HX-SXD-P1.0A Instant Water Heater PCBA

YED-SXD-P1.0A Instant Electric Water Heater PCBA with 12–24 kW Parameter Settings

The YED-SXD-P1.0A is a customizable instant electric water heater PCBA developed for water-heating systems requiring wide-voltage operation, multiple heater-power settings, intelligent temperature control and integrated safety diagnostics.

The complete control solution consists of a YED-SXD-P1.0A power board based on an APT control platform and a 39A-5754KEY-V1.6 display board using a BYD control platform.

It integrates temperature adjustment, preset temperature modes, water-flow activation, inlet and outlet temperature monitoring, automatic temperature-control learning, parameter memory, display feedback and fault protection.

The hardware, firmware, display artwork, key layout and operating logic can be customized according to the customer’s appliance structure, heating element, electrical system and target market.

Key Specifications

Power Board Model: YED-SXD-P1.0A

Display Board Model: 39A-5754KEY-V1.6

Power Board Platform: APT-Based Control Solution

Display Board Platform: BYD-Based Control Solution

Power Supply Options: Transformer or Switch-Mode Power Supply

Transformer Input Voltage: 180–265 VAC

Switch-Mode Power Supply Input: 85–280 VAC

Temperature Setting Range: 30–55°C

Preset Temperatures: 38°C, 42°C and 45°C

Control Interface: Four-Key Touch Control

Control Functions: Mode, Temperature Down, Temperature Up and Power

Power Parameter Settings: 12, 14, 16, 18, 22 and 24 kW

Touch Panel Compatibility: 4 mm Glass Panel or 2 mm Plastic Panel

Temperature Sensor: 50K NTC

Flow Activation Threshold: 1.4 L/min

Heating Shutoff Threshold: 1.2 L/min

Water-Flow Switch: Four-Wire Flow Switch

Buzzer Frequency: 2.5 kHz

Operating Temperature: -15°C to 65°C

Operating Humidity: 10–95% RH

Wide-Voltage Power Supply Options

Two power-supply configurations are available for different appliance requirements.

The transformer-based configuration supports an input-voltage range of 180–265 VAC. During internal sample validation, it operated continuously at 265 VAC for eight hours without abnormality.

The switch-mode power supply configuration supports a wider input range of 85–280 VAC. The sample operated continuously at 280 VAC for eight hours without abnormality.

These configurations allow the control solution to be adapted to different regional voltage conditions, product structures and cost requirements. The appropriate power-supply design should be selected according to the target market and complete-appliance electrical specifications.

Configurable 12–24 kW Heater-Power Parameters

The firmware provides six heater-power parameter options:

- 12 kW

- 14 kW

- 16 kW

- 18 kW

- 22 kW

- 24 kW

While the controller is in standby mode, pressing and holding the Mode key for five seconds opens the power-setting menu. The Temperature Up and Temperature Down keys can then be used to select the required parameter.

The 12–24 kW values are software configuration parameters for matching different water-heater platforms. They do not represent the standalone load capacity of the PCBA.

The actual rated power and current capacity depend on the heating element, relay or power-control components, wiring, terminals, PCB copper design, thermal management and complete-appliance electrical system. Every project must be evaluated according to its final hardware configuration.

Flexible Temperature Control

Users can adjust the target temperature from 30°C to 55°C in 1°C steps. Three preset temperature modes—38°C, 42°C and 45°C—provide quick access to commonly used settings.

The four-key interface includes:

- Mode

- Temperature Down

- Temperature Up

- Power

Pressing and holding the Temperature Up or Temperature Down key for more than one second enables continuous adjustment. Every valid key operation produces one audible beep for clear user feedback.

Touch-Panel Compatibility

The touch-control interface can operate through a 4 mm glass panel or a 2 mm plastic panel. It supports individual light-touch operation without requiring sliding gestures.

The key arrangement, printed icons, display film, language, temperature presets and interface graphics can be customized to match the customer’s enclosure and brand design.

Intelligent Display Functions

When power is connected, the buzzer sounds once and all display segments illuminate for approximately one second. The display then shows the program information and configured heater-power parameter before entering the power-off state.

During operation, the display can show:

- Configured heater-power parameter

- Set water temperature

- Outlet water temperature

- Real-time water-flow status

- Heating status

- Dynamic shower or heating indicator

- No-flow indication

- Fault-code information

When no water flow is detected, the screen displays “--”. After water flow is detected, the controller can display the flow status and activate the relevant operating interface.

Water-Flow Activation and Heating Control

The reference heating activation threshold is 1.4 L/min. Heating stops when the water flow drops to approximately 1.2 L/min.

The sample uses a four-wire water-flow switch. The flow thresholds and sensor interface can be adapted after engineering evaluation according to the water path, heating power and required operating logic.

Inlet and Outlet Temperature Monitoring

The controller supports inlet and outlet temperature monitoring through 50K NTC temperature sensors.

Temperature feedback is used to coordinate water flow, heating power and outlet temperature. The controller can also inhibit relay operation when the detected inlet temperature reaches the minimum set temperature, helping prevent unnecessary heating.

