Thermostatic Valve vs Electronic Sensing/Solenoid Valve for Temperature Control Solutions

The unique characteristics of a thermostatic valve are that temperature sensing, fluid control (open or closed loop) and valve position modulation are all inherently contained in the valve without the need for an external temperature transducer or external power. This has a tremendous advantage in a number of applications where the traditional solution requires a temperature sensor, amplifier, control electronics, solenoid valve and DC Power. The thermostatic valve is a highly reliable, repeatable, compact, low cost device for many fluid temperature control applications.

Aerospace & Defense Applications

Thermostatic actuators and valves have a long history of success meeting the tough demands of the aerospace & defense Industry. This includes attributes such as high reliability, compact size and weight, maintenance free, performance repeatability, self-actuated (no external power required) and many others. In addition to standard valve parts being machined with brass and stainless steel, valves can also be machined from other metals such as titanium, Inconel, Hastelloy, duplex stainless steel, plastics, etc.

Following are examples of applications where this technology's been used in the aerospace & defense industry:

  • Scald protection for commercial airplane galleys

  • Freeze protection for airplane lavatories

  • Freeze protection for cold water supply lines on military bases and naval shipyards

  • Electronics fluid cooling on military aircraft and land-based vehicles

  • Equipment enclosure temperature control

  • Electro-mechanical solenoid replacement in various fluid temperature control applications

  • Hydraulic fluid temperature control

  • Lube oil temperature control

  • Pump seal over-temperature relief

  • Thermal based permissive / safety latching mechanism

  • Temperature based fluid mixing applications

  • Linear (heated) actuator – supplying a high force in a small envelope

  • Actuators controlling various mechanisms based on temperature

  • Diverting fluid to one of two valve ports based on its temperature


Thermostatic (paraffin wax) technology has been around since 1936. Over the years it has found its way into a broad range of industries. The aerospace & defense industry has adopted it because it checks most of the boxes required in this demanding industry – high reliability, compact size, very repeatable, maintenance free, self-powered, higher power to size ratio, few moving parts, and long service life.

This article was written by Tom Ruggiero, Program Manager of Aerospace, Defense and Government Facilities Division, ThermOmegaTech (Warminster, PA). For more information, visit here .