difference with actual room

 

 

 

temperature.

 

 

 

 

Turn the power off, and on again to operate

 

 

 

after check.

 

 

 

 

 

 

 

Pipe temperature thermistor/Liquid

Defective thermistor

– Check resistance value of thermistor.

 

(TH2)

characteristics

For characteristics, refer to (P1) above.

 

The unit is in 3-minute resume

Contact failure of connector

Check contact failure of connector (CN44) on

 

prevention mode if short/open of

(CN44) on the indoor controller

the indoor controller board. Refer to 9-7.

 

thermistor is detected. Abnormal if the

board (Insert failure)

Turn the power on and check restart after

 

unit does not reset normally after 3 min-

Breaking of wire or contact

inserting connector again.

 

utes. (The unit returns to normal opera-

failure of thermistor wiring

Check pipe <liquid> temperature with remote

 

tion, if it has been reset normally.)

Defective refrigerant circuit is

controller in test run mode. If pipe <liquid>

P2

Constantly detected during cooling,

causing thermistor tempera-

temperature is extremely low (in cooling

drying, and heating (except defrosting)

ture of 90

mode) or high (in heating mode), refrigerant

 

 

operation.

-40

circuit may have defect.

 

Short: 90

Defective indoor controller

Check pipe <liquid> temperature with remote

 

Open: -40

board

controller in test run mode. If there is extremely

 

 

 

difference with actual pipe <liquid> temperature,

 

 

 

replace indoor controller board.

 

 

 

Turn the power off, and on again to operate

 

 

 

after check.

 

 

 

 

 

 

 

Contact failure of drain float switch (CN4F)

Contact failure of connector

Check contact failure of float switch connec-

 

Extract when the connector of drain float

(Insert failure)

tor.

 

 

P4

switch is disconnected.

 

Turn the power on again and check after

( and of connector CN4F is not

 

inserting connector again.

(5701)

 

short-circuited.)

Defective indoor controller

Operate with connector (CN4F) short-circuited.

 

 

Constantly detected during operation.

board

Replace indoor controller board if abnormality

 

 

 

reappears.

 

 

 

 

 

 

 

Drain overflow protection operation

Malfunction of drain pump

Check if drain pump works.

 

Suspensive abnormality, if drain float

Defective drain

Check drain function.

 

 

switch is detected to be underwater for

Clogged drain pump

 

 

 

 

1 minute and 30 seconds continuously

Clogged drain pipe

 

 

 

 

with drain pump on.

Defective drain float switch

Remove drain float switch connector CN4F

 

Turn off compressor and indoor fan.

Catch of drain float switch or

and check if it is short (Switch On) with the

 

Drain pump is abnormal if the condition

malfunction of moving parts

moving part of float switch UP, or OPEN with

 

above is detected during suspensive

cause drain float switch to be

the moving part of float switch down.

 

abnormality.

detected under water (Switch

Replace float switch if it is short with the

P5

Constantly detected during drain pump

On)

moving part of float switch down.

 

operation.

Defective indoor-controller

Replace indoor controller board if it is short-

 

 

board

circuited between -

of the drain float

 

 

 

switch connector CN4F and abnormality

 

 

 

reappears.

 

 

 

 

 

It is not abnormal if there is no problem about

 

 

 

the above-mentioned

~

 

 

 

Turn the power off, and on again to operate

 

 

 

after check.

 

 

 

 

 

 

 

 

16

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Contents Revised EDITION-A ContentsParts Catalog OCB488 Remote controller Optional parts Reference ManualSafety Precaution Always Observe for SafetyPart Names and Functions When charging directly from cylinderFront grille Display Section Operation SectionOperation Mode display Mode Select buttonTemperature setting display Timer displaySpecifications Service RefNoise Criterion Curves PKA-A24KA4.THPKA-A30KA4.TH PKA-A24KAL PKA-A30KALPKA-A24KA4.TH PKA-A30KA4.TH PKA-A36KA4.TH Outlines and DimensionsUnit inch mm Wiring Diagram Explanation of symbolsRefrigerant System Diagram Heat exchangerTroubleshooting TroubleshootingAccording to 9-4. Troubleshooting by inferior phenomena MALFUNCTION-DIAGNOSIS Method by Remote Controller ProcedureWired remote controller Case of trouble during operationU9,UH Wired remote controller LED 1, 2 PCB in outdoor unit Unit’s power terminal block L1, L2, GRAppear even when operation Remote controller wire shortSELF-DIAGNOSIS Action Table Pipe temperature OperatingCause Countermeasure Pipe temperature thermistor Remote controller transmissionErrorE0/signal receiving errorE4 Condenser-Evaporator TH5Error Signal receiving error Error Transmitting errorRemote controller control board Indoor/outdoor unit communicationTroubleshooting by Inferior Phenomena Phenomena Cause Countermeasure 1Upward/downward vanePerformance failure ControllerWhen the remote controller cannot be used Emergency OperationHeat pump type Cooling Only typeLower temperature Condenser/evaporator temperatureThermistor Thermistor TH5Sensor signal check DC Fan motor fan motor/indoor controller circuit boardTest Point Diagram Functions of DIP Switch and Jumper Wire Special Function OperationRotation function and Back-up function Outline of functions System constraintRequest Code List Rotation setting2nd stage cut-in setting 2nd unit Cut-outHow to connect Setting method of each function by wired remote controllerBACK-UP Heating Function CN152 Outline of functionsDisassembly Procedure Operation Procedure Photos & IllustrationsBe careful when removing heavy parts PhotoRemoving the Nozzle Assembly with Vane Operation Procedure PhotosVane Motor and Drain Hose Disconnect the connector CN44 on the indoor controller Remove the panel and the corner box. Refer to stepRemove the screw fixing motor band. See Photo Remove the liquid pipe thermistor and cond / eva thermistorRemove the room temperature thermistor Disconnect the connector CN20 on the indoor controller Board

PKA-A36KA4.TH, PKA-A30KA4.TH, PKA-A24KA4.TH specifications

Mitsubishi Electronics introduces its PKA series of commercial air conditioners, comprising models PKA-A24KA4.TH, PKA-A30KA4.TH, and PKA-A36KA4.TH. These units are designed to meet the growing demand for energy-efficient and reliable climate control solutions in commercial spaces. Each model in the series is equipped with advanced features that set them apart in the competitive air conditioning market.

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