VAG Operation and Maintenance Instructions • 5
4.1 Conditions required on site
When installing the pipeline flange it must be horizontal, plane pa-
rallel and flush.
Aeration and venting valves should be installed as
close as possible to the pipe being vented to avoid
long supply lines from collect-ing stagnating water
(hygienic problems, higher costs, regular flushing). In
addition, long supply lines may result in limited venting
function as well as be associated with the risk of free-
zing (the supply line or the air valve itself).
In case of mechanical works around the valve causing dirt (e.g.
painting, working with concrete etc.), the valve must be protected
by adequate covering.
For assembly in drinking water pipelines, suitable sealing mate-
rials, lubricants and process materials must be used which are
approved for use in drinking water pipelines.
Before putting the valve into operation, clean and purge the corre-
sponding pipeline sections.
4.2 Installation location
To ensure the trouble-free function and long service life of the val-
ve, several factors have to be taken into account when positioning
the valve.
The VAG DUOJET
®
Automatic Air Valve can be installed in sta-
tions, in the open or in chambers.
4 Installation into the pipeline
3.3.4 Air release valve performance data
The small venting cross-section is for venting small amounts of air
during operation under full internal overpressure.
Picture 6: Air release – small cross-section
Installation should take place at the high points of the pipeline. For
direct installation of the VAG DUOJET
®
Automatic Air Valve on a
standpipe we recommend the use of an orifice plate upstream
of the valve. Chamber structures must be built and equipped in
accordance with DVGW data sheet W 358.
4.2.1 Installation in pipeline < DN 600
For pipelines < DIN 600 it is wise to use a sufficiently dimensioned
venting dome. If not verified in detail, the venting dome can be
considered sufficiently dimensioned if its construction height mat-
ches the diameter of the pipeline and has the diameter of approxi-
mately half the diameter of the pipeline. A central stop valve, an air
valve and, if required, a device for manually activated aerating and
venting or flushing are required. The central stop valve upstream
from the air valve allows it to be installed or dismantled without
interrupting operations. Because the air valve stopped by the stop
valve is under pressure a vent plug is provided on the air valve to
release pressure. In place of a plug, an installed valve operated
manually simplifies aeration and venting and can also be used as
a flush valve.
Picture 7: Pipeline < DN 600
~ DN
~ 0,5 DN
1
2
3
1
: Venting valve
2
: Manually operated air inflow and release, flush
valve
3
: Central stop valve
