910033NT Water Return System Control Valve

• Eliminates wait time for hot water at remote fixtures – The primary function. In homes or buildings where the water heater is far from a bathroom or kitchen, the 910033NT enables near-instant hot water delivery by continuously or on-demand recirculating cooled pipe water back to the heater — no wasted cold water purge required
• Opens at 30–33°C, closes at 35–37°C – Temperature-actuated operation with a narrow 5–7°C differential between open and close temperatures ensures the valve responds decisively to the arrival of hot water, preventing premature closure on warm water and preventing the valve from staying open once hot water is present
• Prevents water waste – Without a return system control valve, users must run the tap until hot water arrives, wasting the entire volume of cold water standing in the pipe. The 910033NT recirculates this water back to the heater rather than letting it drain
• Energy-efficient operation – By returning cooled pipe water to the heater for reheating rather than purging it to drain, the thermal energy stored in the standing water is recovered, reducing the energy required to reheat the water heater
• Compatible with solar and electric water heating systems – The 55–75°C mixing water temperature range covers the output temperature of both solar thermal collectors and electric storage water heaters
• Self-acting thermostatic operation – No electrical connection, actuator, or control signal required for the valve itself. It responds purely to water temperature — opening and closing automatically based on the thermal state of the water in the pipe
• Brass construction with 10 Bar proof pressure – Durable brass body rated for standard domestic and commercial water supply pressures
• OEM and ODM customization available – Temperature range, pressure rating, and connection size can be customized

The 910033NT is the thermostatic heart of an H-type intelligent hot water return system. The complete system consists of the water heater, a temperature control box with a water flow induction switch, a circulation pump, the hot water distribution pipe, the cold water supply pipe, and the 910033NT valve installed at the furthest fixture connection point.

When the user wants hot water: They open the tap briefly for 2–6 seconds then close it. The water flow induction switch senses this flow event, signals the temperature control box, which starts the circulation pump.

While pipe water is cold (below 33°C): The 910033NT is open. The circulating pump draws the stagnant low-temperature water from the hot water pipe back through the valve and into the cold water pipe, returning it to the water heater for reheating. Simultaneously, fresh hot water from the heater flows into the hot water pipe toward the fixture.

When hot water reaches the valve (above 35°C): The thermostatic element in the 910033NT detects the temperature rise and closes the valve. Hot water now flows directly through the hot water pipe to all fixtures on the distribution loop. The circulation pump stops.

Result: The user opens the tap and receives hot water almost immediately — with no wasted cold water purged to drain and no energy wasted reheating from cold.

• Residential homes with remote bathrooms or kitchens – The most common application. In homes where the water heater is centrally located and the master bathroom or kitchen is at the far end of the building, the 910033NT enables near-instant hot water delivery to the furthest fixture without wasting water or waiting
• Solar thermal water heating systems – Solar storage tanks often operate at 55–75°C, matching the valve’s mixing water temperature range. The 910033NT ensures efficient distribution of solar-heated water to remote fixtures without the long purge wait typical of solar systems with extended pipe runs
• Electric storage water heaters – Applied in buildings with electric hot water storage where long pipe runs between the storage tank and remote outlets waste significant water and energy during the daily purge cycle
• Multi-bathroom residential buildings – Installed at the furthest bathroom in the hot water distribution loop, serving all intermediate bathrooms and the kitchen simultaneously through the recirculation system
• Commercial sanitary installations – Applied in hotels, apartment buildings, and commercial facilities where immediate hot water delivery at all outlets is a service standard and water waste is a sustainability concern

• Install the 910033NT at the furthest fixture connection point from the water heater in the hot water distribution loop — typically the remote bathroom or kitchen. The H-type valve connects the hot water pipe (H) to the cold water pipe (C) at this point
• The four G1/2 connections on the valve body connect to: hot water pipe inlet (H), cold water return pipe outlet (C), and the fixture supply connections. Follow the installation diagram in the datasheet for correct pipe routing
• The complete H-type system requires: a temperature control box, a water flow induction switch at a fixture, and a circulation pump — in addition to the 910033NT valve. The 910033NT is the thermostatic control element of this system, not a standalone device
• Flush the pipework before installation to remove grit and debris that could damage the thermostatic element inside the valve
• Use appropriate thread sealant or PTFE tape on all four G1/2 connections
• After installation, test the system by briefly opening and closing the trigger tap and verifying that the circulation pump starts, hot water arrives at the trigger fixture within the expected time, and the pump stops when hot water reaches the valve

Legom supports full OEM and ODM services for the 910033NT Water Return System Control Valve. Customization parameters include mixing 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.