This leak check is also a function check for Double stage Regulator.
(spray soap water test only for the reachable connection ports, if leaking is inside the regulator, soap water test is useless.
also, someone suggest dipping the whole system in water to test leak, don't even think about it, it is suicide if solenoid is 120V, or you will ruin the solenoid.)
A. Regulator handle completely loose(counter clockwise).
B. Connect the regulator to the co2 tank, make sure the connection is secured.
C. Turn on the CO2 tank release handle slowly, CO2 inject into regulator, the HP gauge reading should be at 800 psi.
D. Shut the CO2 tank release handle, now the reading on the HP gauge should be 800 psi also.
E. Wait 6 hours, if the reading is the same, first stage is good, go to second step.
If the psi lower but the tank--regulator(soap water test), CGA 320 nipple--regulator(soap water test) and HP gauge--regulator(soap water test) connection ports are 100% no leak, your regulator is toasted--the leaking is inside(leaking HP gauge, punched diaphragm, diaphragm seal broken, or the poppet valve between the first stage and second stage chambers is not completely sealed.)
continue from step one if success, now you have 800 psi of co2 isolated in the first stage chamber.
A. needle valve open.
B. Solenoid valve power off(shut).
C. Turn the regulator handle clockwise to charge the second stage chamber, fill to the regulator default outlet maximum.
D. Turn the regulator handle counter clockwise(completely loose).
E. Release the CO2 in the first stage chamber by turning loose the regulator-Tank connection screw(make sure the co2 tank is closed before you do this).
Now you have CO2 isolated in the second stage chamber.
F. Wait for 5-10 minutes(to ease the second stage diaphragm elastic issue, psi may drop right after the regulator handle turn loose, then it will stay), record the LP gauge psi reading.
G. Wait for 6 hours, if the new psi reading is within 1/8+ difference of original reading, go to step 3
If the psi lower a lot after 6 hours, redo step 2, soap water test on every reachable connection port(LP gauge--regulator, regulator--fittings, fittings--solenoid)
if leaking found, fix it
redo step 2.
no leak, go to step 3
if still leak.
Take out the solenoid, seal the outlet port of the regulator(make sure the sealed port has no leak)
redo step 2 without the solenoid.
if no leak, solenoid valve has issue.
if leaking still, regulator toasted.(similar problems as mentioned in step one)
A. connect the regulator back to the co2 tank, charge both stage charmbers(turn on the co2 tank release handle then the regulator handle, outlet psi set to your desire psi).
B. Turn on the solenoid valve.
C. Turn off the needle valve, soap water test, between the ports of solenoid and the needle valve.
D. Turn on the needle valve, soap water test for rest of the hose/NPT/hose barb connections.
E. if leaking found, fix it.
leak test and regulator functional check complete.
Add: For Step 2, G, after 6 hours, the LP gauge PSI reading may differ as much as 1/4 of the original reading, due to the diameter, and material of the second diaphragm(different elasticity coefficient) and outside temperature.
If the PSI reading is off more than 1/4 of original reading, it is definitely a leak.