I am a little confused with the end of step 2. Instructions state
"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..."
I completed step 2 and after 12 hours my low pressure gauge dropped 3/4 to 1 psi (is this considered a lot)? Also the temperature got colder by 20° and ambient air temperature has been near 40° during test . Is this acceptable or is there a leak? Thanks
As Bettatail mentioned, it is the change in pressure that you are looking at (i.e. the pressure should not drop more than 12.5% of the original value. If your PSI was set at 30 PSI for example, you would not want it to drop to lower than ~26 PSI).
If your low pressure gauge dropped 75%, then you have a significant leak somewhere (or there may be something wrong with the second stage regulation if you are using a dual stage regulator).
Are you sure your working pressure dropped to 1 PSI? If so, it indicates a leak (or you are working with extremely low working pressures...why?)
You should ideally be testing your CO2 system in a stable temperature environment; having the temperature fluctuate 20 degrees (Celsius? Fahrenheit? I assume Fahrenheit...) and then having it operating at 40 (again...Celsius? Fahrenheit? Again, I assume Fahrenheit) is too large of a change to accurately determine whether the changes in pressure are due to a leak or just temperature fluctuations.
I would set the working pressure to ~30 PSI, set the CO2 setup indoors where the temperature is more stable, and then see if it changes over the course of 6 hours.