Manometer for pressure pmax ≤ 50 mbar

Table of Contents


Measuring Range
(over- / underpressure)
0 to 10 mbar0 to 20 mbar0 to 40 mbar0 to 50 mbar
Resolution0.1 mbar0.1 mbar0.1 mbar0.1 mbar
Dimensions190 x 40 x 15 mm305 x 40 x 15 mm540 x 40 x 15 mm650 x 40 x 15 mm
Weight0.30 kg0.40 kg0.62 kg0.72 kg


The Manometer can be used for measurement of the gas pressure while measuring the gas flow. Among other reasons, this is necessary if the measured and indicated actual volume of gas must be recalculated into the norm volume. The actual volume is the volume at the actual temperature and the actual pressure.

The norm volume of a gas is the volume at norm conditions which are (in Germany):

Norm Temperature= 273.15 Kelvin ( = 0 °C)
Norm Pressure= 1,013.25 mbar

The formula for converting the actual volume into norm volume is:

formel gasgleichung tg
VN=Norm Volume in(ltr)
Vi=Indicated Volume in(ltr)
pN=Norm Pressure in(mbar–absolute)
pa=Actual Pressure in(mbar–absolute)
TN=Norm Temperature in(Kelvin)
Ti=Indicated Temperature in(Kelvin)

Note: The indicated gas pressure at the manometer is the differential pressure between the gas pressure at the gas inlet and the actual atmospheric air pressure. Thus, the actual gas pressure (pa) of the above formula equals the indicated gas pressure at the Manometer plus the actual atmospheric air pressure in (mbar).


Unpack the Manometer. Mount the Manometer into the Manometer support. Unscrew the closing cap of the »Manometer Connection« port located at the »Gas Inlet« nozzle at the center of the rear plate. The removed closing cap of the port can be stored easily by screwing it onto the respective thread support at the rear side of the Manometer. Screw the closing cap, which is attached to the flexible Manometer pipe, tight to the »Manometer Connection« port.

Filling the Manometer

The Manometer is to be filled with the blue Special-Equipment Filling Oil (»Spezial-Gerätefüllöl«) provided with the Manometer. First remove the white thumb screw from the Filling Hole. Pour in the Oil until the Oil column reaches the »0«-mark on the front of the Manometer. Replace the white thumb screw. Please note: Only the specially provided blue oil should be used with this Manometer (Density 0.88)! If the manometer is filled with an oil with a different density, the Manometer indication will inevitably be wrong.
Then, unscrew the closing cap of the »Manometer Connection« port located at the Gas Inlet nozzle (on the rear side of the Gas Meter casing). The removed closing cap of the port can be stored easily by screwing it onto the thread support on the rear of the Manometer. Lastly, tightly screw the closing cap attached to the flexible Manometer tube, onto the »Manometer Connection« port. The Manometer is now ready for use.

Reading the Manometer

The oil column of the Manometer indicates the differential pressure in (mbar) of the gas between the Gas Inlet of the Gas Meter and the atmospheric pressure.

Caution: If the Manometer is connected to the gas inlet of the Gas Meter but not filled with oil, gas will leak through the Manometer. This will inevitably cause a measurement error of the Gas Meter.

V 2.1 / Rev. 2024-02-07 / Subject to alterations.