2
DKRCI.PI.KD1.A1.01 / 520H5935
© Danfoss A/S (AC-SMC/MWA), 01-2012
ENGLISH
Installation
Refrigerants
Applicable to all refrigerants, including H
2
S
and flammable hydrocarbons and non-
corrosive gases or liquids, with due
consideration given to valve materials.
Pressure and temperature range
SVA-S/L (DN 15-65) 52 bar (754 psi) at
–50°C/+50°C (–58°F/+122°F)
SVA-S/L (DN 80-200) 50 bar (725 psi) at
–50°C/+50°C (–58°F/+122°F)
Installation
The valve must be installed with the
spindle vertically upwards or in horizontal
position (fig. 1). Valves should be opened
by hand without the use of tools or other
devices (fig. 3). The valve is designed to
withstand a high internal pressure.
However, the piping system should be
designed to avoid liquid traps and reduce
the risk of hydraulic pressure caused by
thermal expansion. It must be ensured that
the valve is protected from pressure
transients like “liquid hammer” in the
system.
Attention!
SVA are shut off valves and must always be
either fully closed or fully open. Half open
positions are not allowed.
Recommended flow direction
To achieve optimum flow conditions, the
valve should be installed with the flow
towards the valve cone as indicated by the
arrow on the side of the valve body
(fig. 2). Flow in the opposite direction is
also acceptable (fig. 2), but slightly reduces
the k
v
- / C
v
value.
Welding
The bonnet should be removed before
welding (fig. 4) to prevent damage to the
sealing parts in the packing gland and
between the valve body and bonnet, as
well as the teflon gasket in the valve seat.
Only materials and welding methods,
compa-tible with the valve housing
material, must be welded to the valve
housing. The valve should be cleaned
internally to remove welding debris on
completion of welding and before the
valve is reassembled.
Avoid welding debris and dirt in the
threads of the housing and the bonnet.
Removing the bonnet can be omitted
provided that:
The temperature in the area between the
valve body and bonnet during welding
does not 150°C/+302°F. This
temperature depends on the welding
method as well as on any cooling of the
valve body during the welding itself.
(Cooling can be ensured by, for example,
wrapping a wet cloth around the valve
body.) Make sure that no dirt, welding
debris etc. get into the valve during the
welding procedure.
Be careful not to damage the teflon cone
ring.
The valve housing must be free from
stresses (external loads) after installation.
Stop valves must not be mounted in sy-
stems where the outlet side of the valve is
open to atmosphere. The outlet side of the
valve must always be connected to the
system or properly capped off, for example
with a welded-on end plate.
Assembly
Remove welding debris and any dirt from
pipes and valve body before assembly.
Check that the cone has been fully screwed
back towards the bonnet before it is re-
placed in the valve body (fig. 5a).
vTightening
Tighten the bonnet with a torque wrench,
to the values indicated in the table
(fig. 5b).
Colours and identification
The SVA valves are painted with a red oxide
primer in the factory. Precise identification
of the valve is made via the ID ring at the
top of the bonnet, as well as by the
stamping on the valve body. The external
surface of the valve housing must be
guarded against corrosion with a suitable
protective coating after installation and
assembly.
Protection of the ID ring when repainting
the valve is recommended.
Maintenance
Packing gland
When performing service and mainte-
nance, replace the complete packing gland
only, which is available as a spare part. As a
general rule, the packing gland must not
be removed if there is internal pressure in
the valve. However, if the following
precautionary measures are taken, the
packing gland can be removed with the
valve still under pressure:
Backseating (fig. 6)
To backseat the valve, turn the spindle
counter-clockwise until the valve is fully
open.
Pressure equalization (fig. 7)
In some cases, pressure forms behind the
packing gland. Hence a handwheel or
similar should be fastened on top of the
spindle while the pressure is equal-ized.
The pressure can be equalized by slowly
screwing out the gland.
Removal of packing gland (fig. 8)
Handwheel and packing gland can now be
removed.
Dismantling the valve (fig. 9)
Do not remove the bonnet while the valve
is still under pressure.
Check that the flat gasket (pos. A) has
not been damaged.
Check that the spindle is free of
scratches and impact marks.
If the teflon cone ring has been
damaged, the whole cone assembly
must be replaced.
Replacement of the cone (fig. 9)
Unscrew the cone screw (pos. B) with an
Allen key.
SVA-S/L 15-40 ................................... 2.0 mm A/F
SVA-S/L 50-65 ................................... 2.5 mm A/F
SVA-S/L 80-100 ....................................4 mm A/F
SVA-S/L 125-150 .................................5 mm A/F
SVA-S/L 200...........................................6 mm A/F
(An Allen key is included in the Danfoss
Industrial Refrigeration gasket set).
To remove the balls compress the disk
spring (pos. D) and remove the balls (pos.
C).
Number of balls in pos. C:
SVA-S/L 10-20 .............................................10 pcs.
SVA-S/L 25-65 .............................................14 pcs.
SVA-S/L 80-200 .........................................13 pcs.
The cone can then be removed. Place the
new cone on the spindle and remember
to place the disk spring (pos. D) between
the spindle and the cone. Compress the
the disk spring and replace the balls (pos.
C). Refit the cone screw in again using
Loctite No. 648. to ensure that the screw is
properly fastened.
Replacement of backseat seal (fig. 10)
For sizes DN 80-200 only:
The valve backseat is a special teflon ring. If
this is damaged, it must be replaced. Screw
the spindle out of the bonnet. Carefully
remove the original backseat seal and
mount a new one in the angled contact
surface directly inside the opening in the
bonnet. Avoid folding and damage to
the teflon ring, or damage to the contact
surface at the top of the valve during
assembly.
Assembly
Remove any dirt from the body before the
valve is assembled. Check that the cone
has been screwed back towards the bonnet
before it is replaced in the valve body
(fig. 5a).
Tightening
Tighten the bonnet with a torque wrench,
to the values indicated in the table (fig. 5b).
Tighten the packing gland with a torque
wrench, to the values indicated in the table
(fig. 11).
Use only original Danfoss parts, including
packing glands, sealing parts and gaskets
for replacement. Materials of new parts are
certified for the relevant refrigerant.
In cases of doubt, please contact Danfoss.
Danfoss accepts no responsibility for
errors and omissions. Danfoss Industrial
Refrigeration reserves the right to make
changes to products and specifications
without prior notice.
