910028NT Scald Protection Valve
The Legom 910028NT Scald Protection Valve is a self-acting thermostatic safety valve designed to prevent scalding by automatically shutting off water flow when outlet temperature exceeds the safe limit. When water temperature rises to the protection threshold, the internal thermostatic element closes the valve — completely stopping water flow through the outlet — and reopens automatically once temperature drops below the safe level. The valve requires no electricity, no manual intervention, and no external control signal to perform its safety function.
With a full close temperature of 35°C, an initial open of 36.7°C, and full open at 43.3°C, the 910028NT is designed for installations where the downstream water temperature must not exceed a defined safe limit — protecting users from accidental scalding in sanitary, solar water heating, and domestic hot water applications. Available in 3/8 NPT and 3/4 NPT thread specifications, with a maximum flow of 20 L/min at 300 kPa, maximum pressure of 1 MPa, and control accuracy of ±1°C.
Key Benefits
- Automatic scald protection — no electricity required – The thermostatic element responds purely to water temperature, closing the valve without any electrical connection, actuator, control signal, or user action when the outlet temperature exceeds the safe limit
- Full close at 35°C with ±1°C accuracy – Precise temperature control ensures the valve closes reliably at the defined protection threshold, providing consistent safety performance across the valve’s service life
- Automatic self-reset when temperature drops – Once water temperature falls below the protection threshold, the valve reopens automatically — no manual reset, no tool, and no service call required to restore normal operation
- Wide working temperature range of -30°C to 80°C – Suitable for installation in cold climate environments where ambient temperatures may drop below zero, as well as in hot water systems up to 80°C
- NPT thread specification – Available in 3/8 NPT and 3/4 NPT — the only Legom valve with NPT (National Pipe Thread) connections, providing direct compatibility with North American and international NPT plumbing systems
- High flow capacity at 20 L/min – Delivers up to 20 L/min at 300 kPa, supporting standard domestic hot water flow demands without restricting normal operation below the protection threshold
- 1 MPa maximum pressure rating – Suitable for standard domestic and commercial water supply pressures
- Brass construction – Durable and corrosion-resistant for long-term service in potable hot water systems
Technical Specifications
| Parameter | Specification |
|---|---|
| Model | 910028NT |
| Material | Brass |
| Full Close Temperature | 35°C |
| Initial Open Temperature | 36.7°C |
| Full Open Temperature | 43.3°C |
| Working Temperature | -30°C to 80°C |
| Max Pressure | 1 MPa |
| Max Flow | 20 L/min (at 300 kPa) |
| Control Accuracy | ± 1°C |
| Thread Specification | 3/8 NPT / 3/4 NPT |
| Dimensions | 95.5 ± 0.5mm (H); 3/8″-18NPT top, 3/4″-14NPT bottom |
Temperature Response Summary
| Water Temperature | Valve State | Water Flow |
|---|---|---|
| Below 35°C | Fully closed | No flow through valve |
| 36.7°C | Beginning to open | Flow commencing |
| 35°C – 43.3°C | Progressively opening | Increasing with temperature |
| 43.3°C and above | Fully open | Maximum flow |
Note: The valve is designed for scald protection by limiting flow below 35°C. When used in the intended application — as an outlet safety valve downstream of a hot water source — the thermostatic element senses the actual outlet water temperature and closes if it falls below the safe delivery threshold, preventing delivery of inadequately heated water that could harbor Legionella. Refer to the datasheet flowing curve for pressure drop vs flow rate data.
