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Contents

Technical Service Manual

Dishwasher

Specification

2

Test program

24-28

Theory of parts                    5-23

Function Description          3-4

Inspection                            29-32

Location

5

PCB

6-7

Inlet valve

8-10

Drain pump

11-12

Heater

13-14

Washing pump

15-16

Procedure

25

Error code

26-28

Water circuit

3-4

Pressure switch

17

NTC

18-19

Flowmeter                                                   20-21

Safety Hose

22-23

Troubleshooting

33-37

SAFETY NOTICE

This documentation is only intended for qualified technicians
who are aware of the respective safety regulations.

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Summary of Contents for WQP12-7311D

Page 1: ...ocation 5 PCB 6 7 Inlet valve 8 10 Drain pump 11 12 Heater 13 14 Washing pump 15 16 Procedure 25 Error code 26 28 Water circuit 3 4 Pressure switch 17 NTC 18 19 Flowmeter 20 21 Safety Hose 22 23 Troubleshooting 33 37 SAFETY NOTICE This documentation is only intended for qualified technicians who are aware of the respective safety regulations 1 ...

Page 2: ...asic operation instructions please refer to the instruction manual attached with each unit Electrical supply 220 240V 50Hz Supply water pressure 0 04MPa 1 0MPa Supply water temperature below 60 2 Models WQP12 7311D WQP8 7312D ...

Page 3: ...Inlet water route Inlet water route Water circuit scheme Cycle water route Drain water route Water Circuit Function Description 3 ...

Page 4: ...oftener and then enter in the tub During this phase some of inlet water will be stored in the air breaker to be regenerating water Cycle washing action is driven by washing pump motor Water can obtain the power during it passing through the working washing pump then be pumped into spray arm pass from spray arm nozzles over the dishes into sump where connect to washing pump and to get in the next w...

Page 5: ... washing pump sump heater pressure switch softener Please Note Explode view and part list of each model have some different visions So please refer to the newest vision Midea sent you drain pump 5 Location Theory of parts ...

Page 6: ...moved from the protecting box in the bottom of machine 1 Disconnect power supply 2 Take out cutlery basket basket and filter system 3 Open the cover of bottom board 4 Remove the screws for fixing protecting box and open the protecting box cap Access PCB 5 Disconnect the connector form PCB 6 Remove the screws securing the PCB to control panel 7 Remove the PCB 8 Reverse the above procedure to instal...

Page 7: ...PCB Theory of parts View of PCB Note This map is applies to 7201 model 7 Note This map is applies to 7207A model ...

Page 8: ...inlet valve RE Thermister ML Washing Pump PS Drain Pump D ED Dispenser EV1 Inlet valve EV2 Softener EV3 Halfload Valve ISS Salt detect ISB Rinse detect IAQS Overflow detect FM Flowmeter FAN Fan There is small pole s location difference between different models But the marks on PCB have the same meaning described on the left side 8 ...

Page 9: ...r into machine when it receive the order given by controller The defeat point 1 The valve coil is broken so the valve can t open It will cause the E1 error 2 The filter is jammed so water can t enter It will cause the E1 error 3 The connector is loose so the valve can t open It will cause the E1 error 4 The valve pole is rusted or locked by dreg so the valve can t open or close It will cause the E...

Page 10: ...ire EV1 and the blue wire ACN the normal resistance is about 3 4K to 4 4K 3 I f the measured resistance is not correct it means the valve coil is broken or the connector is loose In this case we should check the connection first If the problem hasn t been solved by re connection we should replace the valve 4 If the resistance is OK we need to inspect the valve body Ω Ω Ω Inspect inlet valve Check ...

Page 11: ...at point 1 The motor coil is broken so the drain pump can t work It will cause the E2 E4 or E1 error 2 The magnetism of motor rotor is weak so drain pump cannot work It will cause the E2 E4 or E1 error 3 The connector is loose so the drain pump can t work It will cause the E2 E4 or E1 error 4 The rotor is locked by residues so the drain can t work It will cause the E2 E4 or E1 error 5 The drain pu...

Page 12: ...hooks and be care do not break the hook 3 Label and disconnect the two terminal lugs from the drain pump 4 Contrarotate the drain pump to take it off 5 Reverse the above procedure to install Access drain pump Inspect drain pump Check the electric part 1 Open the protecting box and take out the PCB 2 With the door closed unplug the CON3 and ACN wires then use the multi meter shelf to measure the re...

Page 13: ...ve so the heater cannot work It will cause the E3 error 3 The connector is loose so the heater cannot work It will cause the E3 error Heater Theory of parts The work principle Technical data Location of Heater Nominal voltage 230VAC Rating power 1800W Resistance 29 4 10 Ω Fuse 167 13 Bottom view pressure switch fuse ...

Page 14: ...s the heater coil or the thermostat is broken we should replace the heating element or the thermostat Ω Ω Ω Heater Theory of parts Access heater 1 Drain off the water in the dishwasher and disconnect the power supply Note Make sure to remove remained water in the dishwasher If not wet the floor 2 Remove bottom board 3 Label and disconnect the terminals 4 Remove the 3 screws for fixing the heating ...

Page 15: ...It will cause E3 error 3 The connector is loose the wash pump can t work It will cause E3 error 4 The rotor is locked by residues so the wash pump can t work It will cause the E3 error 5 The drain pump assembly bracket is loose it will cause noise 6 If the machine hasn t been used for long time there is a possibility the wash pump can t starting M main coil A assistant coil Models Items YXW48 2F 1...

Page 16: ...ily damaged during removal and can t be reused Replace the old clamp with a new universal clamp 5 Disconnect the ground wire from the wash pump motor assembly 6 Remove the motor pump assembly from the dishwasher 7 Reverse above procedures to install Inspect Washing Pump Check the electric part 1 Open the control panel and take out PCB 2 With the door closed unplug the CON5 then use the multi meter...

