Re: [A/S] OPD Propane Cylinder Conversion

[Charlie/Betty Burke <cbburke@xxxxxxxxxxxxx>]

Thank you for your comments.

Over the years there have been quite an assortment of LP tanks included with Airstream 
trailers. Currently available are Worthington built aluminum and steel tanks. The 
aluminum tanks are premium tanks and come with gauges. The steel tanks, typically used 
on the Safari series do not have gauges.

On the open market, Marshall along with others compete in the manufacture of steel 
tanks. Steel tanks can be purchased with and without gauges, both vertical and 
horizontal mount. Of course all this has been complicated by the OPD mandate.

If you wonder what kind of political clout Airstream owners have consider this.
The OPD requirement is for ALL DOT certified transportable tanks with a capacity of 10 
gallons (40 lb.) or less. Airstream has been almost the exclusive user of 40 lb 
Horizontal tanks since starting in the late 80's. Almost immediately after the mandate 
was published, the club started campaigning to modify it for the 40 lb horizontal 
tank. In less than three years, before the requirement became mandatory, they got the 
rules changed to allow the continued use of the existing 40 lb tanks. At the same time 
they campaigned Worthington to make an OPD compliant horizontal tank. Worthington
release the tank about the same time the rule was changed so they were no longer 
required. All of this without the support of Airstream who redesigned the LP system to 
eliminate the use of horizontal tanks.

The tank that Airstream uses that has a gauge is not just a gauge. The gauge also acts 
as a sending unit for the inside monitor panel. Most LP tank gauges commonly seen are 
gauges only (no wire terminals) and will not work on an RV inside monitor system. For 
the last ten years the sending unit gauges are rated at 90 Ohms.

One last thing to consider. Virtually all Airstream dual LP tank installations 
have/had an automatic changeover regulator. The regulator assures you do not have to 
ever run out of LP. Their operation is as follows:

1. Start with both tanks full and both tank valves open.
2. The regulator has a knob or lever that select one of the tanks
3. An indicator of some sort indicates whether the selected tank is empty (red) or has 
LP in it (green, gray etc.).
4. When the indicator changes color, the tank selected is empty and the regulator will 
start drawing from the other tank.
5. A periodic check of the indicator will let you know when a tank needs service.
6. When a tank is empty, change the selector to the opposite tank, close the empty 
tank valve, disconnect it, have it filled, remount and reconnect it, and reopen the 
valve. Return to step 4 and repeat as necessary.

Charlie

PS. Sorry for getting long winded.