INFO

 Used to obtain pressure readings and perform leak tests with Presto-Tap LDS products installed after tank pressure has been reduced to approximately 10# by the first stage regulator and before the further reduction of system pressure to W.C. or Oz. levels by the second stage regulator (i.e., Presto-Tap #RV installed in first & second stage regulator taps and/or Presto-Tap #LPV). 

NFPA 54 Annex D Section D.4 Suggested Method of Checking for Leakage 

By inserting a 30 psi (207 kPa) pressure gauge on the downstream side of the first stage regulator, admitting normal operating pressure to the system and then closing the container valve. Enough pressure should be released from the system to lower the pressure gauge reading by 5 psi (34.5 kPa). The system should be allowed to stand for 3 minutes without showing an increase or a decrease in pressure gauge reading.