Automatic Temperature Learning and Memory

The firmware supports automatic temperature-control learning and calibration. This function allows the controller to optimize its operating parameters according to the heating element, water flow, temperature feedback and thermal characteristics of the complete appliance.

The controller stores the selected temperature and heater-power settings. After the power supply is restored, the system defaults to the off state while retaining the previously configured parameters.

Sample Temperature-Control Performance

Temperature-control testing was performed with an inlet water temperature of 26°C and flow rates of 1.5 L/min and 3.0 L/min.

After completing the initial temperature-learning calibration, the sample reached a stable outlet temperature within 20 seconds under the recorded test conditions.

At a flow rate of 1.5 L/min:

- 30°C setting: measured at 29–31°C

- 36°C setting: measured at 35–38°C

- 40°C setting: measured at 39–41°C

- 45°C setting: measured at 44–47°C

- 48°C setting: measured at 47–50°C

At a flow rate of 3.0 L/min:

- 30°C setting: measured at 29–31°C

- 36°C setting: measured at 35–37°C

- 40°C setting: measured at 39–41°C

- 45°C setting: measured at 44–46°C

- 48°C setting: measured at 47–49°C

Actual temperature accuracy and stabilization time depend on inlet water temperature, flow rate, heater power, sensor position and complete water-path design. Final performance should be verified using the customer’s complete appliance prototype.

Integrated Safety Protection and Fault Diagnostics

The YED-SXD-P1.0A control solution provides multiple protection and fault-diagnostic functions.

E1 Over-Temperature Protection

When the detected water temperature reaches 63°C or above, the controller stops heating and activates an alarm. Heating resumes after the temperature falls to 50°C.

E2 Leakage-Current Protection

If a leakage-current fault is detected, the controller disables heating and activates an alarm. Normal operation can resume after the fault is repaired and the appliance is restarted.

The sample report specifies a leakage-detection range of 15–28 mA. The sample measured 22–24 mA using a two-wire leakage-detection coil. The final threshold must be matched to the leakage coil and complete-appliance safety design.

E3 Inlet Temperature Sensor Fault

An open or short circuit in the inlet temperature sensor activates an alarm. The controller requires a cold restart and temperature-control relearning after the fault is corrected.

E4 Outlet Temperature Sensor Fault

If the outlet temperature sensor is open or short-circuited, the controller disables heating and activates an alarm. It automatically recovers after the sensor fault is corrected.

E9 Communication Fault

A communication fault disables heating and activates an alarm. The controller can automatically recover after normal communication is restored.

The controller also supports leakage-circuit self-testing. The final fault-code definitions and recovery logic can be customized according to the customer’s firmware requirements.

Environmental and Reliability Validation

The specified operating temperature range is -15°C to 65°C, while the operating humidity range is 10–95% RH.

The sample completed the following internal tests:

- Eight hours of operation at 265 VAC with the transformer configuration

- Eight hours of operation at 280 VAC with the switch-mode configuration

- Eight hours of operation at 65°C and 90% RH

- Dielectric withstand testing at 1800 V and 5 mA for one minute

- Thirty fluorescent-lamp switching cycles at intervals of 0.5–3 seconds

- Normal-temperature water-change testing

- Circulating-water temperature-control testing

No abnormal operation was recorded during these sample tests.

These results represent internal sample validation. They should not be interpreted as independent EMC, electrical-safety or complete-appliance certification.

Typical Applications

This instant electric water heater PCBA is suitable for:

- Residential instant electric water heaters

- High-power instant water-heating systems

- Commercial point-of-use water heaters

- Hotel and apartment hot-water equipment

- Kitchen and washbasin water heaters

- Touch-control water heaters with glass or plastic panels

- Water-heating appliances requiring multiple power configurations

- Custom temperature-controlled heating equipment

OEM/ODM PCBA Development and Manufacturing

Foshan Shunde SunSam Electronic Co., Ltd. has 15 years of experience in custom PCBA development and manufacturing. Water heater control boards are one of our core product categories.

Our one-stop OEM and ODM services include:

- Product-function evaluation

- Hardware and firmware development

- Circuit and PCB design support

- Component sourcing

- Prototype manufacturing

- SMT assembly

- Wave soldering

- Firmware programming

- ICT and FCT testing

- Functional verification

- Material and production traceability

- Volume manufacturing

The input voltage, heater-power parameters, temperature range, preset modes, key layout, display content, sensor specifications, flow thresholds, protection functions and fault codes can be customized after engineering evaluation.

Start Your Custom Water Heater PCBA Project

Customers can provide an existing sample, BOM, Gerber files, schematic, enclosure drawing or functional specification for evaluation.

For an accurate technical proposal and quotation, please provide:

- Target-market voltage requirements

- Heating-element rated voltage and power

- Power-control method

- Required temperature range

- Water-flow sensor specifications

- Temperature-sensor specifications

- Display and key-layout requirements

- Enclosure dimensions

- Required testing standards

- Estimated order quantity

- Project schedule

Contact SunSam to discuss your instant electric water heater PCBA project. Our engineering and production teams can support development from initial evaluation and prototype testing to customized mass production.