Only the pressure relief valve as far as i see. Never noticed the bleeder screw, wonder where that vents to. Ill have to try it one day.I believe this link can help you with the different 'vents'.
The one they call the bleeder, manually operated, is not the pressure relief
here's a pic
At absolute bestWondering if it’s feasible to refill/transfer propane to an empty 20 lbs tank from a full 20 lbs tank?
Asking for a friend.
When traveling and a tank(s) run out miles and miles from the nearest refill station. Instead of swapping out with spare tank(s), using a spare to refill the tongue mounted tank(s).
His friend could wrap the tank he is filling in ice and heat the other tank, by sunlight, hot water or heating pad (no not a torch). In my friend's experience, he could probably get maybe max of 60% in the empty tank (probably closer to 55% in reality) Not sure if its worth it though. Not usually a quick process (probably quicker to switch the tanks after all said and done) and there are the possibility of bad things happening. If parked and not traveling, an extension hose to the new tank is probably the easiest.At absolute best
you'dyour friend, would end up with two 20 lb tanks with 10 lb propane each.
The pressure in the 'full' tank would push liquid (tank situated with outlet valve low) or gas (tank in upright position) into the lower pressure, 'empty' tank only until the pressure was equal. Then the flow/transfer stops.
You'dYour friend would also lose the small amount of fuel (gas or liquid) remaining in the interconnect hose when that was removed.
Is your (friend's) tongue tank mount that time consuming to justify disconnecting (but not removing / exchanging) the empty tank to gain a partial fill?