910021NT Thermostatic Mixing Valve
The Legom 910021NT Thermostatic Mixing Valve is a high-flow thermostatic mixing valve designed for living water systems, underfloor heating, solar water heaters, and electric water heater installations. With a flow rate of 60 L/min, a KV of 3.0 m³/h, and four G3/4″ connections in a compact 96 × 108mm body, the 910021NT delivers significantly higher throughput than standard domestic TMVs — making it the appropriate choice for central whole-house mixing stations and solar thermal distribution systems where multiple outlets must be served simultaneously from a single mixing point.
The valve adjusts mixed outlet temperature across a range of 30–65°C with a temperature stability of ±2°C, using a wax thermostatic cartridge that responds to the actual mixed water temperature at the outlet. Maximum static pressure is 16 bar and maximum working pressure is 5 bar, with a maximum hot inlet temperature of 90°C — covering the full output range of solar thermal collectors, electric storage water heaters, and gas-fired systems. The brass valve body with ABS orange adjustment cap is recognisable from its prominent “MIX” label on the body face.
Key Benefits
- 60 L/min flow rate — high capacity central mixing – With a KV of 3.0 m³/h and 60 L/min maximum flow, the 910021NT serves multiple simultaneous hot water outlets from a single central mixing station — bathrooms, kitchens, and underfloor heating circuits running concurrently without flow restriction
- Four G3/4″ connections – The four-port connection layout provides flexible pipework routing for central mixing station installation, accommodating hot supply, cold supply, mixed outlet, and bypass or additional circuit connections in a single valve body
- 30–65°C adjustable temperature range – The wide adjustment range covers both comfort hot water delivery (38–45°C for showers and baths) and higher-temperature applications including underfloor heating supply (45–55°C) and anti-scald protection at any set point within the range
- 16 bar static pressure, 5 bar working pressure – Rated for the high static pressures present in mains-connected systems and multi-storey buildings, with a 5 bar maximum working pressure covering all standard domestic and light commercial water supply conditions
- 90°C maximum hot inlet temperature – Compatible with the highest storage temperatures used in solar thermal systems, including the elevated temperatures during peak solar gain or stagnation, providing a wide temperature differential between hot supply and mixed outlet for effective mixing control
- ±2°C temperature stability – Consistent mixed water delivery within ±2°C of the set point across varying supply pressure and flow conditions, maintaining safe outlet temperature under simultaneous multi-outlet demand
- Brass body with ABS adjustment cap – Durable brass valve body for long-term potable water service with a high-visibility orange ABS adjustment cap for clear identification and easy temperature setting adjustment
- Simple structure — easy installation – Compact 96 × 108mm body with four standard G3/4″ threaded ports for straightforward inline installation in central plant room or airing cupboard locations
Technical Specifications
| Parameter | Specification |
|---|---|
| Model | 910021NT |
| Body Material | Brass + ABS |
| Connections | 4 × G3/4″ |
| Max Pressure (Static) | 16 bar |
| Max Working Pressure | 5 bar |
| Max Inlet Temperature | 90°C |
| Adjustable Temperature Range | 30°C – 65°C |
| KV | 3.0 m³/h |
| Flow Rate | 60 L/min |
| Temperature Stability | ± 2°C |
| Dimensions | 96mm (W) × 108mm (H); cap Ø45mm |
910021NT vs Standard HFT TMV — Capacity Comparison
| Parameter | 910021NT | HFT30001 G3/4 |
|---|---|---|
| Flow rate | 60 L/min | ~20 L/min typical |
| KV | 3.0 m³/h | ~0.8–1.2 m³/h typical |
| Connections | 4 × G3/4″ | 3 × G3/4″ |
| Max static pressure | 16 bar | 10 bar typical |
| Temp range | 30–65°C | 20–60°C |
| Best for | Central mixing station | Individual fixture |
Application & Use Cases
- Central whole-house hot water mixing station – Installed at the central hot water distribution point — airing cupboard, plant room, or boiler room — to serve all hot water outlets in the building simultaneously at a safe mixed temperature, with the 60 L/min capacity handling simultaneous demand from multiple bathrooms and kitchen outlets
- Solar thermal water heating systems – Solar storage tanks regularly reach 70–90°C during peak solar gain. The 910021NT’s 90°C maximum inlet temperature and 30–65°C adjustment range make it the appropriate central mixing valve for large solar thermal systems, blending hot solar-heated water with cold to deliver safe outlet temperatures throughout the building
- Underfloor heating supply temperature control – Applied at the underfloor heating manifold supply connection to blend high-temperature boiler or heat pump output with cooler return water, delivering the 35–55°C supply temperature required by underfloor heating systems from a single central mixing point
