Midea Fxx-22BA6 (HY) Storage Electric Water Heater Technical Service Manual

1. Overall Machine Overview

1.1 Buttons

There are 5 mechanical buttons. Refer to the button description section for specific operation instructions.

1.2 Display

Display screen: See display description.

Physical Unit

An image shows the Midea electric water heater with its control panel.

1.3 Product Features

• Appearance:
• 1. Circular appearance, with "midea" printed on the barrel.
• 2. Control panel and display are located at the bottom.
• Structure:
• 1. Cylindrical metal body with plastic end caps.
• 2. Inlet, outlet, and drain ports are located at the bottom.
• 3. Anti-electric wall cover is located at the water pipe position.
• 4. Control part and display are located on the anti-electric wall cover.
• 5. Power board is located on the right end mounting cover.
• Electronic Control:
• Function Buttons: Low energy standby, E+ capacity expansion, WiFi, temperature adjustment, power on/off.
• Display Screen: Dual 8-segment display for setting and actual temperature, with corresponding indicator lights.

1.4 Specifications and Technical Parameters

Product Basic Information

Product Specification Information

2. Component Names

3. Disassembly Procedure

The following steps detail the disassembly process, with accompanying images for reference.

1) Disassembly of Mounting Cover and Power Board:

• Use a triangular head screwdriver to remove the screws (see Photo 1).
• Open the mounting cover (see Photo 2). The power board shape may vary; refer to the actual product.
• Disconnect the connecting wires from the heater and temperature limiter to remove the mounting cover and power board (see Photo 3). The power board shape may vary; refer to the actual product.
• Use a Phillips head screwdriver to remove the screws fixing the power board, then remove the power board and mounting cover.

2) Disassembly of Heater and Temperature Limiter:

• Disconnect the connecting wires from the temperature limiter. Use a Phillips head screwdriver to remove the two screws indicated (marked with red circles) to remove the temperature limiter (see Photo 4).
• Use a socket wrench to remove the five nuts indicated (marked with green circles), remove the heater flange, and then remove the heater (see Photo 5).

3) Disassembly of Anti-electric Wall Cover Assembly:

• Use a Phillips head screwdriver to remove the three screws connecting the anti-electric wall cover to the outer shell as shown in the diagram (see Photo 6).
• Disconnect the display board ribbon cable from the machine's internal wiring (marked with red circles). Then remove the anti-electric wall cover assembly (see Photo 7).

4) Removal of Display Board:

• Remove the cover from the disassembled anti-electric wall cover assembly (see Photo 8).
• Use a Phillips head screwdriver to remove the two screws indicated in the position shown.
• Remove the display board (see Photo 9).

5) Removal of Anti-electric Wall Pipes and Drain Plug (including Magnesium Rod Assembly):

• Use a socket wrench or adjustable wrench to remove the anti-electric wall inlet and outlet pipes as shown in the diagram (see Photo 10).
• Use a socket wrench to remove the drain plug as shown in the diagram (see Photo 11).

4. Operation Methods and Electronic Control Functions

4.1 Button and Function Summary Table

Fxx-22BA6 (HY) Electric Water Heater

4.2 Basic Composition and General Requirements

Mainly composed of:

• ☑ Power Board
• ☑ Display Board
• ☑ Remote Control

4.3 Display Content and Main Function Modes

1. LED display content and system configuration functions include:

2. Machine panel display content (as shown in the figure):

Fxx-22BA6(HY) Display Panel

An image shows the control panel of the Midea electric water heater with various indicators and controls.

4.4 Basic Parameters and Requirements

1. Rated operating voltage: AC220V/50Hz
2. Rated power of the whole machine: 2100W (-10% ~ +5%)
3. Heating tube power: Single tube 2200W
4. Applicable voltage: AC170V~270V/50Hz
5. Electrical strength: 2500VAC, 5mA, 1min
6. Operating environment temperature: -10℃~70℃
7. Relative humidity: 95% (at 25℃)
8. Storage temperature range: -40℃~80℃
9. Temperature setting range: Tmin~75℃, where Tmin is as follows: 30°C, 35°C, 40°C, 45°C
10. Dry burning slope determination: ≥8℃/30S or ≥15℃/60S
11. Timing accuracy: ≤3S/24h
12. Temperature measurement error: ±2℃
13. Flow error: ±0.25L/min (This model has no water flow sensor)
14. Temperature hysteresis: For models without instant heating function.

