Overfilling Prevention Device
The OPD or "Overfilling Prevention Device" is designed to automatically fill a cylinder
to 80% of it's volume and contains an auto-stop device to prevent overfilling. The L.P. Gas Bureau
in the State of New Mexico, has adopted this ruling effective January 1, 2000 for all cylinders
from 4 pounds (1 gallon) to 40 pounds (10 gallons). If you have an old style cylinder valve
and your cylinder certification is due (the law requires that cylinders be visually requalified
and marked 12 years after manufacturing and every 5 years after requalification.) You will be
required to retrofit your existing cylinder with a new OPD valve. You can recognize the new valves
by the markings on the service handle and the shape of the new handle. The markings will state
that the valve is an OPD on the top and the handle is a triangular shape.
The shut off system consists of a float and seat assembly, as seen in the picture here on the
left. When the liquid level of the cylinder reaches 80% of the volume, the float assembly
closes the seat assembly and the valve shuts off the flow of propane into the cylinder. Some of
the more recent valves have a float assembly enclosed in a tube that extends into the
cylinder to the proper depth (As shown in the picture above). The OPD valve comes equipped with the "left hand" POL thread
to accomodate older equipment currently in use.
To locate the date of manufacture on your cylinder, remove the cylinder from the appliance
and clean the safety collar that surrounds the service valve. (as seen in the picture to
the left). Locate the stamped markings on the collar. Verify that the cylinder is approved
by the Department of Transportation. (The cylinder will have the DOT-4BA240 stamp in the
collar to verify that the cylinder does meet all requirements). Many cylinders are manufactured
outside the United States of America. Any cylinder that does not have the
approved stamping on the collar can not be requalified or refilled. The date will be stamped next
to all of the information on the collar. The date of manufacture will be indicated by the
month/year. Example: (2-88 = February, 1988) Any cylinder manufactured before 1988 will
need requalification. Effective April 1, 2002, all cylinders from 4 to 40 pounds will be
required to have the OPD valve installed for service, regardless of the date of manufacture.
For more information regarding the OPD valves, please contact the office located in your
community.