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Product Model:
RSQ-52LBBoard Configuration:
Integrated Control/Display Board with Separate TRIAC ModulePower Supply Design:
Transformer-Based Power SupplyOperating Voltage:
AC 85–280 VOperating Frequency:
50/60 HzHeating Power Levels:
Three Heating Power SettingsTemperature Setting Range:
20–55°CActivation Flow Rate:
0.9–1.1 L/minDeactivation Flow Rate:
0.8 L/minTouch Panel Compatibility:
4 mm Glass or 2 mm Plastic PanelOperating Temperature:
−15°C to 65°COperating Humidity:
10%–95% RH
Buy a low-flow water heater control solution developed for compact showers, household hot-water appliances and customized heating equipment. SUNSAM combines water heater control experience, hardware development, firmware support and PCBA production under one manufacturing system.
The RSQ-52LB Anti-Freeze Instant Electric Water Heater PCBA combines an RSQ-52LB integrated control and display board with an RSQ-45-B2 TRIAC power module. A transformer-based power architecture, three heating-power settings, digital temperature control, low-flow activation and automatic anti-freeze control support practical household appliance designs.
The selected transformer power supply configuration supports AC 180–265 V. Sample testing also confirmed normal operation at 50 Hz and 60 Hz, providing flexibility for different regional mains-frequency requirements.
Continuous high-voltage validation covered eight hours of operation at AC 265 V without abnormal performance. High- and low-voltage functional checks from AC 180 V to 250 V also passed.
Three programmed power settings allow manufacturers to configure the controller for different heater ratings:
- P3: 3.5 kW
- P4: 4.5 kW
- P5: 5.5 kW
A protected long-press sequence opens the power-setting interface, reducing accidental changes during normal use. The selected level appears briefly during startup for quick production and service confirmation.
Power values refer to PCBA control settings. Final appliance ratings depend on the connected heater, conductor size, terminals, protective devices, water channel and thermal construction.
The user interface uses a Power key and a Cyclic Heating key. A simple two-key layout supports clean front-panel designs and straightforward daily operation.
Touch sensitivity supports installation behind 4 mm glass or 2 mm plastic. Manufacturers can select a panel material according to product appearance, target cost and enclosure requirements.
The temperature setting range covers 20–55°C with 1°C adjustment steps. A default startup setting of 38°C provides a practical starting point for common household hot-water applications.
Automatic constant-temperature calibration and parameter memory help retain learned control values. Temperature regulation uses water temperature, flow input and selected power level to manage the heating process.
A 50 kΩ NTC sensor at 25°C is specified for temperature measurement.
Heating activation occurs at approximately 0.9–1.1 L/min. Heating stops when flow falls to approximately 0.8 L/min. Such low activation requirements support compact heaters installed in locations with moderate water pressure or limited flow.
When maximum available power cannot raise outlet water to the selected temperature, the controller can display an LL warning after approximately 30 seconds. The LL code alternates with the measured outlet temperature, helping users recognize an excessive-flow condition.
Automatic anti-freeze control operates during standby under low-temperature conditions. The controller periodically activates the heating circuit to help protect the internal water chamber from freezing. An hd status code appears while anti-freeze operation remains active.
Exact anti-freeze activation parameters can be customized and confirmed during final engineering validation for the selected heater structure and target market.
A startup sequence illuminates the full display, shows the selected power level and presents the software version. A default temperature of 38°C then appears for normal operation.
During heating, the screen shows actual outlet temperature. Water-flow information can also appear on the display. A “--” symbol indicates no detected water flow.
The screen turns off after approximately 30 seconds without key input.
Multiple diagnostic functions support safer operation and faster servicing:
- Ht: Overtemperature protection
- E0 steady: Outlet temperature sensor short circuit
- E1 steady: Outlet temperature sensor open circuit
- E1 flashing: Inlet temperature sensor open circuit
- E0 flashing: Inlet temperature sensor short circuit
- E9: Communication fault
- LL: Excessive water-flow warning
- hd: Anti-freeze operating status
Overtemperature protection stops heating above 60°C and resumes heating after outlet temperature falls to 50°C. Inlet and outlet sensor faults stop heating and allow automatic recovery after fault removal.
