Installation; Maintenance - Danfoss SVA-S SS 15 Installation Manual

ENGLISH

Installation

Refrigerants
Applicable to HCFC, HFC, R717 (Ammonia),
R744 (CO ) and all flammable refrigerants.
2
The valve is only recommended for use in closed
circuits. For further information please contact
Danfoss.
Pressure and temperature range
SVA-S/L SS (DN 15-65) 52 bar (754 psi)
SVA-S/L SS (DN 80-125) 50 bar (725 psi) at
–60°C/+150°C (–76°F/+302°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-S/L SS 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 - / C value.
v v
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.
Be careful not to damage the teflon cone ring
and make sure the complete bonnet is protected
from dirt and water while removed.
Removing the bonnet can be omitted provided
that: The temperature in the area between the
valve body and bonnet during welding does not
exceed +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.
Only materials and welding methods,
compatible with the valve housing material,
must be welded to the valve housing. The valve
housing must be free from stresses (external
loads) after installation.
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.
Do NOT remove or service the dark colored
grease between the spindle thread and the
bonnet. In case the grease has been
contaminated with dirt, debris, particles or water
the complete top part must be replaced.
© Danfoss | DCS (MWA) | 2018.05
Stop valves must not be mounted in systems
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 replaced in the valve body
(fig. 5a).
Tightening
Tighten the bonnet with a torque wrench, to the
values indicated in the table (fig. 5b).
Please note that the table (fig. 5b) containing
maximum torque must be adhered to and never
exceeded.
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 SS 15-40 ........................................ 2.0 mm A/F
SVA-S/L SS 50-65 ........................................ 2.5 mm A/F
SVA-S/L SS 80-100 .........................................4 mm A/F
SVA-S/L SS 125 ...............................................5 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 SS 15-20 ..................................................10 pcs.
SVA-S/L SS 25-65 ..................................................14 pcs.
SVA-S/L SS 80-125 ..............................................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 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.
Do NOT remove or service the dark colored
grease between the spindle thread and
the bonnet. In case the grease has been
contaminated with dirt, debris, particles or water
the complete top part must be replaced.
Replacement of backseat seal (fig. 10)
For sizes DN 80-125 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).
Please note that the table (fig. 5b) containing
maximum torque must be adhered to and never
exceeded.
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.
DKRCI.PI.KD3.A5.ML | 520H8209 | 2