I've never had that problem, but I can see how it could happen. It's important to apply the tape to the threads only, with no overhang. Here's Don Casey's advice:
"When connecting the supply hose to the solenoid, an adapter is usually required. Wrap the threads of the solenoid end of the adapter with Teflon sealing tape. Do not use Teflon tape on the hose end. The rule is that when the threads form the seal, you need Teflon tape, but not when the seal is formed with a flare, O-ring, or other compression fitting."
Use nitrogen for the test and eliminate the temp variances. 1 lb loss in 15 minutes may not be able to be read on the gauge at 175 psi. The value you place on your life is the amount of time you allow for leak testing propane.
All gases will increase in volume with an increase in temperature, per Charles Law. Charles Law: V1/T1=V2/T2
V= volume
T= Temperature
Temperature must be in Kelvin.
To convert Farenheight to Kelvin.
K=(Fdeg+459.67)/1.8
__________________
Jon Caisson Bozeman
S/V Little Miss Magic, Pirates Cove, AL
Well, I am keeping it simple for now.
The system passes 15-30 minute tests ok, longer than that and temperature does play games with pressure, so I left that alone for now.
I will monitor the system as I am using it, see if it behaves any better or worse.
BTW, IMHO, the propane tanks need to have their valves closed unless you are using the propane. This was an issue with Ken Barnes...where he wasn't sure of what electrical equipment he could use after his knockdown, because he wasn't sure the propane system wasn't leaking.
__________________
Sailingdog Telstar 28
New England
You know what the first rule of sailing is? ...Love. You can learn all the math in the 'verse, but you take
a boat to the sea you don't love, she'll shake you off just as sure as the turning of the worlds. Love keeps
her going when she oughta fall down, tells you she's hurting 'fore she keens. Makes her a home.
—Cpt. Mal Reynolds, Serenity (edited)
If you're new to the Sailnet Forums... please read this POST.
I know, this is why my new propane locker was placed in the cockpit - for easy access, so that I won't have an excuse not to turn off the tank when done cooking or for the night.
I suppose the downside is that a tank is so close to everything, but on a boat it is kinda hard to keep things "far" anyway, what with limited space and all.
Guys... something is not adding up here.
The pressure should not drop until the tank is exhausted. The propane is in liquid-gas equilibrium in the tank, and the guage pressure will monitor the vapour pressure of the gas on top of the liquid. The vapour pressure is dependent only on tank temperature, and not content (well, not until it is about to run out that is).
Measuring the content of the tank is normally done by weight, with a spring balance. Pressure does not tell us much.
In English, to be inert is to be in a state of doing little or nothing.
In chemistry, the term inert is used to describe something that is not chemically active. The noble gases were described as being inert because they did not react with the other elements or themselves. It is now understood that the reason that inert gases are completely inert to basic chemical reactions (such as combustion, for example), is because their outer valence shell is completely filled with electrons. With a filled outer valence shell, an inert atom is not easily able to acquire or lose an electron, and is therefore not able to participate in any chemical reactions. For inert atoms or molecules, a lot of energy is involved before it can combine with other elements to form compounds. A high temperature and pressure is necessary, and sometimes requires the presence of a catalyst. Wikipedia
Nitrogen is an inert gas and is not chemically active.
The pressure guage is downstream of the tank valve, and its sole purpose is for testing the propane system for leaks when the manual tank valve is CLOSED. The guage is never used to measure the pressure in the tank, which as you correctly point out is largely meaningless information.
