Haws TWBS.HF Thermostatic Mixing Valve

Model TWBS.HF, lead-free Emergency Valve (patent pending), thermostatically mixes hot and cold water to provide a safe, tepid water supply for emergency shower and eyewash equipment. The valve includes a secondary high-temperature limit valve for added protection in the event of main tempering valve malfunction. To ensure fail-safe operation, a pressure-sensing diverter valve opens the cold-water bypass if hot-water pressure is lost, the thermostat malfunctions, or the cold-water check-stop becomes clogged.

The valve delivers a flow rate of 1 to 78 GPM (3.8 to 295 L/min) for precise temperature control across the operating range, with the lowest internal pressure drop in its class—an advantage where supply pressure is limited. Cold-water bypass provides up to 79 GPM at 30 PSI (100% of rated capacity) in the event of hot-water supply failure.

Wax-based thermostat technology ensures fast response and reliable temperature control. Oversized valve seats resist failures caused by debris, while a new shuttle design eliminates sticking. A custom funnel improves temperature control at low flows. Modular low-lead brass construction with internal check stops provides durability and serviceability. Outlet temperature is factory set to 85°F (29°C) with an adjustable high-limit stop set to 90°F (32°C).

Compliance: Certified to ASSE 1071, NSF 61, California Health and Safety Code 116875 (AB 1953-2006), and applicable sections of CSA B125.3. Tested cold-water failure rate is 0.0 GPM in accordance with ASSE 1071.