Compact Liquid Level Control for Tanks, Pumps and Industrial Water Systems
The THV-3 Round Flat Float Switch is designed for simple, reliable liquid level control in water tanks, pump systems, drainage pits, sewage applications and industrial equipment. With its round flat body, the switch is easier to fit into compact spaces where a bulky float may not move freely.
When the liquid level rises or falls, the float changes angle and sends an ON/OFF signal to the control circuit. This makes it suitable for automatic pump start/stop, overflow protection, low-level alarm and basic liquid level monitoring.
Unlike triangular or rectangular float switches, the THV-3 focuses on a low-profile round design. It is a practical choice for customers who need a neat, compact float switch for tanks, sumps and OEM equipment.
Why Choose a Round Flat Float Switch?
In many tanks or pump systems, the float switch must move smoothly without touching the tank wall, pipe, pump body or other internal parts. A round flat structure helps reduce installation interference and gives the float a clean movement path.
The THV-3 is especially useful when buyers want:
A compact float switch for limited tank space
A clean round appearance for OEM equipment
A simple ON/OFF liquid level control solution
A float switch for water, drainage or light wastewater applications
Flexible cable length for different installation depths
Reliable pump control without complicated calibration
Key Features
Round Flat Body Design
The THV-3 uses a round flat float body that is easy to install in tanks, water containers, pump pits and small equipment housings. The compact profile helps the switch move naturally with the liquid level.
Automatic Pump Control
The switch can be used to control pump start and stop according to the liquid level. It helps prevent dry running, overflow and unnecessary manual operation.
NO/NC Control Options
Depending on the wiring method and control requirement, the float switch can be used for filling control, draining control, high-level alarm or low-level alarm.
IP68 Waterproof Protection
The switch body is designed for long-term use in liquid level control environments. IP68 protection helps ensure stable operation in submerged or wet conditions.
Flexible Cable Length
Standard and customized cable lengths are available, such as 1m, 2m, 3m, 5m, 10m, 15m and 20m. Longer or shorter cables can be supplied according to project needs.
Easy Installation with Counterweight
The float switch can be installed with a counterweight to set the required switching range. By adjusting the cable length between the float and the fixed point, users can control the distance between ON and OFF levels.
Technical Specifications
| Item | THV-3 Round Flat Float Switch |
| Product Type | Cable Float Switch / Float Level Switch |
| Model | THV-3 |
| Body Shape | Round Flat Type |
| Function | Liquid Level Control / Pump Control |
| Contact Output | ON/OFF Switching Signal |
| Voltage Options | AC 110V / 220V |
| Max Current | 10A / 16A |
| Frequency | 50/60Hz |
| Protection Class | IP68 |
| Max Water Temperature | 60℃ |
| Cable Length | 1m, 2m, 3m, 4m, 5m, 10m, 15m, 20m or customized |
| Cable Options | H05RN-F 3×0.75mm², 3×1.0mm², 3×1.5mm² |
| Installation Accessory | Counterweight available on request |
| Typical Applications | Water tanks, pumps, sewage pits, drainage systems, industrial equipment |
Specifications can be adjusted according to the final product datasheet or customer project requirements.
How the THV-3 Float Switch Works
The THV-3 float switch moves with the liquid surface. When the water level reaches the set position, the float tilts and changes the contact state inside the switch. The control system then receives an ON or OFF signal.
For a drainage system, the switch can turn the pump on when the liquid level rises and stop the pump when the level drops. For a filling system, it can stop water intake when the tank is full or trigger a low-level alarm when the liquid drops too far.
This mechanical switching method is simple, stable and easy to maintain. It does not require complicated programming, making it suitable for both standard pump systems and OEM equipment.
Main Applications
Water Tank Level Control
The THV-3 can be used in clean water tanks, storage tanks and supply systems to maintain a safe liquid level and reduce manual monitoring.
Pump Start and Stop Control
It helps pumps work automatically according to the real liquid level, reducing the risk of dry running or overflow.
Sump and Drainage Systems
The round flat design is suitable for drainage pits, basement sump systems and small pump stations where space may be limited.
Sewage and Wastewater Control
For light wastewater and sewage pump applications, the THV-3 provides a simple level switching solution for pump control or alarm systems.
Industrial Equipment
The switch can be integrated into machines, washing equipment, cooling systems and other devices that require basic liquid level detection.
OEM Control Systems
With flexible cable length and practical structure, the THV-3 is suitable for manufacturers who need a compact float switch for customized equipment.
THV-3 vs. THV-1 and THV-2
The THV-3 is not just another shape in the same product family. Its round flat design gives it a different application focus.
| Model | Shape | Better For |
| THV-1 Triangular Float Switch | Triangular body | General pump control and wider movement space |
| THV-2 Rectangular Flat Float Switch | Rectangular flat body | Stable positioning and flat-side installation needs |
| THV-3 Round Flat Float Switch | Round flat body | Compact tanks, smooth movement, OEM-friendly appearance |
If the tank space is narrow or the customer prefers a cleaner round float design, the THV-3 is a better option. If the project requires a more traditional float shape, THV-1 or THV-2 may be selected depending on the installation environment.
Installation Notes
Install the float switch in an area where the float can move freely.
Avoid placing the float too close to the pump inlet, tank wall or moving parts.
Use a counterweight when a fixed switching range is required.
Do not immerse cable joints in water.
Make sure the voltage, current and wiring method match the control system.
For sewage or wastewater applications, check whether the liquid contains heavy solids, fibers or chemicals before selecting the final model.
Ordering Information
When sending an inquiry, please confirm the following details:
Required quantity
Cable length
Voltage and current requirement
NO/NC control function
Application: water tank, pump, sewage, drainage or OEM equipment
Liquid type and working temperature
Whether a counterweight is required
Packaging or branding requirements
This helps us recommend the correct configuration and avoid installation problems.
FAQ
What is the THV-3 Round Flat Float Switch used for?
It is used for liquid level control in water tanks, pump systems, drainage pits, sewage systems and industrial equipment. It can send an ON/OFF signal when the liquid reaches a set level.
Can the THV-3 control a water pump automatically?
Yes. The THV-3 can be connected to a pump control circuit to start or stop the pump according to the liquid level.
Is the cable length customizable?
Yes. Common cable lengths include 1m, 2m, 3m, 5m, 10m, 15m and 20m. Custom cable lengths are available for project orders.
Can it be used for sewage water?
It can be used in many drainage and light sewage applications. For liquids with heavy solids, fibers, oil or chemicals, please confirm the working environment before selecting the model.
What is the difference between THV-3 and THV-2?
THV-2 has a rectangular flat body, while THV-3 uses a round flat body. THV-3 is more suitable when the customer wants a compact round float switch with smooth movement and a cleaner OEM appearance.
Does the THV-3 need calibration?
No complicated calibration is required. The switching range is mainly adjusted by installation position and cable length between the float and fixed point.
Looking for a compact float switch for pump or tank level control?
Send us your cable length, voltage, liquid type and application details. Our team will help you choose the right THV-3 Round Flat Float Switch configuration for your project.
