Following a recent fillup of my 2007 Class A MH propane tank, the serviceman rather casually (I thought) informed me that I had a "bad" automatic shut-off valve that should be replaced. I'd appreciate someone knowledgeable informing me whether this is an item I can easily find at a good RV parts store, and if it's a part the average MH owner/handyman can replace. Thanks, in advance, for all help offered.
Automatic Shut-off Valve on Class A MH Propane Tank
- Thread starter hugh37
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Mavarick
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Not quite sure of an auto shut off but some do have what they call a "stop-fill" which I think is what he is talking about. You can only fill your tank to 80% capacity then either your overflow or this "stop-fill" come into play. They are usually easy to get to so a local propane dealer should be able to identify and replace it if it is bad. Any repairs require some careful leak testing as a mistake could become very serious at the most inopportune time. IMO if your not completely sure a local dealer is money well spent when it comes to propane.
DAN L
Well-known member
these systems rarely fail unless there is a leak. certainly not on a 2007 moho. there is an overflow valve that the serviceman should have opened and closed. maybe that is leaking. make sure the valve is closed. it usually doesn't have a handle on it. it doesn't have to be tightly closed with a wrench, but pliers may help. use soapy water and check for bubbles.
maybe this info will you to understand the system.
i would not just go out and purchase anything on a serviceman's sayso.
http://www.propane101.com/index.htm
maybe this info will you to understand the system.
i would not just go out and purchase anything on a serviceman's sayso.
http://www.propane101.com/index.htm
Gary RV_Wizard
Site Team
LP fuel jockeys are rarely well-versed in tank repair, so I wouldn't be too alarmed. As the others have said, it's not clear what an "automatic shutoff" is either, since that is not a standard technical term for LP tanks and that alone makes the advice suspect.
Your tank does have an overfill protection device (OPD) inside the tank which could be termed an "auto shutoff" from the perspective of filling the tank, but it would take some thorough testing to know if it was bad. That would be a rare failure in any case. Replacement, if needed, is best done by a trained LP professional at an LP gas shop (not an RV dealer). The OPD stops the filling process at approximately the 80% level, which is the "safe" fill point mandated by the National Fire Code (NFP). It is not exact, though.
Dan mentioned the overflow port. Standard practice is to open the overflow port and pump LP into the tank via the big filler port until liquid LP begins to bubble out of the overflow. Then close the overflow port. The OPD device may or may not auto-close the filler port before that happens, but usually not.
If the fuel jockey was relying on the OPD to stop the fill process, he may have concluded it wasn't working if LP bubbled out of the overflow. That's an erroneous conclusion.
Your tank does have an overfill protection device (OPD) inside the tank which could be termed an "auto shutoff" from the perspective of filling the tank, but it would take some thorough testing to know if it was bad. That would be a rare failure in any case. Replacement, if needed, is best done by a trained LP professional at an LP gas shop (not an RV dealer). The OPD stops the filling process at approximately the 80% level, which is the "safe" fill point mandated by the National Fire Code (NFP). It is not exact, though.
Dan mentioned the overflow port. Standard practice is to open the overflow port and pump LP into the tank via the big filler port until liquid LP begins to bubble out of the overflow. Then close the overflow port. The OPD device may or may not auto-close the filler port before that happens, but usually not.
If the fuel jockey was relying on the OPD to stop the fill process, he may have concluded it wasn't working if LP bubbled out of the overflow. That's an erroneous conclusion.
Utclmjmpr
Well-known member
In my experience its the opposite,,it tightens my jaws when the auto stop on the filling equipment stops the fill before the "overflow port" indicates full. I want to know its FULL before I leave.>>>Dan
John From Detroit
Well-known member
Portable tanks are supposed to stop the fill automatically at 80%, however with RV tanks the techinician has to pay attention as that may not always be the case.. Epically on older rigs.
Most pump jockeys are well trained in portable tanks, if, that is, they are well trained at all.
Most pump jockeys are well trained in portable tanks, if, that is, they are well trained at all.
Gary RV_Wizard
Site Team
If they were trained at all, they would have heard the injunction that the OPD valve is NOT to be relied upon to stop fuel delivery. It is a safety valve, not a filler convenience mechanism.
