We took our "new" Worthington gas cylinders to have OPD valves installed. They are equipped with gauges that our local propane guy had never seen before and was concerned about damaging in the process.
So, we called Worthington. Very helpful people for such a big company.
The official name of this gauge is ROCHESTER REMOTE GAUGE.
They were made originaly for Airstream according to Worthington. They are very $$$.
Here is the description and tips in making these remote senders work smoothly:
"The gauge itself is either bolted into the tank with four bolts or, more likely, screwed into the tank through a 1-1/4 in. opening so that the bolts cannot corrode and allow the gasket to leak. This device has a float inside the tank that floats at liquid level and operates a shaft through a set of gears that rotate a magnet inside the gauge. There can be either a dial chamber, which must be read by looking at the dial on the tank, or a dial chamber with a remote sender fastened onto the face of the gauge that sends an electrical signal to a monitor panel. This is a magnetic tracking dial chamber that follows the internal magnet of the gauge."
"The dial chamber or remote sender is fastened to the sight gauge itself. Some senders snap on to the gauge, and some use screws. On some chambers, one of the screws is a grounding stud. The other screw is connected to the wire that connects to the coach monitor panel. The receiver is more accurate if it is grounded to a good grounding terminal rather than depending on grounding through frame members of the RV. Over time, poor grounding can result, because a grounding nut screwed into a frame may rust or corrode and not allow proper grounding at the connection. The use of a star washer can help maintain a good ground connection. Also, dielectric compound can be used to help prevent corrosion from occurring at the connections exposed to moisture.
One end of the sender is pointed and one end is flat so that the unit can only be installed in one direction. The pointed end has an arrow that indicates the direction the float moves on gauge.
There are new senders with heat shrink wire connections to protect against corrosion. A magnet can be used to test the new style gauge without disconnecting the wire. This may require unsnapping the sender from the tank. Be sure to set the dial follower needle back to match the gauge sender magnet when installing this type of sender for the first time or when the sender has been removed (use a magnetic screwdriver or similar tool).
Caution should be used to avoid any possibility of a hot wire touching the sending device, as it could burn out the sender. The senders used in almost all recreation vehicles are rated 0 to 90 Ohms. There are a variety of these Ohm resistance devices used by different vehicles. It is important to use the correct . resistance sender for your unit to be calibrated accurately. The back of the sender has the resistance inscribed in black letters."
on a related subject: While we had them on the phone, we talked about OPD valves.
They are using several makers, 2 of them are:
Cavagna (843-689 9935) and Sherwood (800-323 3870, 716- 433 3891) Sherwood LPG Products Catalog
I suppose they must use Rochester (float valve) too: Rochester Gauges
The files from both companies have nice drawings and everything you wanted to know about LPG gauges, valves, ....and a lot more.
We asked Worthington if people who have 20Lbs aluminium tank
could not use OPD valves made for 30LBs steel, as they both have a 4.8 tube.
He said he didn't know why not. But, it was unclear to him why they listed different numbers: for 20Lbs aluminium # 295177 and 30Lbs steel # 294013. (didn't say what make)
My cynical opinion is: so they can charge more for the aluminium one.
BUT: Sherwood: 20Lbs alu & 30Lbs steel have same #
So, if you have a 20Lbs aluminium tank, you are in luck
: use the OPD valve for a 30Lbs steel tank.
I have found an interesting supplier of propane related stuff (not RV specific), and they give some nice links: (like Worthington, Sherwood,....) RMI Gas Equipment distributor
That's all for now.