Acme or POL valve required for RV propane cylinders & cylinder re-certification

The Federal government prohibited the sale and use of POL valves found on older DoT type propane cylinders. (POL is an abbreviation for Prest-O-Lite, for the company that first produced the valve). These valves have the familiar female left-hand-thread in the valve and are the type most of us currently have. Cylinders with this type valve were discontinued beginning in the year 2000, and may may no longer be refilled.

The old POL valves were replaced by a new Acme type which uses a QCC (Quick Closing Coupling) connector. This connector has an external (male) right-hand thread on the valve. A pigtail hose can be connected and disconnected by hand... no wrench required. These valves also have the old-style POL internal left-hand thread, so they can be used directly in place of the old valves without modifying your RV. If you like the no-tools convenience of new style connector you may want to replace your pigtail hoses with new ones having the QCC connectors.

The new ACME or QCC valve also contains an OPD (Overfill Protection Device). So you may find them called ACME valves, OPD valves or QCC valves, depending on the supplier. The OPD feature prevents accidental overfill of the cylinder. An internal float mechanism shuts off the valve when the propane tank is 80% filled. The 20% empty space is necessary to prevent the cylinder from venting large amounts of propane when the temperature rises. (ASME type cylinders in most motorhomes have had this OPD feature for many years). The new OPD valve also contains another safety feature - it will not release gas unless the pigtail hose is properly connected, even with the valve open.

POL Valves

The old-style cylinder valve is known as a POL valve, named for the manufacturer that devised it. You tighten the connector of the regulator pigtail by turning the fitting counter-clockwise, and you usually need to use a wrench to make the connection tight enough to prevent leaks. With a POL valve, if you open it with no fitting attached, propane is freely released. That's why a plug is required to be screwed into the valve during transport of the cylinder and when it is stored or not connected to your RV. The plug is an attempt to prevent an accidental opening of the valve from creating a dangerous situation.

This valve also has a built-in bleeder valve the service technician uses to check for proper filling and a pressure relief device to prevent over pressurization of the cylinder.

ACME Valves

This valve is also known as QCC (Quick Closing Coupling) or OPD (Overfill Protection Device) The New ACME valve looks bulkier because there are external threads visible. The external threads don't necessarily require a change to the connector on the end of the regulator pigtail hose. They are compatible, as the left-hand-thread fitting on your RV regulator will screw into the internal POL threads of the new ACME valve.

However, one of the benefits of the new connector is that it is designed to be attached to the cylinder without tools. You only have to hand-tighten the connector. And, you tighten as you would normally tighten a threaded fitting, by turning it to the right (clock-wise). So at the cost of a few dollars it may be good to replace the pigtail hoses.

Propane Cylinder Re-certification

If you have an older RV you should know that according to Federal law, DoT cylinders may only be used for 12 years after their manufacture date. After that, the cylinders must be "re-certified" which provides another five years of use. The cylinders can be re-certified every five years thereafter.

Propane dispensers are legally required to look at the date stamped on the cylinder before filling it. Some dealers actually do look. We've been reminded a few times that our cylinders were about to expire. Check the date stamped on your cylinders... don't rely on your rig's model year even if the cylinders are original. It's quite possible they are a year or more older than your rig. Ours were.

Re-certification is usually done by the large bulk propane suppliers but we found one of our local RV repair shops was certified to do the job and they do it for free! Call around to see who may do it in your area.

Propane Safety Tips for RVers and Recreational Vehicles

As with all other fuels, propane should be handled with care and RV users should know what to do in case of a leak or other emergency. Propane gas has a smell like rotten eggs or boiling cabbage and is heavier than air, so when checking for leaks, be aware it can gather in low-lying areas.

Ignition of propane gas within an enclosed space can result in explosion, and it can be ignited by many sources including pilot lights, open flames, smoking materials, electric sparks, and static electricity.

More RV Propane Safety Tips:

Familiarize yourself with all safety precaution notices posted in your RV.
Identify all emergency shut-off valves and develop basic emergency procedures for everyone traveling in the RV.
If you think you smell propane, get everyone out of the unit and close the supply valve on the propane containers.
Have everyone leave the RV and get medical attention if anyone shows symptoms of carbon monoxide (CO) poisoning (headaches, nausea, dizziness, drowsiness, confusion, impaired judgment, loss of manual dexterity).
When using a propane stove or oven, open a vent or window and turn on the range hood fan to remove moisture and combustion products (which may contain CO).
Never use stove burners or ovens to heat your RV. They are designed for attended cooking only.
Don't use portable propane camping equipment in your RV (e.g. camp stoves, barbecues, lanterns, catalytic converters, radiant heaters).
Before entering a gas station, turn off all burners, pilot lights, appliances and automatic ignition devices. Turn off the vehicle engine and have everyone leave the RV before refueling.
Transport propane containers in the secured upright position.
Never use, store, or transport propane cylinders or liquid fuels in the passenger space or living area of your RV.
Don't transport or use propane containers that are damaged, show signs of corrosion, have been exposed to fire, or appear to be leaking.
When buying propane equipment, always ask if the product is certified for USA, as many products sold outside USA do not comply with USA safety standards.

For more information about RV propane safety and BC Safety Authority registered recreation vehicle shops, visit www.safetyauthority.ca or www.mvsabc.com. A propane safety brochure is also available by contacting your local BC Safety Authority office, or call toll-free 1-866-566-SAFE (7233).

What to do if you think you have a Propane leak:

Turn off Gas & Elec.
Open Windows and Compartment doors
let RV Air out until smell is gone
Take RV to a service center or you can do some checks yourself

Pinpoint the location of hazardous propane or natural gas leaks.

Pocket gas detector senses extremely low amounts of propane and natural gas. Just place the sensor within 1/2" of the potential leak. An alarm will sound and a red light will come on if gas is present. Detects propane at less than 1000 ppm, methane at less than 2000 ppm.Uses 2 AA alkaline batteries (sold separately). Handy for checking propane gas connections or gas leaks at stove, furnace or water heater in and around your RV. cost approx. $28.00

Do Not use a Flame or turn any Elec. while looking for a leak.

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