There is a gas shutoff internal to the pigtail. If there is an indication of a leak, the tank's pigtail is designed to shut off the flow.
If a tank is opened too fast and the lines are empty, the tank may think there is a leak and shut off to a trickle. MAKE SURE everything that uses propane is off and then:
The solution is to close the valves on the tanks and wait 5 minutes. SLOWLY CRACK the tank valve (count to 10 as you open 1/4 turn). You should hear a slow hiss as the valve cracks.
Open and light a range burner and it should stand tall and blue. It may take a while if the lines need to be purged. You may also need to do the open tank slow procedure again.
Lou and Laura with Bella - German Short Hair Pointer
2008 GMC Sierra 2500HD Crewcab SB Allison Duramax
2010 Flagstaff 8526RLWS - Superglide 3300
HAM CALLSIGN - KC3FFW