Danfoss SCA-X Installation Manual page 4

ENGLISH
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
65 bar (942 psi)
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/Brazing
The bonnet should be removed before
welding/brazing ( g. 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 te on gasket in the valve seat.
Be careful not to damage the te on cone
ring and make sure the complete bonnet is
protected from dirt and water while removed.
Only materials and welding/brazing 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.
For valves with socket brazing DIN(SD) or
socket brazing ASME(SA) connections, it is
always recommended to clean connections
with cleaning agent and wrap wet cloth
during brazing ( g. 2b).
The valve should be cleaned internally
to remove welding/brazing debris on
completion of welding/brazing and before
the valve is reassembled. Avoid welding/
brazing 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 o , for example
with a welded-on end plate.
Assembly
Remove welding debris and any dirt from
pipes and valve body before assembly. Check
4 | AN07068641793902-001301
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).
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 yellow 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.
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 ( 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).
SCA-X DN 100-125 only
Max permissible pressure di erence for
closing/opening according to EN12284 which
is a of EN378-1:
The table in g. 12 states the maximum
pressures at which the valves can be operated
manually and tightness can be achieved.
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.
© Danfoss | Climate Solutions | 2024.09