DN40 Thermostatic Valve HFT65002
The Legom HFT65002 DN40 Thermostatic Valve is a commercial thermostatic mixing valve featuring G1½ union connections for straightforward installation and removal without rotating the valve body in the pipework. Delivering the same thermostatic mixing performance as the wider HFT series — temperature adjustment range 20–60°C, control accuracy ±2°C, working pressure range 0.03–1 MPa — the HFT65002 adds the practical advantage of union fittings that allow the valve to be disconnected and serviced in minutes without disturbing surrounding pipework.
Manufactured from 57-3 copper with nickel plating with a silk-screen ABS black handwheel, the HFT65002 suits commercial water heater installations, solar thermal systems, and any application where ease of future maintenance is a design priority. Hot water inlet range of 30–99°C and cold water inlet range of 5–29°C cover all standard commercial and domestic water heater types. Factory-preset temperature ranges are available for OEM and project orders requiring restricted operator adjustment.
Key Benefits
- Union connections for fast installation and servicing – G1½ union fittings allow the valve body to be connected and disconnected without rotating it in the pipework, significantly reducing installation time and enabling cartridge replacement or valve swap-out without cutting or re-threading pipes
- DN40 flow capacity for commercial applications – Sized for commercial systems with moderate-to-high hot water demand, providing higher flow capacity than the DN20 domestic HFT30001 while remaining more compact than the DN50 HFT70002
- Temperature control accuracy of ±2°C – Consistent mixed water delivery within ±2°C of the set point across varying supply conditions, providing reliable safety and comfort performance in commercial hot water distribution
- 20–60°C adjustment range – Full-range handwheel adjustment for commissioning flexibility, with factory-preset narrower ranges available for safety-restricted applications
- No electricity required – Self-acting thermostatic operation requiring no electrical connection, controls, or power supply at the valve location
- 57-3 copper body with nickel plating – Durable, corrosion-resistant construction for long-term service in continuous commercial hot water environments
- Wide pressure range of 0.03–1 MPa – Suitable from gravity-fed low-pressure systems through standard mains-pressure commercial water supply
- Compatible with all commercial water heater types – 30–99°C hot inlet range covers electric, gas, solar thermal, and heat pump commercial systems
Technical Specifications
| Parameter | Specification |
|---|---|
| Model | HFT65002 |
| Body Material | 57-3 copper, nickel plated |
| Handwheel | ABS black silk-screen, 40mm |
| Connection | G1½ union (DN40) |
| Temperature Adjustment Range | 20–60°C (standard); 35–55°C / 40–50°C / 30–60°C (preset options) |
| Temperature Control Accuracy | ± 2°C |
| Working Pressure Range | 0.03 MPa – 1 MPa |
| Ideal Working Pressure | 0.1 MPa – 0.5 MPa |
| Cold Water Temperature Range | 5°C – 29°C |
| Hot Water Temperature Range | 30°C – 99°C |
| Primary Use | Commercial water heater systems |
HFT Series — Connection Type Comparison
| Model | Connection Type | Size | Removal for Service |
|---|---|---|---|
| HFT30001 | Internal thread | G1/2 / G3/4 | Requires unscrewing valve body |
| HFT70001 | Internal thread | G2 / DN40 | Requires unscrewing valve body |
| HFT70002 | Internal thread | G2 / DN50 | Requires unscrewing valve body |
| HFT65002 | Union | G1½ / DN40 | Union nuts — no valve body rotation needed |
Application & Use Cases
- Commercial installations requiring easy future maintenance access – The union connection design is particularly valuable in plant rooms, ceiling voids, and confined spaces where rotating a large valve body for removal is impractical — union nuts allow the valve to be disconnected with a spanner in minutes
- Commercial solar thermal hot water systems – Solar storage systems regularly require valve cartridge inspection due to the high temperatures involved. Union connections allow cartridge service without disrupting the surrounding pipework
- Hotels, schools, and care facilities – Mid-size commercial buildings where DN40 flow capacity matches hot water demand and where the building manager expects periodic maintenance access to be straightforward
- Retrofit and replacement installations – Where an existing TMV is being replaced and the surrounding pipework cannot be easily rotated, union connections enable the new valve to be fitted and removed without modifying the pipe connections
- Systems with frequent cartridge replacement requirements – In hard water areas or high-usage facilities where cartridge replacement is expected annually, union connections significantly reduce the plumber’s time on site for each service visit
Installation Notes
- Install the union tail pieces onto the hot (H), cold (C), and mixed (M) pipe ends first, using appropriate thread sealant. Once the tail pieces are installed and sealed, the valve body can be connected and disconnected by tightening or loosening the union nuts — no rotation of the valve body is required
- Ensure union sealing washers or O-rings are correctly seated before tightening union nuts. Do not overtighten — hand-tight plus a quarter turn is sufficient for a leak-free union joint in most configurations
- Install isolation valves on both hot and cold supply lines upstream of the HFT65002 to allow valve disconnection without draining the system
- Install a strainer on the cold inlet to protect the thermostatic cartridge from debris
- After installation, verify mixed water outlet temperature at the furthest fixture with a calibrated thermometer before commissioning for occupant use
- The valve performs optimally at 0.1–0.5 MPa — verify inlet pressure is within this range at peak flow
Frequently Asked Questions
What is a union connection and why is it better for servicing?
A union is a three-part pipe fitting — two end connectors (tail pieces) that are permanently soldered or threaded onto the pipe ends, and a central union nut that draws them together and seals the joint. To disconnect, you simply loosen the union nut. The valve body can then be lifted out without rotating it or disturbing the surrounding pipes. This is particularly valuable for TMVs because thermostatic cartridges require periodic inspection and replacement — with standard threaded connections, removing the valve requires rotating a heavy valve body in potentially confined pipe spaces, often disturbing seals in the process. Union connections eliminate this entirely.
How does the HFT65002 compare to the HFT70001 in terms of performance?
Both valves provide the same thermostatic mixing performance — identical temperature range (20–60°C), accuracy (±2°C), pressure range (0.03–1 MPa), and fluid compatibility. The only difference is the connection type: the HFT65002 uses union fittings (G1½) while the HFT70001 uses internal thread (G2). Choose the HFT65002 when serviceability and ease of future maintenance are priorities. Choose the HFT70001 when the existing pipework already has male threaded connections that match the valve’s internal thread.
Can the temperature range be restricted for safety?
Yes. Factory-preset ranges of 35–55°C, 40–50°C, or 30–60°C are available on OEM and project orders, mechanically limiting handwheel travel to prevent users from setting the outlet above the preset maximum. Contact the Legom team to specify the required preset range when ordering.
OEM & ODM Customization
Legom supports OEM and ODM services for the HFT65002 DN40 Thermostatic Valve. Customization options include preset temperature range, connection size, body finish, and handwheel design. Contact us via WhatsApp or info@legomsmart.com.
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.
