910078NT ANTI-FREEZE VALVE
The 910078NT Anti-Freeze Valve is a self-acting freeze protection valve designed for closed circulation systems in heat pump installations. When water temperature inside the pipe drops below 3°C, the valve automatically opens to drain circulating water, preventing freeze damage to pipes and valves during unexpected power outages or system failures. When temperature rises above 4°C, the drainage piston automatically closes.
Manufactured from EN12165 CW617N / C46500 brass alloy, this valve operates entirely without external power or manual intervention – making it a reliable, low-maintenance solution for heat pump and HVAC systems in cold climates. Available in three connection sizes: G 1″ (DN25), G 1¼” (DN32), and G 1½” (DN40).
Key Benefits
- Fully automatic freeze protection – Opens at 3°C and closes at 4°C with ±1°C control accuracy, requiring zero manual operation
- No external power required – Self-acting thermostatic piston mechanism eliminates electrical dependency and reduces failure risk
- Wide ambient temperature tolerance – Rated for ambient conditions from -30°C to 60°C, suitable for extreme cold environments
- High-quality brass alloy body – EN12165 CW617N / C46500 construction ensures long-term corrosion resistance and pressure integrity
- Three connection sizes available – G 1″ (DN25), G 1¼” (DN32), and G 1½” (DN40) to suit different pipe configurations
- Recommended for both flow and return pipes – Install on both pipes for complete outdoor pipe freeze protection
- OEM & ODM customization available – Opening temperature, connection size, and body material can be customized for specific project requirements
Technical Specifications
| Parameter | Specification |
|---|---|
| Model | 910078NT |
| Valve Body Material | EN12165 CW617N / C46500 Brass Alloy |
| Medium | Water |
| Maximum Working Pressure | 10 bar |
| Working Temperature Range | 0°C to 65°C |
| Ambient Temperature Range | -30°C to 60°C |
| Opening Temperature | 3°C |
| Closing Temperature | 4°C |
| Control Accuracy | ±1°C |
| Test Pressure (before) | 3 bar |
| Pressure Difference (after test) | 1 bar |
KV & Flow Rate
| Connection | DN | KV (m³/h) | Q3 (l/h) | Q0.5 (l/h) |
|---|---|---|---|---|
| G 1″ | 25 | 55 | 0.3 | 3 |
| G 1¼” | 32 | 70 | 0.3 | 3 |
| G 1½” | 40 | 88 | 0.3 | 3 |
KV: Flow rate at 1 bar pressure loss (m³/h) | Q3: Flow rate at 3°C water temp & 3 bar pipeline pressure (l/h) | Q0.5: Flow rate at 0.5°C water temp & 3 bar pipeline pressure (l/h)
Dimensions (mm)
| DN | A (G) | L | L1 | L2 | H1 | H2 |
|---|---|---|---|---|---|---|
| 25 | 1″ | 52 | 10 | 10 | 82.5 | 32.5 |
| 32 | 1¼” | 59 | 14 | 14 | 84.5 | 34 |
| 40 | 1½” | 62 | 15.5 | 15.5 | 86 | 35.5 |
Application & Use Cases
- Heat pump systems – Installed on outdoor pipes connecting heat pump to indoor unit, the most freeze-prone section during power failure or system malfunction
- Closed circulation HVAC systems – Protects circulating water from freezing during unexpected shutdowns
- Underfloor heating systems – Cold-climate installations where pipes may be exposed to freezing during shutdown periods
- Solar thermal systems – Collector circuits exposed to freezing temperatures overnight or in winter
- Vacation homes and seasonal buildings – Where heating systems are not continuously operated
Installation Notes
- Install the valve vertically with the outlet facing downwards to allow drained water to flow out smoothly and free from obstructions
- Install on the outdoor pipes connecting the heat pump to indoor unit – these are the sections most vulnerable to freezing during power failure or system malfunction
- It is recommended to install on both flow and return pipes to fully protect outdoor piping from freezing
- Keep the valve away from heat sources to ensure correct thermostatic function
- The valve body must not be insulated – it must be exposed to ambient air temperature to respond accurately
- The outlet must be at least 15 cm above ground level to prevent ice accumulation from blocking the outlet
- If installing two valves (flow and return), maintain a minimum distance of 10 cm between them
- Avoid trap connections in the pipe – trap shapes can lead to water accumulation and compromise frost protection
- When installed outdoors, use a protective cover over the valve to shield it from rain, snow, and direct sunlight
- The system must maintain pressure at all times to ensure proper functioning of the anti-freeze valve
- No electrical connection or controller required
Frequently Asked Questions
How does the 910078NT Anti-Freeze Valve work?
When water temperature inside the valve drops below 3°C, the temperature-sensitive element automatically opens the piston for drainage. When temperature exceeds 4°C, the drainage piston automatically closes, stopping the drainage. The system must maintain pressure at all times for the valve to function correctly.
Does this valve require electricity to operate?
No. The 910078NT is entirely self-acting with no need for power supply, wiring, or external controllers – making it reliable even during power outages.
Where exactly should this valve be installed in a heat pump system?
Install on the outdoor pipes connecting the heat pump to the indoor unit – these are the sections most vulnerable to freezing during power failure or system malfunction. Install on both flow and return pipes. The valve must be installed vertically with the outlet facing downward, at least 15 cm above ground level.
Which connection size should I choose?
The 910078NT is available in G 1″ (DN25), G 1¼” (DN32), and G 1½” (DN40). Select the size that matches the pipe connection at the installation point on your heat pump system.
Can the valve be insulated?
No. The valve body must remain free of insulation at all times. It needs direct exposure to ambient air temperature to activate correctly when freezing conditions occur.
Can the opening temperature be customized?
Yes. Legom offers OEM and ODM customization including opening temperature, connection size, and valve body material. Contact our team to discuss your specifications.
OEM & ODM Customization
Legom supports full OEM and ODM services for the 910078NT Anti-Freeze Valve. Our engineering team can customize opening and closing temperature thresholds, connection sizes, and body materials to match your product requirements. All customization projects are handled with strict confidentiality. Contact us via WhatsApp or info@legomsmart.com.
Datasheet
Product information last reviewed by the Legom Technical Team. For the most current specifications, refer to the official datasheet or contact our sales team.
Custom OEM & ODM Solutions
Legom is a direct manufacturer offering end-to-end OEM and ODM services. With our in-house engineering and production capabilities, we work closely with distributors and system integrators to deliver fully customized solutions under strict NDA.