Page 17: ...ated to trip and reset at the desired pressure levels The main application is to control the level of water in appliances May also provide flood protection In our production May also provide flood protection like 135 115 serial Back view Front view 1 COM 2 NC 3 NO Pressure Switch Theory of parts The work principle 17 2 1 3 ...

Page 18: ...ature Coefficient Thermistor is integrated into sump which is used for measuring temperature of water in the tub Access NTC 1 Remove bottom board 2 Remove two screws securing the NTC to sump shown in above picture 3 Take out NTC 4 Reverse the above procedure to install 18 ...

Page 19: ...d unplug the RE connector shown in below picture then use the multi meter shelf to test resistance between two blue wires RE and GND the normal resistance is shown in below table 3 I f the resistance is not correct it means NTC circuit has a problem In this case we should check the connection first If the problem hasn t been solved by re connection we would replace the NTC Ω NTC resistance table 1...

Page 20: ...into Air Breaker Function of Flowmwter is measure how much water has entered in appliance it consists of impeller tongue tube and terminal etc When water pass through the flowmeter moving water can rotate magnetic impeller the tongue tube can sense the impeller s magnetic and send electronic pulses 20 ...

Page 21: ...pulse the multi meter will not send sound In this case it means something wrong with flowmeter circuit We should check the connection first If the problem hasn t been solved by re connection we should replace the air breaker Access Flowmeter 1 Remove the baseboard top panel and left side panel 2 Remove the plastic nut inside tub which secures the air breaker to tub Because flowmeter is integrated ...

Page 22: ...fill the air space between two layers the foaming material will expand and lock the hose In this situation the machine might set off E1 alarm also has two layers But the difference from mechanical is that if the water leak and flow on the bottom tray the flooding pressure switch on the tray will act the electromagnetic valve on the hose will cut off the water road and the machine will set off E4 a...

Page 23: ...sal water inlet hose 1 Open the protecting box and take out the PCB 2 With the door closed unplug the CON3 and ACN wires then use the multi meter shelf to measure resistance between the blue wire EV1 and blue wire ACN Open circuit and short circuit are both incorrect 3 I f the measured resistance is not correct it means the valve coil is broken or the connector is loose In this case we should chec...

Page 24: ...n press Program button to jump into next step except inlet valve step Note The way to activate test program is slightly different between different models How to activate Test Program In order to check the operation of components of appliance and find out the malfunction we designed this program for technician Test Program 7311D 7312D How to activate Test Program With door opened Program Power Sta...

Page 25: ... 05 03 Description 88 Power on stand by Open inlet valve and feeds with 3 6L water 45cm model feeds with 3 0L water 04 Temper ature value Run higher speed washing pump and 10s later run heating element until the water temperature reaches 57 Then the machine will pause Press Start Pause button to jump into the next step F Buzz one sound stop and stand by 2s later run lower speed washing pump for 8s...

Page 26: ...seconds and the Glass 1 hour and Rapid indicators would flash simultaneously Other error alarms can be deduced from this The corresponding relation between indicator and error code shown in above figure Notice the majority of models are follow this regulation combination Priority level of E4 is the highest E4 operation is valid after other error operations have done When E4 operation has done all ...

Page 27: ... will be stopped immediately At the same time the buzzer will alarm for 30 seconds and the error 3 will be shown 27 E4 Overflow In test program once open circuit failure of thermistor is detected by controller the E6 would occur When E6 occurs the drain pump will run until flowmeter keep motionless for 2 minutes and all the other components will be stopped immediately At the same time the buzzer w...

Page 28: ...iverter valve for 15 seconds or doesn t detect the diverter valve being positioned accurately in 60 seconds the E8 would occur In the process of washing program in which diverter valve should be act if machine doesn t detect the feeding signal of diverter valve for 15 seconds or doesn t detect the diverter valve being positioned accurately in 60 seconds the diverter valve would stop and the E8 wou...

Page 29: ...Still wrong Replace the Inlet Valve to solve problem Check whether the Pressure Switch 83 63 circuit is correct or not Make a check of Inlet Hose solve the problem Inlet Hose is blocked or kinked OK Failure Failure Reconnect the wire of Pressure Switch circuit and check again Not solve the problem OK Replace the Pressure switch to solve problem Still wrong Make a check of inlet hose of AQUASTOP on...

Page 30: ...the wire of Heater circuit and check again OK Still wrong Replace the Inlet Valve to solve problem Check whether the Washing Pump circuit is correct or not mentioned in section 4 Reconnect the wire of Washing Pump circuit and check again Not solve the problem OK Replace the Washing Pump to solve problem Still wrong OK Reconnect the wire of NTC circuit and check again solve the problem OK Replace t...

Page 31: ...follows Remove two side panels Remove the water from the bottom board and make sure there is no water at the bottom board Restart the dishwasher with a strong or standard wash program as a leakage could easily repeat at a higher temperature and after a long period of running time Observe the bottom tray every twenty minutes If any water appears you will found out which areas such as motor drain pu...

Page 32: ...lowmeter circuit and check again Not solve the problem OK Replace the NTC to solve problem Still wrong If the problem has not been solved through all the inspection mentioned above maybe the PCB has a malfunction So replace PCB and test again Caution Because the real situation is unpredictable inspection trees mentioned in this manual are for reference only 32 E8 Diverter valve fault Check whether...

Page 33: ...Troubleshooting 33 ...

Page 34: ...Troubleshooting 34 ...

Page 35: ...Troubleshooting 35 ...

Page 36: ...Troubleshooting 36 ...

Page 37: ...Troubleshooting 37 ...

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