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Installation
Note!
Valve type POV is categorized as
a pressure relief accessory (not
as a safety accessory). Hence a
safety valve (e.g. SFV) has to be
installed to protect the system
against excessive pressure.
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
POV: –50/+150°C (–58/+302°F)
Pressure range
The valves are designed for a max. working
pressure of 40 bar g (580 psi g).
Installation
The POV valve is used in conjunction with
the BSV back pressure independent safety
relief valve and is specifically designed for
protecting compressors against excessive
pressure (fig. 5).
See technical leaflet for further installation
instructions.
The valve should be installed with the
spring housing upwards (fig. 1). By
mounting of the valve it is important to
avoid the influence of thermic and dynamic
stress (vibrations).
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
The valve should be installed with the flow
towards the valve cone as indicated by the
arrow on fig. 2.
Flow in the opposite direction is not
acceptable.
Welding
The top should be removed before welding
(fig. 3) to prevent damage to the O-rings
between the valve body and top, as well as
the teflon gasket in the valve seat. Do not
use high-speed tools for dismantling and
reassembling. Be sure that grease on bolts
is intact before reassembling.
© Danfoss | DCS (MWA) | 2018.11
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 top.
Removing the top can be omitted provided
that:
The temperature in the area between
the valve body and top as well as in the
area between the seat and the teflon
cone during welding does not exceed
+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 cloth around
the valve body). Make sure that no dirt,
welding debris etc. get 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.
Assembly
Remove welding debris and any dirt from
pipes and valve body before assembly.
Tightening
Tighten the top with a torque wrench to
the values indicated in the table (fig. 4). Do
not use high-speed tools for dismantling
and reassembling. Be sure that grease on
bolts is intact before reassembling.
Colours and identification
Precise identification of the valve is made
via the ID label on the top, 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 label when painting
the valve is recommended.
In cases of doubt, please contact Danfoss.
Danfoss accepts no responsibility for
errors and omissions. Danfoss Industrial
Refrigeration reserves the right to make
changes to products and specifications
without prior notice.
AN14978643320301-000502 | 2
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