Application & Use Cases
- Solar water heating system outlet protection – Solar storage tanks can reach very high temperatures (60–80°C) during peak solar gain. Installing the 910028NT at the solar system outlet provides automatic temperature-based flow shutoff when delivered water temperature drops below the safe comfort threshold, preventing delivery of insufficiently heated water
- Electric storage water heater outlets – Applied as a safety valve on the outlet of electric water heaters where temperature control accuracy of the heater element may vary, providing a fail-safe temperature cutoff at the point of use
- Sanitary hot water safety in vulnerable user environments – Installed at shower, bath, or basin outlets in care homes, hospitals, schools, and facilities serving vulnerable users who may not be able to react quickly to unexpectedly hot water
- Heating and cooling system safety connections – Applied at terminal connections in hydronic heating systems where the delivered water temperature must be confirmed to be within a defined range before delivery to the user-side plumbing
- NPT plumbing systems in North American and international installations – The 3/8 NPT and 3/4 NPT thread options provide direct compatibility with North American plumbing standards, making the 910028NT appropriate for projects in markets where NPT threading is the standard
Installation Notes
- Install with the 3/8 NPT end upstream (water inlet) and the 3/4 NPT end downstream (water outlet), as shown in the dimension drawing. Incorrect orientation will prevent correct thermostatic operation
- Ensure the valve body is in direct contact with the flowing water whose temperature it is intended to sense. The thermostatic element inside the valve body must be fully wetted by the water stream for accurate temperature response
- Use appropriate NPT thread sealant (PTFE tape or pipe dope rated for hot water service) on both thread connections. Do not overtighten — brass NPT threads can be damaged by excessive torque
- Do not install downstream of a mixing valve where the water temperature has already been reduced to the user delivery temperature. The 910028NT should sense the hot water source temperature, not the mixed water temperature
- After installation, verify correct operation by running hot water through the valve and confirming flow stops when source temperature drops below 35°C (for example, as the water heater depletes) and resumes when temperature recovers
- The valve requires no maintenance under normal service conditions. If flow does not resume after a temperature recovery event, inspect the thermostatic element for debris or damage
Frequently Asked Questions
How does the 910028NT differ from a thermostatic mixing valve (TMV)?
A thermostatic mixing valve blends hot and cold water to deliver a fixed mixed temperature — for example, 38°C shower water from a 65°C hot supply and cold water. The 910028NT does not mix water. It is a single-inlet shutoff valve that allows or blocks flow based purely on whether the inlet water temperature is above or below the threshold. When the inlet water is above 36.7°C, the valve opens and water flows. When it drops below 35°C, the valve closes and flow stops completely. It is a temperature-actuated on/off valve, not a mixing valve.
Why does the valve close below 35°C rather than above a high temperature?
The 910028NT is designed for applications where water must be delivered at an adequate hot temperature — for example, at the outlet of a solar water heater or electric storage tank. When the water temperature drops below 35°C, it indicates that the hot water supply has been depleted or the heater is not producing adequate temperature. In this state, the valve closes to prevent delivery of lukewarm water that feels inadequate to the user or that may not meet hygiene temperature requirements for Legionella control. It is a minimum temperature guard, not a maximum temperature shutoff.
Does the valve require any maintenance or manual reset after closing?
No. The 910028NT is self-resetting — when water temperature rises above 36.7°C again, the thermostatic element expands and the valve reopens automatically. No manual reset, no tool, and no external intervention is required. Normal operation resumes as soon as the water supply temperature recovers above the opening threshold.
Why are the connections NPT rather than G thread?
NPT (National Pipe Taper Thread) is the standard pipe thread specification in North America and is also widely used in international markets outside Europe. The 910028NT’s NPT connections make it directly compatible with plumbing installations in North American markets and with equipment manufactured to NPT standards globally, where the G thread (parallel pipe thread) connections on other Legom valves would require adapters.
Can the 910028NT be customized for different temperature thresholds?
Yes. Legom offers OEM and ODM customization including water temperature range, open and close temperature thresholds, pressure rating, connection size, and body material. Contact the Legom team with your specific temperature requirements and system parameters to discuss customization options.
OEM & ODM Customization
Legom supports full OEM and ODM services for the 910028NT Scald Protection Valve. Customization parameters include water temperature range, open and close temperature thresholds, pressure rating, connection size, and body material. 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.
