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Thermostatic valve elements

Thermostatic valve elements are the parts that create the mechanical movement within a thermostatic temperature control valve. The valve elements regulate the opening and closing of the valve at a set temperature. A special wax is placed deep in the bottom ‘nut’ of an element. The expansion of the wax pushes the piston inside of the element and the push regulates the valve and controls the flow.

The sliding of the element piston will control where the flow is going based on what is happening with the temperature of the medium. The element is closed when the media is “cold” or below the nominal temperature. When the wax gets heated, it will expand and push the sliding valve out, which will cause the thermostatic valve to open or close according to the preset.

How does the element work inside of a three-way valve:

  • Crack open
    Element closed below Crack Open Temperature. All the flow is coming from the B port, bypass, and goes to the A port. Nothing is coming from the C port in a 3-way valve situation.
  • 50% open position
    Element is 50% open at Control Temperature. After the crack open temperature has been reached, the element will be open, maybe not all the way, and some flow is coming from B, some from C, and will get mixed going thru A.
  • Full open
    Element 100% open above Full Open Temperature. All the flow is coming from the C port, the cooler side, and the media is hotter than the nominal temperature. Once enough cold media has gone thru that the element cools down, the element will close.

The maximum temperature is an important variable and sometimes we forget about it. With extended heat and operation time, the wax may start to lose its characteristics. In short, above the maximum temperature, the wax inside the valve element is burned. Burning the wax makes it lose some physical features that allow expanding at a specific temperature.

Avalaible brands of thermostatic valve elements:

General contact

Driemanssteeweg 190
3084 CB Rotterdam
The Netherlands