A manometer is an instrument that is used for monitoring current pressure in a heating or cooling system at a given location. The pressure is often shown as relative to atmospheric pressure but can be shown as an absolute pressure.

Manometres are installed in those locations where it is necessary to know the pressure level, e.g. a component connection that requires regular pressure-level checks, or the pressure level on either side of a filter to indicate if the filter needs cleaning.

There is often a tendency to fit manometres out of habit and not from any real identified requirement. This means that a large number of pressure gauges are fitted unnecessarily, which takes up servicing and maintenance resources.

Manometres should be installed so that they are easily readable and should be fitted with an isolation valve.