Danfoss SCA-X 15 Installationsanleitung Seite 2

Installation
Refrigerants
Applicable to HCFC, HFC, R717 (Ammonia), R744 (CO2), 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,
© Danfoss | Climate Solutions | 2022.10
ENGLISH
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.
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