Observing the test kit gauge needle holding steady after introducing high pressure water downstream of the second check valve at test cock cock number four and closing test cock number two only indicates that there is no downstream demand. If the test kit needle holds steady this is an indication that the backflow prevention device assembly is in a static state. It does not indicate that the downstream shut-off valve (number two shut-off valve) is drip tight. Also to confirm that the second check valve is holding drip tight against backpressure, test cock number should be open. If test cock number two is closed how is high pressure getting to test cock number four to backpressure the second check valve. After applying high pressure water downstream of the second check valve one should observe the relief valve port. If water does not discharge out of the relief valve and there is no downstream demand, the second check valve is considered drip tight with backpressure. If water discharges continuously out of the relief valve when applying backpressure to the downstream side of the second check valve, this is an indication that the second check valve is not hold drip tight against backpressure. (Disc compression should be taken into consideration if a discharge is noted but stopped.) When evaluating the first check valve the actual differential pressure reading should be recorded on the test report form.
A very nice and extensive explanation of the procedure reiterating what the ASSE 5000 says. I hope this helps explain better than when we read it from. The book.
Observing the test kit gauge needle holding steady after introducing high pressure water downstream of the second check valve at test cock cock number four and closing test cock number two only indicates that there is no downstream demand. If the test kit needle holds steady this is an indication that the backflow prevention device assembly is in a static state. It does not indicate that the downstream shut-off valve (number two shut-off valve) is drip tight. Also to confirm that the second check valve is holding drip tight against backpressure, test cock number should be open. If test cock number two is closed how is high pressure getting to test cock number four to backpressure the second check valve. After applying high pressure water downstream of the second check valve one should observe the relief valve port. If water does not discharge out of the relief valve and there is no downstream demand, the second check valve is considered drip tight with backpressure. If water discharges continuously out of the relief valve when applying backpressure to the downstream side of the second check valve, this is an indication that the second check valve is not hold drip tight against backpressure. (Disc compression should be taken into consideration if a discharge is noted but stopped.) When evaluating the first check valve the actual differential pressure reading should be recorded on the test report form.
A very nice and extensive explanation of the procedure reiterating what the ASSE 5000 says. I hope this helps explain better than when we read it from. The book.