When the set temperature is ≤50℃, the temperature hysteresis is 5℃; when the set temperature is >50℃, the temperature hysteresis is 10℃.

The back of the circuit board must be coated with moisture-proof paint.

15. The circuit board must undergo at least 2H of aging at the factory.

4.5 Button and Display Specific Function Requirements

• "Power" Button

This button is for turning the unit on/off. When connected to power, the display will light up for 2 seconds, then display the version number (01) for 1 second. If there is a power-off memory function, it will restore the working state before the power outage. Otherwise, it will enter the shutdown state, and the digital screen will turn off.

1. In the power-on state, press the "Power" button. The buzzer will sound once, the system will shut down, the scheduled mode will be canceled, and the power-off memory data will be saved.
2. In the power-off state, press the "Power" button. The buzzer will sound once, the system will turn on, restore the power-off memory data, and enter the corresponding working state.

Note: The "Power" button has the highest priority among all buttons. Regardless of the system's working state, pressing the "Power" button will shut down the system. (Note: If in sleep or fault mode, pressing the power button will wake it up; in fault mode, pressing the power button is invalid).

• "Adjust" Button

1. Adjusting the set temperature: The set temperature can be cycled between (Tmin)-(Tmin+5)-(Tmin+10)...75-(Tmin). Each press of the "+" button increases the temperature by 5℃. If the button is held down, the temperature will increase at a rate of 25℃/sec. If no button is pressed for 5 seconds, the system will save the set temperature and exit the temperature setting state.
2. Adjusting the time: Adjust the scheduled setting time. Refer to the scheduled function for specific operations.

• "Schedule" Button

In non-scheduled mode, pressing this button adjusts the scheduled time. In scheduled mode, pressing this button exits the scheduled mode. Refer to the detailed description of the scheduled function for specific operations.

• "Mode" Button

In the power-on state, pressing this button cycles through E+ capacity expansion, high-temperature sterilization, and user mode. The corresponding indicator light will illuminate (no indicator light for user mode).

• "Variable Frequency Rapid Heating" Button

In non-scheduled mode, pressing this button cycles through power levels: 1300W - 2100W - 1300W - ... The corresponding indicator light will illuminate.

• E+ Capacity Expansion Function

In the power-on state, pressing the "Mode" button enables or disables the E+ capacity expansion function. When enabled, the E+ capacity expansion indicator light will illuminate; otherwise, it will turn off.

In E+ capacity expansion mode, the set temperature is fixed at 75℃ and cannot be adjusted. When the inner tank temperature is below 70℃, the displayed temperature reflects the actual inner tank temperature. When the inner tank temperature is between 71℃ and 80℃, the displayed temperature increases by 1℃ for every 2℃ rise in inner tank temperature. For example, 71℃ displayed corresponds to 72℃ in the tank, and 75℃ displayed corresponds to 80℃ in the tank. When the system switches from E+ capacity expansion mode to another mode (such as user mode), if the actual inner tank temperature exceeds 75℃, it will display 75℃. If the actual inner tank temperature is below 70℃, it will display the actual inner tank temperature. Note: The default maximum inner tank temperature in E+ capacity expansion mode is 80℃, but due to residual heat from the heating element, the actual inner tank temperature may exceed 80℃, which is normal.

• High-Temperature Sterilization Function

1. In high-temperature sterilization mode, the set temperature is 80℃. Pressing the "Mode" button will exit high-temperature sterilization mode and enter user mode.
2. In high-temperature sterilization mode, the temperature cannot be adjusted. If the user presses the "+/-" button, the high-temperature sterilization icon will flash for 3 seconds, but the mode will not be exited.
3. High-temperature sterilization and scheduled modes cannot be used simultaneously.

