© Danfoss | Climate Solutions | 2022.06
4 | AN14978641682001-000501
ENGLISH
Installation
Refrigerants
Applicable to HCFC, HFC, R717(Ammonia)
and R744 (CO
2
).
Flammable hydrocarbons are not
recommended. The valve is only
recommended for use in closed circuits. For
further information please contact Danfoss.
Temperature range
DSV: –50/+100°C (–58/+212°F)
Pressure range
DSV: The valves are designed for a max.
working pressure of 40 bar g (580 psi g).
Installation
Applied in connection with safety valves
(SFV) installation instruction for safety
valves must be followed. The DSV and the
two safety valves (SFV) are to be mounted
as indicated in fig. 10.
IMPORTANT
:
The inlet/outlet pipe dimensions must not
be smaller than those of the safety valves.
The valve must be installed with the
spindle 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.
Recommended flow direction (fig. 2)
To achieve optimum flow conditions, the
valve should be installed with the flow
as indicated by the arrow. Flow in the
opposite direction is also acceptable , but
slightly reduces the K
v
- / C
v
value.
Operating instructions (fig. 2)
When the spindle is turned clockwise the
inlet socket C is connected to outlet B.
When the spindle is turned anticlockwise
the inlet socket C is connected to outlet A.
Welding
If welding fittings are applied, these
should be dismounted during the welding
process. Welding directly on the valve
housing, the bonnet should be removed
(fig. 4) to prevent damage to the O-rings 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, compatible 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 clothe around the valve
body.) Make sure that no dirt, welding
debris etc. gets 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.
Double 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 safety valves, 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).
Colours and identification
The DSV 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
prevented 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
maintenance, 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 it stops.
Pressure equalization (fig. 7)
In some cases, pressure forms behind the
packing gland. Hence a hand wheel or
similar should be fastened on top of the
spindle while the pressure is equalized.
The pressure can be equalized by slowly
screwing out the gland.
Removal of packing gland (fig. 8)
The packing gland can now be removed.
- Check that the spindle is free of scratches
and impact marks.
- If the Teflon cone rings have been
damaged, the whole cone assembly
must be replaced.
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). Also check that the O-rings are free of
scratches and impact marks.
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. 9).
Use only original Danfoss parts, including
packing glands, O-rings and gaskets for
replacement. Materials of new parts are
certified for the relevant refrigerant.
In cases of doubt, please contact Danfoss.
