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Moen's New Thermostatic Mixing Valves

At a Glance: The New Thermostatic Mixing Valves
Help plumbers meet code requirements while offering improved health, safety and comfort

Moen now offers two thermostatic mixing valves (TMV).


Photo Credit: Moen Incorporated
Low Flow TMV (104451)
  • Faucet Application
  • Factory preset at 105 ░ F
  • Adjustable from 95 ░ F (35 ░ C) to 115 ░ F (46 ░ C), with a ▒ 3.5 ░ F (▒ 2 ░ C) temperature accuracy
  • Flow rate @ 45 PSI = 3.7 gpm

Photo Credit: Moen Incorporated
High Flow TMV (104465)
  • Tub Application
  • Factory preset at 115 ░ F - 120 ░ F
  • Adjustable from 95 ░ F (35 ░ C) to 115 ░ F (46 ░ C), with a ▒ 3.5 ░ F (▒ 2 ░ C) temperature accuracy
  • Flow rate @ 45 PSI = 10 gpm

How it Works
The valve uses a paraffin-based thermostatic engine to maintain a relatively constant outlet temperature. If water in the valve gets hotter than the set point, the paraffin quickly expands, moving the valve seat to let more cold water in. If the water temperature drops below the set point, the wax contracts, causing the valve to let more hot water into the mix. The valve shuts down completely if there's an interruption in the hot or cold water supply.

Moen's TMV is easy to use and flexible. Its features include:

  • Adjustable temperature control.
  • A temperature accuracy of ▒ 3.5 ░ F.
  • A compact design made to squeeze into tight spaces.
  • Stainless steel strainers to protect against line trash.
  • A vandal-resistant cover that protects the valve from damage.

TMVs are required by many regional plumbing codes, serving two important purposes: They help prevent bacteria growth while protecting users against scalding. Here's how they work: Hot water in a storage tank must be kept at temperatures above 140 degrees Fahrenheit to kill Legionella bacteria, but water at that temperature is dangerous. It can cause third-degree burns in adults after a five-second exposure and in children after just one second. Because of this danger, that same water should be no hotter than 120 degrees F when it reaches the tap.

The TMV mixes hot water with cold water to lower its temperature below the 120 F threshold. This allows the customer to set their water heater at a high enough temperature to kill bacteria while eliminating concerns about water being too hot at the faucet or tub. Mixing hot and cold water also increases the volume of available hot water.

Moen's new valves come in both high- and low-flow versions to provide safe water temperature for different applications. The high-flow TMV (10gpm at 45psi) is for Roman tubs or tub systems; the low-flow TMV (3.7gpm at 45psi) is appropriate for a single lavatory faucet or a bank of up to eight lavatory faucets providing extra safety to commercial lavatories.