A) If a schedule is set, pressing the "Mode" button will enter high-temperature sterilization mode, cancel the schedule, and enter high-temperature sterilization mode.

B) In high-temperature sterilization mode, pressing the "Schedule" button will exit the sterilization mode and enter user mode, responding to the schedule.

4. If the unit exits high-temperature sterilization mode due to dry burning or a 5-minute delay after reaching the target temperature, it will return to user mode. If the "Mode" button is used to exit high-temperature sterilization mode, it will enter user mode. Note: The default maximum inner tank temperature in sterilization mode is 80℃, but due to residual heat from the heating element, the actual inner tank temperature may exceed 80℃, which is normal.

• Scheduled Bathing Function

In the power-on state, pressing the "Schedule" button will enter the scheduled time adjustment state, and the schedule indicator light will illuminate. The scheduled time can then be adjusted. After the scheduled time is set, the system will automatically calculate the preheating time based on the temperature difference and enter the scheduled waiting state. After the scheduled waiting period, the system will enter the heating/standby state, and the schedule will be exited.

4.6 Detailed Function Description

• Heating/Standby Function

The system determines the heating/standby state based on the difference between the actual temperature and the set temperature, and illuminates the corresponding indicator light (if the water heater is heating, the "Heating" indicator light is red; if the water heater is in standby mode, the "Standby" indicator light is green). In standby mode, if the difference between the actual temperature and the set temperature exceeds the temperature hysteresis, the unit will reheat.

• Delayed Scheduling

For models without Beijing time function, delayed scheduling is used, indicating that hot water will be available after "XX" hours. In the scheduled setting state, the user can press the "+" or "-" button to cycle through the scheduled hours from "01-02...-24-01". After setting the scheduled time, if no button is pressed for 5 seconds, the system will save the scheduled time parameters and enter the scheduled waiting process. During the scheduled waiting process, the actual temperature will be displayed. After the scheduled waiting period, the system will enter the scheduled preheating process, during which the actual temperature will be displayed. After the scheduled preheating process is completed, the system will enter the "Heating/Standby" process.

Figure 1: Scheduled Function Operation Diagram

An illustration shows the flow of the scheduled function.

Notes:

1. The minute part of the scheduled time cannot be set with any scheduling method.
2. The scheduled time can be adjusted using the "Adjust" button. If any other button is pressed while the scheduled time is flashing, the system will respond to the new button's function.
3. From the time the scheduled time is set until before scheduled heating, the user can adjust the temperature. After each adjustment, the system will recalculate the preheating time.
4. Inner tank capacity and heating tube heating rate are shown in the following table:

Scheduled Capacity Selection Table

The time required to raise the temperature by one degree Celsius for different capacities is shown in the following table (Power: 2100W):

The time required to raise the temperature by one degree Celsius for different capacities is shown in the following table (Power: 1300W):

• Automatic Sleep Function

When the system is in standby mode and no buttons are pressed for 3 minutes, the system will automatically enter sleep mode. The display will only show the current inner tank temperature, and the corresponding working indicator lights and set temperature will not be displayed. During sleep mode, pressing any button or initiating heating will cancel sleep mode. Note: The scheduled mode does not have a sleep function.

• Power-off Memory Function

The system has a power-off memory function that remembers the system's working state, set temperature, and other relevant information before a power outage. When power is restored, the system will automatically return to the working state before the power outage.

• Factory Setting Function

• Factory Setting via Buttons

When the unit is off, simultaneously press and hold the "Schedule" and "Power" buttons for 2 seconds. The display will light up completely, and the system will enter the factory setting mode (if there is a buzzer, it will beep continuously). After 2 seconds, the system will enter the shutdown state. The factory setting parameters are as follows:

• Inner Tank Capacity Setting

When the unit is off, simultaneously press and hold the "Schedule", "Adjust", and "Power" buttons for 2 seconds to display the inner tank capacity (in liters). The display will show the current inner tank capacity (e.g., 50L will display 50, 60L will display 60, 100L will display AO). Press the "Adjust+" button to modify the inner tank capacity. Press and hold "Schedule", "Adjust", and "Power" buttons for 2 seconds again (or if no button is pressed for 5 seconds) to confirm the capacity and exit the inner tank capacity setting mode. Once the inner tank capacity is set via buttons, the capacity detected by the jumper will no longer be effective.

