1. Introduction
Thank you for choosing the hygger HG252 250W Submersible Aquarium Heater. This heater is designed to provide a stable and consistent temperature for your aquatic environment, suitable for 35-45 gallon tanks. It features a digital display controller, run-dry protection, and overheating protection to ensure the safety and well-being of your aquatic inhabitants. Please read this manual thoroughly before installation and operation to ensure proper use and longevity of the product.
2. Safety Instructions
- Always ensure the heater is fully submerged in water before connecting it to a power source.
- The external controller is not waterproof. Keep it dry and away from water splashes.
- Do not operate the heater if the power cord or plug is damaged.
- Unplug the heater from the power outlet before performing any maintenance, cleaning, or when handling the aquarium water.
- The heater features built-in run-dry protection, which automatically shuts off the heater and displays an "Er" error code if not submerged.
- Overheating protection activates if the water temperature reaches or exceeds 95°F (35°C), shutting off the heater and displaying an "EE" error code.
- The plastic casing protects fish from direct contact with the heating element, preventing burns.
- Ensure the heater is securely attached to the aquarium glass using the provided suction cups.
- This product is for indoor use only and intended for aquariums.
Figure 2.1: Triple Safety Features. This image highlights the impact-resistant ABS shell, which prevents fish from contacting the heating element. It also shows the run-dry protection (displaying 'Er' when out of water) and overheating protection (displaying 'EE' when temperature exceeds 95°F).
3. Product Features
- Accurate and Reliable: Built-in run-dry and over-heating protection sensors automatically shut off the heater when not submerged or if water temperature reaches 95°F (35°C), displaying error codes for safety.
- Consistent Environment: Utilizes 3mm thick, shatter-resistant quartz glass and nickel alloy heating wire for stable, fast heat distribution, maintaining optimal water temperature.
- Precise Adjustable Temperature Control: External thermostat controller allows temperature adjustment between 59-93°F (15-34°C) in 1°F increments without getting hands wet.
- Strong, Detachable Protective Casing: The heater casing protects fish from direct contact with the heating element and safeguards the heater from accidental impacts. It is easy to detach for cleaning.
- Compact Design: Small footprint (5 x 3 x 1.1 inches) allows for easy concealment in corners or behind decorations.
- Digital Display: Easy-to-read digital display shows current and set temperatures. Red indicator light for heating mode, green for standby.
- Memory Function: Remembers and restores previous temperature settings after a power cut.
Figure 3.1: Internal Components and Design. This image provides an exploded view, detailing the nickel-chromium heating wire for fast heating, dual explosion-proof quartz glass heating tubes, the solid ABS shell for protection, and the two strong suction cups for secure placement.
4. Package Contents
- 1 x hygger HG252 250W Submersible Aquarium Heater
- 2 x Suction Cups (pre-attached)
- 1 x User Manual
5. Setup and Installation
- Placement: Position the heater fully submerged in your aquarium. Ensure it is placed in an area with good water circulation for even heat distribution.
- Mounting: Use the two strong suction cups to securely attach the heater to the inside wall of your aquarium. Ensure the heater is positioned vertically or horizontally, but always fully submerged.
- Controller Placement: Place the external temperature controller in a dry location, away from water.
- Power Connection: Once the heater is securely installed and fully submerged, plug the power cord into a suitable electrical outlet.
Figure 5.1: Installation for Various Aquarium Types. This image illustrates proper heater placement (vertical, tilted vertical, horizontal) ensuring full submersion. It also shows incorrect placements such as out of water, buried in substrate, or upside down, which should be avoided.
6. Operating Instructions
- Power On: After plugging in, the digital display on the controller will show the current water temperature.
- Setting Temperature: Use the buttons on the external controller to adjust the desired temperature. The adjustable range is 59-93°F (15-34°C). Press the button to cycle through temperature settings.
- Indicator Lights:
- A red light indicates the heater is actively heating the water.
- A green light indicates the heater is in standby mode, maintaining the set temperature.
- Memory Function: In case of a power outage, the heater will remember your last set temperature and resume operation once power is restored.
Figure 6.1: External Temperature Control and Clear Display. This image illustrates the external controller, showing how to set the temperature and interpret the digital display. It highlights the red light for heating mode, green light for standby mode, real-time water temperature display, and the memory function.
7. Maintenance
- Regular Cleaning: Periodically clean the heater to prevent algae and mineral buildup, which can affect its efficiency.
- Detaching Casing: To clean, first unplug the heater. Hold the heater with your left hand and press down, while lifting the top shell with your right hand to detach the protective casing.
- Cleaning Elements: Gently clean the quartz glass heating tubes and the protective casing with a soft brush or cloth and aquarium water. Do not use harsh chemicals or abrasive materials.
- Reassembly: After cleaning, reattach the protective casing by aligning it and pressing it firmly until it clicks into place.
- Submersion: Ensure the heater is fully submerged before plugging it back into the power outlet.
Figure 7.1: Easy to Detach & Clean. This image demonstrates the simple process of detaching the protective casing for thorough cleaning of the heating elements. It emphasizes that the controller is not waterproof.
8. Troubleshooting
| Problem | Possible Cause | Solution |
|---|---|---|
| Heater not turning on / No display | No power supply; Loose connection; Power outage. | Check power outlet; Ensure plug is fully inserted; Verify power supply. |
| Display shows "Er" | Heater is not fully submerged (Run-dry protection activated). | Unplug the heater, ensure it is fully submerged in water, then plug it back in. |
| Display shows "EE" | Water temperature exceeds 95°F (35°C) (Overheating protection activated). | Unplug the heater, allow water to cool naturally, or perform a partial water change with cooler water. Re-plug when temperature is safe. |
| Heater not heating / Red light not on | Set temperature is lower than current water temperature; Heater malfunction. | Increase the set temperature; If problem persists, contact customer support. |
| Temperature fluctuation | Poor water circulation; Heater placed in an area with uneven temperature. | Ensure good water flow around the heater; Relocate heater to a more central area if possible. |
9. Specifications
| Feature | Specification |
|---|---|
| Model Number | HG252 |
| Power | 250W |
| Recommended Tank Size | 35-45 Gallons |
| Control Range | 59-93°F (15-34°C) |
| Temperature Accuracy | ±2°F |
| Heater Dimensions | 5 x 3 x 1.1 inches (approx.) |
| Cord Length | 2.6ft (heater to controller) + 4.2ft (controller to plug) |
| Material | Quartz Glass, ABS Plastic |
| Protection Features | Run-dry protection, Overheating protection |
Figure 9.1: Compact Size and Specifications. This image visually represents the heater's small dimensions and summarizes key specifications such as model, power, control range, temperature accuracy, suitable aquarium sizes, and cord length.
10. Warranty and Support
For warranty information, please refer to the documentation provided with your purchase or contact your retailer. If you encounter any issues or have questions regarding your hygger HG252 aquarium heater, please contact hygger customer support through their official website or the platform where the product was purchased.
