Watts 204158 Thermostatic Mixing Valve 3/8 Inch

Product Description

The WATTS 204158 is a lead-free, under-sink thermostatic mixing valve designed to deliver consistent, scald-protected water temperatures at the point of use. Built from brass with compression connections, the valve blends hot and cold supply lines to maintain a stable output temperature between 80 and 120 degrees F. Internal dual check valves block reverse flow between the hot and cold inlets, and integrated strainers intercept particulate before it reaches the cartridge. All functional internals are housed in a removable, serviceable cartridge, which simplifies long-term maintenance. The Cross Sense feature uses temperature-sensitive visual indicators to flag any cross-connection condition at the inlets, giving the installer or service tech an immediate read on system integrity.

The 204158 is sized at 3/8 inch with compression joint connections and is rated for supply pressures between 30 and 150 psi. It is intended for point-of-use installation beneath sinks or counters in facilities where scald prevention is a priority. Typical deployment sites include hospitals, elder care homes, schools, and commercial restrooms where consistent fixture-level temperature control is required by code or facility policy. A licensed plumber handles installation in most jurisdictions, and the valve is compliant with lead-free standards applicable to potable water systems.

Key Features

• Maintains output temperature between 80 and 120 degrees F to reduce scald risk at the fixture
• Cross Sense visual indicator identifies inlet cross-connection conditions at a glance
• Dual internal check valves prevent backflow between hot and cold supply lines
• Integrated inlet strainers protect the cartridge from particulate contamination
• Removable, serviceable cartridge supports long-term maintenance without full valve replacement
• Lead-free brass construction meets potable water requirements

Compatibility

Designed for point-of-use installation on 3/8 inch compression supply lines beneath sinks or counters in residential, commercial, and institutional plumbing systems where thermostatic scald protection is required.

Installation Notes

Installation is performed by a licensed plumber. Shut off the hot and cold supply stops and relieve line pressure before making any connections. Compression fittings require proper tube preparation and ferrule seating — do not overtighten. Verify inlet identification and check the Cross Sense indicator after startup to confirm no cross-connection is present before returning the fixture to service.

Technical Specifications

• Material: Brass
• Finish: Brass
• Connection Method: Compression
• Connection Type: Compression Joint
• Size: 3/8 inches
• Temperature Range: 80 degrees F - 120 degrees F
• Minimum Pressure: 30 psi
• Maximum Pressure: 150 psi
• Lead Free: Yes
• Application: Point of Use

Standard Information

• Brand: WATTS
• Manufacturer Part Number: 204158