- Electric storage water heater central mixing – Installed downstream of large-capacity electric storage water heaters where storage temperatures are maintained above 60°C for Legionella control and the 910021NT blends down to safe delivery temperatures for the building’s distribution system
- Living water systems – Applied as the central temperature control point in residential fresh water systems where consistent, safe hot water delivery temperature must be maintained across multiple simultaneous draw-off points
Installation Notes
- Connect the hot water supply to the hot inlet port, cold water supply to the cold inlet port, and the mixed water distribution to the mixed outlet port. The fourth G3/4″ port can be used for a bypass, secondary circuit, or additional distribution connection as required by the system design
- Install isolation valves on both hot and cold supply inlets upstream of the 910021NT to enable valve servicing and cartridge inspection without shutting down the building hot water supply
- Install a strainer on the cold inlet upstream of the valve to protect the thermostatic cartridge from particulate debris in the supply water
- The orange ABS adjustment cap sets the mixed outlet temperature — rotate to adjust. Allow the system to stabilise for at least 2 minutes after each adjustment before measuring outlet temperature at the furthest fixture
- After installation, verify mixed water outlet temperature at the furthest fixture with a calibrated thermometer before commissioning for occupant use
- The 910021NT is designed for installation in a protected plant room or airing cupboard — not for outdoor installation or frost-exposed locations without additional insulation and protection
- Flush all supply pipework thoroughly before connecting to remove scale, grit, and installation debris that could damage the thermostatic cartridge
Frequently Asked Questions
How does the 910021NT differ from the HFT series TMVs?
The HFT series valves — from G1/2 to G2 — are designed for individual fixture, single water heater outlet, or light commercial applications with flow rates typically in the range of 10–30 L/min. The 910021NT is a central mixing station valve designed for whole-house or multi-circuit applications at 60 L/min — approximately three times the capacity of standard domestic TMVs. It also has four G3/4″ connection ports (versus the three ports on standard TMVs), a higher maximum static pressure of 16 bar, and a temperature adjustment range extending to 65°C to accommodate solar thermal and underfloor heating applications. Choose the 910021NT when serving multiple simultaneous outlets from a central mixing point. Choose HFT series valves for individual fixture or single water heater outlet applications.
Why does this valve have four connection ports?
Standard three-port TMVs have one hot inlet, one cold inlet, and one mixed outlet. The 910021NT’s fourth port provides additional connection flexibility for central mixing station applications — it can be used as a second mixed outlet serving a different distribution circuit, a bypass connection for pressure management, a secondary cold inlet, or a connection point for a recirculation return. The specific use of the fourth port depends on the system design. Refer to the installation diagram in the datasheet or contact the Legom team for guidance on four-port configuration for your specific application.
What is the maximum temperature this valve can handle at the hot inlet?
The 910021NT accepts hot inlet temperatures up to 90°C — the upper limit of standard solar thermal storage temperatures and electric water heater settings. This makes it suitable for direct connection to solar collectors, electric storage tanks set at maximum anti-Legionella temperatures (typically 60–65°C), and gas-fired systems. For applications where inlet temperature may exceed 90°C (such as certain industrial or high-temperature solar systems), contact the Legom team for alternative valve recommendations.
Can the 910021NT be used for underfloor heating supply temperature control?
Yes. The 30–65°C adjustment range covers the typical underfloor heating supply temperature requirement of 35–55°C, and the 60 L/min flow capacity handles the flow demands of standard residential underfloor heating manifold systems. The valve can be installed at the manifold supply connection to blend high-temperature boiler or heat pump output with cooler return water to achieve the required underfloor heating supply temperature. For larger commercial underfloor heating systems with higher flow requirements, contact the Legom team to confirm suitability.
OEM & ODM Customization
Legom supports OEM and ODM services for the 910021NT Thermostatic Mixing Valve. Customization options include temperature range, pressure rating, connection configuration, and body materials. 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.