• Anti-freeze Protection Function

When the unit is not heating and the water temperature in the water heater is ≤6℃, the corresponding heating element will be activated for heating.

• Heating Element P1

When the water is heated to 10℃, the heating will stop (the heating status will not be displayed, indicating a hidden heating mode).

4.7 Control Board Self-Check Function

Simultaneously press and hold the "Self-Check" button for more than 1 second when the unit is powered on. The system will enter the control board self-check mode. The control board will first display all segments for 1 second, then display the dual-color lights separately. It will also detect the inner tank capacity detection circuit, memory chip circuit, and the connection status of various interfaces with the power board. If there is an abnormality, the corresponding fault code will be displayed as follows:

• If the inner tank capacity detection circuit is abnormal, the display board will show E1.
• If the voltage of the 3rd pin of the connection interface between the inner tank and the power board is abnormal, the display board will show E3.
• If the voltage of the 4th pin of the connection interface between the inner tank and the power board is abnormal, the display board will show E4.
• And so on...
• If the voltage of the 9th pin of the connection interface between the inner tank and the power board is abnormal, the display board will show E9.
• If the voltage of the 10th pin of the connection interface between the inner tank and the power board is abnormal, the display board will show EA.
• If the voltage of the 11th pin of the connection interface between the inner tank and the power board is abnormal, the display board will show Eb.

If the memory chip circuit is abnormal, the display board will show EE.

If the clock chip circuit is abnormal, the display board will show EF.

If everything is normal, it will display 00. Then, it will detect the display board buttons. If one button is pressed, it will display 01. If two buttons are pressed simultaneously, it will display 02, and so on. Finally, pressing any button on the remote control will turn off the display, and pressing any button on the remote control again will restore the display. The system will automatically exit the self-check mode after 60 seconds. Note: This function requires specific testing equipment.

Workshop Self-Check:

When the unit is powered on, press the middle button on the remote control within 12 seconds to enter the power self-check mode. For the first 2 seconds, the 800W heating element will be connected. After another 7 seconds, the other 1300W heating element will be connected. After 9 seconds, all relays will be turned off.

4.8 Alarm Function and Fault Self-Check (Not applicable to empty shell units)

When a dry burning fault, over-temperature fault, sensor open circuit, or short circuit fault occurs, the digital tube on the display screen (the digital tube used for displaying hours) will flash E2, E3, or E4 respectively. Other digital tubes and indicator lights will not display anything. If there is a buzzer, it will sound 6 short beeps. All relays will be disconnected, and all buttons will be inoperable. After the fault is cleared and the unit is powered on again, the water heater will return to the shutdown state. When the unit is powered on, it will automatically perform a self-check. If a fault is detected, the corresponding fault code will be displayed, and the system will not operate (i.e., the water heater cannot be started).

4.9 Other Technical Requirements

1. The external dimensions, mounting dimensions, component height, and signal lines between the control board and power board shall comply with the corresponding drawings. The control board and power board shall have good interchangeability when matched. The circuit board material shall be 1.6mm thick flame-retardant epoxy board with moisture-proof treatment. The entire control system shall undergo aging treatment before leaving the factory.
2. When laying out the PCB board, the creepage distance shall meet the relevant standard requirements, and no wiring is allowed within 3mm of the positioning holes.
3. Key components must have CCC certification or CQC certification. The main chip must have strong anti-interference capability and be from a reputable manufacturer.
4. The circuit board must pass the corresponding EMC test, with standards referring to GB 4706.1-2005 and GB 4343.2-2009 for electromagnetic compatibility test, high-speed transient pulse group immunity test.
5. The detection standards shall comply with "Midea Electric Water Heater Electronic Control Board General Technical Requirements".

4.5 Parts List

Links to parts lists:

• F50-22BA6.xls
• F60-22BA6.xls
• F80-22BA6.xls

Exploded View

• Fxx-22BA6 (HY) Exploded View.pdf