Danfoss POV Compressor Overflow Valve Installation Guide
- June 3, 2024
- Danfoss
Table of Contents
POV Compressor Overflow Valve
Installation Guide
POV Compressor Overflow Valve
Installation
Installation
Note!
Valve type POV is categorized as a compressor overflow 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 (CO₂).
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 barg (580 psig).
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.
Only materials and welding methods compatible with the valve housing material
must be applied. 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.
Danfoss A/S
Climate Solutions
danfoss.com
+45 7488 2222
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