VAG Operation and Maintenance Instructions • 8
4.5 Assembly instructions and fittings
Check the valve for possible damage that it may have suffe-
red during transport and storage. Protect the valve against dirt
caused on the construction site by adequate covering until ins-
tallation. Thoroughly clean the surface of the flange gasket prior
to installation.
VAG does not assume any liability for consequential damage
caused by dirt, shot-blasting gravel residue etc.
The functional parts should be checked for proper operation prior
to installation.
Should the valves be repainted later on, it must be ensured that
no paint is applied to the functional parts. The identification plates
must not be painted over either. If the equipment is sand-blasted
for cleaning prior to installation, these parts must be adequately
covered. If solvents are used for cleaning, it must be ensured that
the solvents do not destroy the seals of the pipeline or the valve.
For the assembly of the VAG DUOJET
®
Automatic Air Valve it
must be ensured that proper load suspension devices as well as
means of transport and lifting devices are available.
When connecting the valve with the pipeline flanges, hexagon
bolts and nuts with washers from flange to flange must be used
in the through holes.
The bolts and nuts selected by the operator must be appropriate
for the pressure, temperature, flange material and the gasket. For
connections that contain at least one cast-iron flange it is recom-
mended to use bolts with a yield strength not exceeding 240 N/
mm².
Fasten the bolts evenly and diagonally to prevent unnecessary
tension and the resulting cracks or breaks.
We recommend using steel-reinforced rubber seals to DIN EN
1514-1 Shape IBC. If you use raised face flanges, these seals are
mandatory.
5 Set-up and operation of the valve
5.1 Visual inspection and preparation
Before putting the valve and the equipment into operation, per-
form a visual inspection of all functional parts. Check whether all
bolted connections have been properly fastened.
If there is an upstream stop valve this must be set to the open po-
sition so that the VAG DUOJET
®
Automatic Air Valve can function
satisfactorily.
5.2 Function check and pressure test
Warning:
The pressure exerted on the closed valve
must not exceed its nominal pressure (see technical
data sheet KAT 1912-A).
Newly installed pipeline systems should first be thoroughly pur-
ged to remove all foreign particles. If residue or dirt particles are
present in the pipeline, they may clog the installation while the
pipeline is being purged. This may impair the function of the valve
or even block it.
In particular after repair work or upon the commissioning of new
equipment, the pipeline system is to be purged again with the val-
ve being fully open. If detergents or disinfectants are used it must
be ensured they do not attack the valve materials.
6 Maintenance and repair
6.1 General safety instructions
Prior to beginning inspection and maintenance work on
the valve, the connection to the pressure carrying pipe-
line must be shut off and depressurized via the plug on
the valve. Only afterwards may maintenance work on
the valve be performed.
After completing the maintenance works and before resuming
operation, check all connections for proper fastening and tight-
ness. Perform the steps described for initial set-up as described
under Section 5 “Set-up and operation”.
Statutory and local provisions as well as the safety and accident
prevention regulations must be observed and complied with at all
times.
Servicing, maintenance and inspection work as well as the repla-
cement of spare parts must only be carried out by qualified staff.
The plant operator is responsible for determining the suitability of
the staff or for ensuring the relevant qualifications.
In case the operator’s employees do not have the qualifications
required, they need to attend a training course. This training
course can e.g. be held by VAG Service employees.
In addition to this, the plant operator needs to ensure that all em-
ployees have understood these Operation and Maintenance Inst-
ructions as well as all further instructions referred to in them.
Protective equipment such as safety boots, safety helmets, gogg-
les, protective gloves etc. must be worn during all work requiring
such protective equipment or for which such protective equip-
ment is prescribed.
Improper or wrong use of the valve should be avoided. Prior to the
performance of any work on the valve and equipment it must be
ensured that the relevant pipeline section has been depressurised
and/or de-energised.
6.2 Inspection and operation intervals
The VAG DUOJET
®
Automatic Air Valve is virtually maintenance-
free.
The valve should however be inspected within a period of one
year (DVGW data sheet W 392).
Under extreme conditions of use this inspection interval should be
carried out more frequently.
Before any maintenance work is performed on the VAG DUOJET
®
Automatic Air Valve, the valve must be shut off by an inspection
valve and must be depressurised using the threaded plug 11 (see
Section 6.3.1. “Design”).
