A gas test gauge is a device used to determine the pressure of gas installations such as gas meters and boilers.
Gas test gauges are sometimes referred to as manometers or u-tube gauges.
Gas test gauges are used by gas and heating engineers during gas safe tests to check that gas appliances are working at the correct pressure.
They are also useful for checking new pipework for leaks before gas is distributed throughout the system.
A gas test gauge consists of a U-shaped tube filled with fluid which is fitted into a plastic case.
One end of the tube is connected to the appliance being tested by a rubber hose and the other is open to the atmosphere.
The pressure of the gas inside the appliance displaces the fluid in the tube. This displacement is indicated on the scale that runs along the length of the gauge.
The scale of a gas test gauge is marked in millibars (mbar). Every 10mm on the scale represents 1mbar.
For example, a 300mm long gas test gauge is able to measure pressures up to 30 mbar.
Gauges are available in a number of different lengths from 300mm (12 inches) to 1200mm (48 inches) and are able to measure pressures up to 30 mbar, 60 mbar, 90 mbar or 120 mbar.