There are several articles on the internet, RV and otherwise, about making your own water-column tester using clear tubing, a little liquid, and a ruler or marked back-board. http://www.rverscorner.com/manometer.html
is one of them.
Just remember the device is designed to measure a fraction of a psi. Connect it to a pressure tank, and you will have a fountain, not a gauge.
Originally Posted by Hex
. . . Does anyone know if one of the small propane containers (like for a burns-o-matic torch) will have enough pressure/volume to test the fridge or stove, or should I go and just buy myself a 20lb tank? (And no, I can't just steal the one from the grill, I'm strickly a lump charcoal guy.
You might as well go and get a 20 lb. tank. If the appliances work, you would eventually want one, anyway. I might test the stove with a torch bottle lash-up, but personally wouldn't risk the 'fridge without a regulator.
You can get a re-conditioned tank at the exchange places like the box stores or home centers even if you don't have one to trade. Just be aware, most of them, at least around here, sell you 15 lbs of propane in a 20 lb tank in order to make the price look good compared to a refill. You don't have to buy a brand-new empty tank for the price of a 3/4 full reconditioned exchange tank, and then buy the gas elsewhere on top of that cost.
When you empty the tank, if you refill the whole 20 lbs. at a propane dealer you will come out a little bit ahead compared with another swap, and it won't run empty quite as often. If you are going to be refilling the tank instead of swapping it, try to check the certification dates stamped on the swap-out tanks, and pick a tank with the most recent date you can find. After a number of years (12?), the tanks can't be refilled without being re-certified.
If you have friends or neighbors who are not of the charcoal persuasion, they may have old tanks with worn-out grills that they see no value in, and will give you. Even an out-of-date tank can be exchanged at most of the swap places, but if it has an old valve there will be an up-charge to swap it for one with a modern Overfill Protection valve. The old tank will get a new OPD valve when it is re-habbed.