Watts
Watts 1/2 Thermostatic Mixing Valve Brass 20 gpm PEX 1/2 in
A thermostatic mixing valve delivers 20 gpm at 125 psi with 1/2 in PEX connections and a 80 to 120 °F range
- TypeDrain Components
- Thermostatic control delivers safe water temperatures from 80 to 120 Degrees F
- Brass body withstands up to 150 psi maximum pressure for lasting durability
- High 20 gpm flow rate at 125 psi supplies strong output for multiple fixtures
- PEX inlet and outlet connections simplify installation on 1/2 in tubing
- Handles hot inlet up to 180 Degrees F and cold inlet down to 39 Degrees F
Brass Thermostatic Mixing Valve
The Watts 1/2 LF MMV-PEX is a thermostatic mixing valve built for residential plumbing systems. It blends hot and cold water to a safe, consistent temperature for baths, lavatories, showers and sinks. The brass body provides durability in continuous service. Installers working with PEX tubing will appreciate the direct PEX inlet and outlet connections.
Thermal Performance and Pressure
Cold water enters between 39 and 85 degrees F while hot water enters between 120 and 180 degrees F. The valve delivers a mixed outlet range of 80 to 120 degrees F. It flows 20 gpm at 125 psi and withstands a maximum pressure of 150 psi. These ratings suit typical domestic supply conditions without excessive pressure drop.
Half-Inch PEX Connection Sizing
Both inlet and outlet ports are sized at 1/2 in for PEX tubing. This single specification decides whether the valve fits your existing rough-in or requires adapters. The overall height is 5 9/16 in and width is 5 1/4 in, so verify cavity space before purchase. Builders needing larger port diameters or copper sweat connections must select a different model.
Highlights
- Thermostatic control delivers safe water temperatures from 80 to 120 Degrees F
- Brass body withstands up to 150 psi maximum pressure for lasting durability
- High 20 gpm flow rate at 125 psi supplies strong output for multiple fixtures
- PEX inlet and outlet connections simplify installation on 1/2 in tubing
- Handles hot inlet up to 180 Degrees F and cold inlet down to 39 Degrees F
Specifications
| Type | Drain Components |
|---|---|
| Brand | Watts |
| Model | 1/2 LF MMV-PEX |
Questions about this item
How do I install the Watts 1/2 LF MMV-PEX mixing valve and what step is commonly missed?
Connect the 1/2 in PEX inlets for hot and cold water, ensuring hot supply is 120 to 180 Degrees F and cold is 39 to 85 Degrees F. The step often missed is verifying inlet temperatures fall within these ranges before finalizing connections.
What maintenance or replacement will the Watts 1/2 LF MMV-PEX mixing valve need over time?
The brass valve body resists corrosion, but internal thermostatic elements can wear. Plan to inspect or replace the cartridge if output temperature drifts outside the 80 to 120 Degrees F range or flow drops below 20 gpm at 125 psi.
What is the first performance limit reached on the Watts 1/2 LF MMV-PEX under sustained high-demand use?
The valve is rated for 20 gpm at 125 psi with a maximum pressure of 150 psi. Under sustained demand, the 20 gpm flow capacity or the 150 psi pressure ceiling will be the limiting factor, whichever is reached first.
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