Final safety performance depends on complete appliance construction, grounding, leakage protection, wiring, insulation and required market certification.
Sample testing used inlet water at approximately 28°C. Test settings covered 36°C, 40°C, 45°C and 48°C at flow rates of 1.5 L/min and 3.0 L/min.
At 1.5 L/min, measured temperatures reached 35–36°C, 39–40°C, 44–45°C and 47–48°C. At 3.0 L/min, measured temperatures reached 35.5–36.5°C, 39–40°C, 44–46°C and 47–49°C.
Recorded stabilization times ranged from 4 to 22 seconds across tested conditions. Performance can vary with inlet temperature, selected power, mains voltage, flow stability, sensor mounting and complete heater construction.
The sample report records an operating-temperature range from −15°C to 65°C and a humidity range from 10% to 95% RH. High-temperature and high-humidity validation included eight hours at 65°C and 90% RH without abnormal operation.
Additional validation covered repeated power switching, variable inlet-water tests and whole-appliance dielectric testing at 1,800 V, 5 mA for one minute. Recorded results represent sample-level validation rather than independent product certification.
Recommended applications include compact instant shower heaters, wall-mounted bathroom heaters, household washbasin heaters, apartment hot-water equipment and customized export-market appliances.
Low-flow activation benefits installations with moderate supply pressure. Automatic anti-freeze control supports products intended for colder environments, subject to final appliance-level verification.
SUNSAM provides hardware design, firmware development, component sourcing, PCB assembly, programming and functional testing for customized water heater control projects.
Available engineering changes can cover temperature ranges, power profiles, display content, button logic, sensor parameters, flow thresholds, anti-freeze logic, connector definitions and enclosure-matching requirements.
SUNSAM has 15 years of custom PCBA manufacturing experience. Instant electric water heater PCBAs account for about 70% of current production output, supporting focused engineering knowledge and established manufacturing processes.
Production resources cover SMT assembly, DIP insertion, wave soldering, programming, inspection and functional testing. Material traceability and in-process quality checks support stable batch consistency.
Engineering samples, pilot production and volume orders can follow confirmed project schedules. Material inventory and production capacity are arranged according to purchase orders and customer forecasts.
The controller combines transformer-based wide-voltage operation, three power levels, 20–55°C adjustment, low-flow activation, anti-freeze protection, digital display and multiple diagnostic functions.
An integrated control board and separate TRIAC module provide a practical architecture for customized household heater projects. Configurable firmware gives appliance manufacturers room for differentiated functions and user interfaces.
Explore more available solutions on the [SUNSAM Instant Electric Water Heater PCBA product page](https://www.sunsampcba.com/products.html).
Send SUNSAM the required voltage, heater power, temperature range, flow conditions, display design, sensor parameters and estimated order quantity. The engineering team can review the application and prepare a technical proposal for the RSQ-52LB Anti-Freeze Instant Electric Water Heater PCBA.
The selected transformer-based configuration supports AC 180–265 V. Sample testing confirmed 50 Hz and 60 Hz operation.
Available programmed settings include 3.5 kW, 4.5 kW and 5.5 kW. Final appliance power requires confirmation against the selected heater, TRIAC module, wiring and thermal design.
Users can select temperatures from 20°C to 55°C in 1°C steps. The default startup temperature is 38°C.
Heating starts at approximately 0.9–1.1 L/min and stops near 0.8 L/min. Final flow performance depends on hydraulic construction and flow-sensor calibration.
Available functions include overtemperature protection, inlet and outlet sensor fault detection, communication fault indication, excessive-flow warning and automatic anti-freeze control.
Yes. SUNSAM can evaluate customized hardware, firmware, power settings, display layouts, key functions, temperature logic, flow thresholds, sensors, connectors and anti-freeze control for OEM and ODM projects.
Address
Phase I of TianfuLai International Industrial City, Rongui Town, Shunde District, Foshan City, Guangdong Province, China
