© Danfoss | DCS (MWA) | 2018.05
DKRCI.PI.FL1.T2.ML | 520H6172 | 4
ENGLISH
Installation
Refrigerants
Applicable to HCFC, HFC, R717 (Ammonia),
R744 (CO
2
), Propane, Butane, Iso-Butane and
Ethane.
The valve is only recommended for use in
closed circuits. For further information please
contact Danfoss.
Temperature range
–60/+150°C (–76/+302°F)
Pressure range
52 bar (754 psi)
The valve must be installed with the spindle
on top vertically upwards or in horizontal
position (fig. 1). SCA-X valves should be
opened by hand without the use of tools
or other devices. 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.
Flow direction
Direct the flow towards the cone as indicated
by an arrow on the valve housing (fig. 1).
Welding
The bonnet should be removed before
welding (fig. 2) to prevent damage to the
O-rings in the packing gland and the gasket
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.
Only materials and welding methods,
compatible with the valve housing material,
must be applied 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.
Stop check 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 repositioned
in the valve body (SCA DN 50-125) (fig. 3).
Important for the SCA-X valves:
Full capacity is only obtained when the
spindle is screwed outward, “into bonnet”, i.e.
counterclockwise (fig. 3).
Tightening
Tighten the bonnet with a torque wrench, to
the values indicated in the table (fig. 3).
Please note that the table (fig. 3) containing
maximum torque must be adhered to and
never exceeded.
Important for SCA-X/CHV-X 50 - 125 valves:
For optimal flow the insert must be installed
as indicated in (fig. 10). Otherwise kv value
will be below indicated in the
technical brochure.
Colours and identification
The SCA-X and CHV-X valves are painted
with a red primer in the factory. Precise
identification of the valve is made via the
green coloured 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 protected against corrosion
with a suitable protective coating after
installation and assembly.
Protection of the name plate when repainting
the valve is recommended.
Maintenance
Packing gland (only SCA-X types)
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. 4)
To backseat the valve, turn the spindle
counterclockwise until the valve is fully open.
Pressure equalization (fig. 5)
In some cases, pressure forms behind the
packing gland. Hence, a handwheel or a large
washer (pos. A) 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. 6)
Packing gland can now be removed.
Dismantling the valve (fig. 8)
Do not remove the bonnet while the valve is
still under pressure.
DN 15-40 (fig. 8a):
- Check that the gasket (pos. A+B) has not
been damaged.
- If the gasket (pos. A) has been exposed
to air or other refrigerants than listed in
this installation guide for more than
6 months it must be replaced.
- 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.
DN 50-125 (fig. 8b):
- Check that the spring (pos. A) is intact.
- Check that the gasket (pos. B+E) has not
been damaged.
- If the gasket (pos. A) has been exposed
to air or other refrigerants than listed in
this installation guide for more than
6 months it must be replaced.
- Check that the spindle (pos. C) is free of
scratches and impact marks.
- If the teflon cone ring (pos. D) has been
damaged, the whole cone assembly must
be replaced.
Replacement of the cone (fig. 9)
DN 15-40:
O-ring (pos. C) prevents the cone from falling
out. Pull the cone clear of the bonnet. Ensure
that the spring is not lost in the process.
Remove dirt, if any. Mount O-ring (pos. C) on
cone. Mount spring and cone in 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.
Assembly
Remove dirt, if any, from pipes and housing
before assembly. Important for the SCA-X
valves: Full capacity is only obtained when
the spindle is screwed outward, “into the
bonnet”, i.e. counterclockwise (fig. 3).
Note:
For SCA-X and CHV-X sizes DN 15-40 it
is important to ensure that the lower
and upper part of the insert is tightly
screwed together (fig. 11) and that this
screw connection is kept tight during
repositioning of the cone in the housing.
Use a torque wrench to tighten the bonnet
(fig. 3).
Tightening
Tighten the bonnet with a torque wrench,
to the values indicated in the table (fig. 3).
Tighten the packing gland with a torque
wrench, to the values indicated in the table
(fig. 7).
Use only original Danfoss parts, (including
packing glands and gaskets) for replacement.
Materials of new parts are certified for the
relevant refrigerant.
In cases of doubt, please contact your local
Danfoss sales office.
