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Installation
Refrigerants
Applicable to HCFC, HFC, R717 (Ammonia),
R744 (CO
), Propane, Butane, Iso-Butane and
2
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 (752 psi)
Please see the technical brochure
(DKRCI.PD.F00.A) for a more detailed
description of the pressure and temperature
range.
The valve must be installed with the spindle
on top vertically upwards or in horizontal
position ( g. 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 ow towards the cone as indicated
by an arrow on the valve housing ( g. 1).
Welding
To prevent damage to the sealing parts in the
packing gland and between the valve body
and bonnet, as well as the te on gasket in the
valve seat, the bonnet should be removed
before welding and protect it from dirt and
moisture ( g. 2).
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.
Be careful not to damage the te on cone ring.
The valve housing must be free from stresses
(external loads) after installation.
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 o , 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) ( g. 3).
© Danfoss | DCS (MWA) | 2018.01
Important for the SCA-X valves:
Full capacity is only obtained when the
spindle is screwed outward, "into bonnet", i.e.
counterclockwise ( g. 3).
Tightening
Tighten the bonnet with a torque wrench, to
the values indicated in the table ( g. 3).
Please note that the table ( g. 3) containing
maximum torque must be adhered to and
never exceeded.
Important for SCA-X/CHV-X 50 - 125 valves:
For optimal ow the insert must be installed
as indicated in ( g. 10). Otherwise kv value
will be below indicated in the
technical brochure.
Colours and identi cation
The SCA-X and CHV-X valves are painted
with a red primer in the factory. Precise
identi cation 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 ( g. 4)
To backseat the valve, turn the spindle
counterclockwise until the valve is fully open.
Pressure equalization ( g. 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 ( g. 6)
Packing gland can now be removed.
Dismantling the valve ( g. 8)
Do not remove the bonnet while the valve is
still under pressure.
DN 15-40 ( g. 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 te on cone ring has been damaged,
the whole cone assembly must be
replaced.
DN 50-125 ( g. 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 te on cone ring (pos. D) has been
damaged, the whole cone assembly must
be replaced.
Replacement of the cone ( g. 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.
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 ( g. 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 ( g. 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
( g. 3).
Tightening
Tighten the bonnet with a torque wrench,
to the values indicated in the table ( g. 3).
Tighten the packing gland with a torque
wrench, to the values indicated in the table
( g. 7).
Use only original Danfoss parts, (including
packing glands and gaskets) for replacement.
Materials of new parts are certi ed for the
relevant refrigerant.
In cases of doubt, please contact your local
Danfoss sales o ce.
DKRCI.PI.FL1.S5.ML | 520H8310 | 4
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