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Questions about VAG Non-return Valves
Choose a question:
At which pressure does the VAG-SKR open and when is the valve fully open?
Where can I find Zeta values for the non-return valves?
Are VAG's non-return valves DVGW certified?
Can VAG's non-return valves be used in combination with drinking water?
When should which non-return valve be used?
At which pressure does the VAG-SKR open and when is the valve fully open?
When the inlet pressure (in mm WS) corresponds to the nominal diameter (i.e. for DN 300), the SKR needs a maximum of 300 mm WS to get out of the seat.The SKR is fully open when the speed reaches approximately 1.5 m/s.
The valve should be fully open to guarantee error-free operation.
If the flow velocity is lower, the pipe must be contracted and a smaller SKR used.
Where can I find Zeta values for the non-return valves?
They are included in USE CAD (CD or internet).
Not only are Zeta values provided for open valves, the flow rate can be used to determine the pressure loss at intermediate positions.
Are VAG's non-return valves DVGW certified?
No, because DVGW still has to establish the German testing principles.
Can VAG's non-return valves be used in combination with drinking water?
Yes, the rubber parts and coating are KTW certified.
When should which non-return valve be used?
Non-return valves should be selected according to their use, i.e. drinking water, wastewater, heat medium, risk of pressure surge and so forth.
General selection criteria are:
- Drinking water up to DN 150 RETO-STOP
- from DN 200 SKR
- Risk of pressure surge to DN 300 TOP-STOP
- from DN 350 SKR with damper
- Wastewater Ball check valve
- Hot water RSK swing check valve