Originally Posted by Karsty
I guess I was able to answer my own question to some extent. Went out to the RV and dragged out the manual.
The valve on the far left is a "relief valve". Not sure what that is for though.
The the other one is "tank gauge and sender". Seems self explanatory I guess. I gather it allows the inside panel to be able to know what level or amount of propane is in the tank.
Thanks for any other information.
The tank on my older Roadtrek is a Manchester ASME spec propane tank for RV applications. In layman's, it's a heavier duty propane tank that was specifically designed for bumping down the road under my van. They're built to higher specs and tolerances than the 20lb. BBQ models. And because of that, they don't "expire" in the same way. However, you still need to maintain them to some extent.
The relief valve is to relieve excess pressure build up in the tank to avoid a catastrophic structural failure, or other propane system damage.
I used to get mine filled at Free Gas in Font Hill, just down the road from you. I prefer to deal with experts, rather than some hack at a gas station on a weekend. Not to scare you, but there are some interesting propane related stories on here and other forums, posted by folks who dealt with the latter, when refilling their tank.