12V DC Liquid Level Sensor Relay Module – Auto Fill & Drain
12V DC Liquid Level Sensor Relay Module – Auto Fill & Drain
2-in-1 Automatic Drain & Fill Controller – 12V DC Liquid Level Sensor Relay Module
Take full control of your water management with this compact 2-in-1 Liquid Level Sensor Relay Module. Operating on 12V DC, this intelligent relay module automatically monitors and controls liquid levels — switching pumps, solenoid valves, and motors ON or OFF based on your preset high and low thresholds. Whether you're managing a home water tower, fish tank, livestock watering system, or an irrigation setup, this module delivers reliable, hands-free automation at an affordable price.
Made in Mainland China.
Key Features
- 2-in-1 Operation: Supports both automatic filling (pump water in) and automatic drainage (pump water out) modes — simply choose COM/NC or COM/NO wiring to match your setup.
- 12V DC Input: Wide operating range of DC 10–15V for flexible power supply compatibility.
- Low Power Consumption: Standby current of just 9 mA; operating current of 40 mA — energy-efficient for 24/7 use.
- High Load Capacity: Relay rated at 10A/250VAC, 10A/30VDC — handles most standard pumps and motors with ease.
- No Specialised Probe Needed: Use standard household wire to create your own probes — simple and cost-effective.
- Compact Design: Small footprint (44 × 29 × 19 mm) fits easily into enclosures and DIY control panels.
- Wide Application Range: Ideal for water towers, aquariums, farms, poultry systems, solenoid valve control, and more.
Technical Specifications
| Operating Voltage | DC 12V (DC 10–15V) |
| Standby Current | 9 mA |
| Operating Current | 40 mA |
| Dimensions | 44 mm × 29 mm × 19 mm |
| Maximum Load | 10A/250VAC · 10A/125VAC · 10A/30VDC · 10A/28VDC · 10A/12VDC |
Pin Reference
- HIGH – Upper limit sensor input
- OUT – Output sensor
- LOW – Lower limit sensor input
- DC+ – Positive power supply
- DC− – Negative power supply
- NC – Relay normally closed contact
- COM – Relay common contact
- NO – Relay normally open contact
How It Works
Auto-Fill Mode (COM/NC): When the water level drops below the LOW threshold, the pump activates and fills the tank. When the level rises above the HIGH threshold, the pump stops automatically.
Auto-Drain Mode (COM/NO): The reverse logic — the pump activates when the level rises above the HIGH threshold and stops when it drops below the LOW threshold.
Common Applications
- Home and residential water tower automation
- Aquarium and fish tank water change systems
- Farm and agricultural irrigation control
- Poultry and livestock automatic watering feeders
- Solenoid valve and motor control
- Any system requiring automatic liquid level management
What's in the Box
- Relay Module × 1
Note: Probe wiring is NOT included. Standard household wire can be used to create probes. For safety, always use a well-insulated DC power supply.
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Frequently Asked Questions
Q: Does the liquid level sensor relay module include probes?
A: No, the package does not include probes. However, no specialised probe is required — you can easily make your own probes using standard household electrical wire, keeping costs low and setup simple.
Q: Can this relay module be used for both filling and draining water tanks?
A: Yes! This is a 2-in-1 module. Connect your pump to the COM/NC terminals for automatic tank filling, or to the COM/NO terminals for automatic drainage — giving you full flexibility for different liquid management scenarios.
Q: Is this liquid level relay module suitable for aquarium fish tanks?
A: Absolutely. The module is commonly used for aquarium water change systems, automatically activating a pump when the water level drops below the LOW sensor point and stopping it when the HIGH sensor point is reached, making tank maintenance effortless.
Q: What power supply does the relay module require?
A: The module operates on 12V DC with a wide input range of 10–15V DC. Always use a well-insulated DC power supply for safe operation.
Production & Packaging Notice
To maintain high stock availability and fast shipping times, our items are sourced from multiple verified manufacturing facilities. While the core quality, materials, and product specifications remain identical, you may notice slight variations in the packaging design, manufacturing origin, or the wording of the printed instructions.