It is important to note the operating temperature range when selecting a pressure switch for monitoring high temperature liquids or gases. However, keep in mind that the operating temperature for the device will usually be the temperature of the environment surrounding the switch. Since the process does not flow through the switch, the temperature of the process at the pressure switch can be much lower than the process temperature. Therefore, the rated temperature of the pressure switch can often be much lower than the temperature of the process.

Using a short length of tubing, known as a temperature stand-off, can isolate the pressure switch from the high temperature pressure media; therefore avoiding the expense of a special high temperature pressure switch. The chart below shows various lengths and diameters of tubing for stainless steel and brass that will limit the media temperature at the pressure switch to 0-180°F. This chart assumes the ambient temperature around the pressure switch is 100°F and the major source of thermal input is via the connecting tubing.

For example, a pressure switch that has a 180°F temperature rating and is installed with a 5" long standoff of 1/4" stainless tubing could have a  process temperature as high as 600°F according to this chart. If the actual process temperature were higher, the length of tubing would need to be increased accordingly.