Disclaimer: Propane is flammable. The information provided here is *general information* culled from the web. I cannot be held responsible if you blow yourself up or burn off your face or someone else’s.
The “Stay-a-while” type adapters simply add two ports to your existing propane supply line, and cost around $30 at the time of this posting. The Stanbroil version pictured above actually calls it what it is: a brass tee with 4 ports. Theses adapters go just after the propane tank but BEFORE the regulator, and are thus for HIGH PRESSURE. Usually one port is a disposable one pound container fitting (1″-20), and the other is a threaded quarter inch inverted flare fitting (both attached to the tee via 1/4 male pipe threads). I swapped the 1/4″ inverted flare on mine for the QCC fitting typically used to connect back to the supply line, so the QCC port is now available for an external tank connection. I left the “disposable 1lb. tank” connector for hooking up external high pressure appliances like camping stoves that normally use the small disposable tanks. I then made my own supply hose to go from QCC to QCC (i.e. To connect a typical tank with the “big threads” to the “big threads” now on my RV supply line.
Some useful information…
POL is short for Prest-o-lite, the company that first started manufacturing this connection. POL is the connection that utilizes the INSIDE thread. A POL connection usually requires a wrench to get the connection tight enough to prevent leaking.
QCC stands for Quick Closing Coupling. A QCC connector uses the giant external threads you typically see on a 20# propane BBQ tank. The big plastic nut part of the QCC connector is often called an Acme Nut and is what threads onto the big QCC threads.
The pressure coming out of a propane tank when the ambient temperature is 100 degrees Fahrenheit is around 172 PSI.
Low pressure propane quick-connects are to be used AFTER a regulator.
A propane supply line quick connect must be High Pressure, not the low pressure rated ones typically marketed for RV’s and available from brands like Camco and Mr. Heater. These low pressure accessory quick connects are labeled as being made for 1/2 psi (low pressure) lines.