Model: FS28-50W | Brand: FREESEA
Thank you for choosing the FREESEA FS28-50W Aquarium Heater. This submersible heater is designed to maintain a stable temperature in your aquarium, suitable for 1-10 gallon freshwater, saltwater, betta, and turtle tanks. Please read this manual thoroughly before installation and operation to ensure safe and optimal performance.
The FREESEA FS28-50W Aquarium Heater features an external temperature controller for easy adjustment and a digital LED display for real-time temperature monitoring. It includes multiple safety features to protect your aquatic environment.

Figure 1: FREESEA FS28-50W Aquarium Heater. This image displays the main unit of the heater with its digital temperature display, connected to the power cord and external controller. A betta fish is shown in the background, indicating its intended use.

Figure 2: Digital Display and External Controller. This image highlights the LED digital temperature display on the heater unit and the external controller with its 'SET' button and power indicator light. It shows how to adjust the temperature.

Figure 3: Double Safety Protection. This image illustrates the auto power-off feature (E1 error when out of water) and overheating protection (E2 error when temperature exceeds 95℉), showing the internal components and safety mechanisms.
| Feature | Detalje |
|---|---|
| Modelnummer | FS28-50W |
| Magt | 50 watt |
| Voltage | 110-120V |
| Frekvens | 60 Hz |
| Temperaturområde | 17℃ - 34℃ (63℉ - 94℉) |
| Anbefalet tankstørrelse | 1-10 liter |
| Heater Dimensions (approx.) | 4.7 x 2.6 x 1.4 tommer |
| Strømkabellængde | 5 feet (approx. 6.5 feet total length including controller) |
| Materiale | Glass (heating element), Plastic (housing) |
| Varens vægt | 8.1 ounce |

Figure 4: Installation Methods. This diagram illustrates correct (fully submerged, vertical or horizontal) and incorrect (partially submerged, controller in water) installation positions for the heater.
| Problem | Mulig årsag | Løsning |
|---|---|---|
| Heater not turning on / No display | No power, faulty outlet, damaged cord. | Check power connection. Test outlet with another device. Inspect power cord for damage. |
| Display shows "E1" | Heater is not fully submerged in water. | Ensure the heater is completely underwater. If water level is low, add water to the tank. |
| Display shows "E2" | Overheating protection activated (water temperature above 94℉ / 34℃). | Check actual water temperature with a separate thermometer. If too high, unplug the heater and allow water to cool. Ensure proper water circulation around the heater. |
| Water temperature fluctuates significantly | Poor water circulation, heater too small for tank, external factors (room temperature). | Ensure good water flow around the heater. Verify heater wattage is appropriate for tank size. Minimize external temperature fluctuations. |
| Heater not reaching set temperature | Varmelegeme wattage insufficient for tank size/temperature difference, faulty unit. | Confirm heater wattage is suitable for your tank (50W for 1-10 gallons). Allow sufficient time for heating. If problem persists, contact customer support. |
FREESEA is committed to providing high-quality products and excellent customer service. If you encounter any issues with your FREESEA FS28-50W Aquarium Heater or have questions regarding its operation, please do not hesitate to contact our professional after-sales service team.
For warranty details and support, please refer to the contact information provided with your purchase or visit the official FREESEA website. Our team is available to assist you with any concerns.
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