You'll find a test plug somewhere on the regulator. Get a piece of 1/4"
poly tubing and nail [staple?] it on a board to make a 'U' tube
manometer about 18" long. Connect to the test plug with a tubing
adaptor. fill the U-tube 1/2 full of water. turn on the gas pressure.
Measure the pressure differential at the water surfaces in the U-tube.
Should be 11". If you want to get fancy put some red food coloring in
the water.
Bugs