Pressure switches are a vital part of many safety circuits, especially on burners, combustion systems and heaters. Switches are generally split into three categories; firstly, those that prove process air flow in a system, secondly, those that prove combustion air flow and finally, those that prove that the gas pressure to or from the system is within the correct range.

Process air switches may be dotted around the plant and can be mounted locally to the process fans or piped into the process ductwork.

Combustion air pressure switches are generally mounted on the burner unit or close to the combustion air fan, they can sense an air pressure or be mounted with two sensing points in order to measure pressure differential and hence air flow.

Gas pressure switches are generally mounted directly onto the burner gas valve assembly and measure pressure alone. The low gas pressure switch is usually sited before the gas valves and the high gas pressure switch after. It is quite common for gas pressure switches to be mounted directly onto Dungs multibloc valves.