The overflow (bleeder) port may or may not be exactly in sync with the OPD float shutoff. Things like the levelness of the tank/vehicle can affect that, so the overfow bleeder may begin to flow before the OPD shuts off, or in other circumstances the OPD may close first. It's not a real precision thing..
The overflow (bleeder) port may or may not be exactly in sync with the OPD float shutoff. Things like the levelness of the tank/vehicle can affect that, so the overfow bleeder may begin to flow before the OPD shuts off, or in other circumstances the OPD may close first. It's not a real precision thing..
supermod38
Well-known member
when he say's "automatic shut off" maybe he is talking about the shut off connected to the lp leak detector!
just a thought.,
bob
just a thought.,
bob
Sweet Hitchhiker
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Was he talking about the "ball check valve" that he was connected to with his hose. I have seen these pop back and not seal. We had a plastic rod to push it in when the hose was disconnected and it would then seal. This can happen on any age motor home.hugh37 said:
To all who responded, many thanks...and I'm sorry for not replying before now. For info, I've just had the same serviceman out to "top off "my tank and was able to inquire precisely what he meant by "automatic shutoff valve". It became obvious that he was referring to the overfill protection device (OPD), which he said is supposed to stop the fill at approximately 80%...before the LP escapes from the overfill port. He showed me that, again, the "automatic shutoff valve" did not work, and pointed to the LP escaping from the overfill port. He "cautioned" me to make certain that all future servicing people first open the overfill port, since the "automatic shutoff valve" cannot be expected to function properly until it is replaced. He informed me that this "automatic" valve is located inside the tank at the large filler port, and that the tank must be completely empty prior to replacing it. Again, thanks to all for your valuable input.
RLSharp
Well-known member
I am curious how many people have motor homes with propane tanks that spit propane from the overfill port before the OPD device activates.
I know that mine does, when the motor home is level, and I have never had a propane attendant tell me that my OPD was faulty. I have filled a completely empty tank and the amount of propane necessary to fill it came within 0.1 gal of what I calculated the empty tank should hold.
I would much rather rely on the overfill port than the OPD. I think it would be a mistake to file a motor home tank and not open the overfill port. If the OPD failed, you could overfill the tank and create a potentially dangerous situation.
BTW, I always watch while my tank is being filled and I try to level the motor home with the jacks before filling.
Richard
I know that mine does, when the motor home is level, and I have never had a propane attendant tell me that my OPD was faulty. I have filled a completely empty tank and the amount of propane necessary to fill it came within 0.1 gal of what I calculated the empty tank should hold.
I would much rather rely on the overfill port than the OPD. I think it would be a mistake to file a motor home tank and not open the overfill port. If the OPD failed, you could overfill the tank and create a potentially dangerous situation.
BTW, I always watch while my tank is being filled and I try to level the motor home with the jacks before filling.
Richard
I'm not sure our 1997 propane tank even has an OPD. Every time we get it filled, the attendant opens the overfill port and shuts off the fill when liquid comes out of the port. None have ever mentioned the presence, or lack of, an OPD.
supermod38
Well-known member
Ned said:
ditto on my 95
Mavarick
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Yea, my OPD is called a stop fill according to my manual and is on a 2003. Didn't know they weren't required before 02.
Gary RV_Wizard
Site Team
Ned,
ASME-certified fixed LP tanks have been required to have OPD valves since 1988. DOT certified portable LP bottles have been required to have OPDs only since 2002. However, there is an exception to the DOT OPD requirement for horizontal LP bottlesmanufactured be fore 1998. The terms tank and bottle are generally used to distinguish fixed from portable LP containers.
There is nothing I have seen in the OPD specification that says it has to close before the overflow port dribbles liquid.
ASME-certified fixed LP tanks have been required to have OPD valves since 1988. DOT certified portable LP bottles have been required to have OPDs only since 2002. However, there is an exception to the DOT OPD requirement for horizontal LP bottlesmanufactured be fore 1998. The terms tank and bottle are generally used to distinguish fixed from portable LP containers.
There is nothing I have seen in the OPD specification that says it has to close before the overflow port dribbles liquid.
So, does the exception mean my tank isn't required to have an OPD, or just that it doesn't work until after the overflow port exudes liquid?
The site I quoted just says "LP devices" and doesn't distinguish between tanks and bottles.
I'm confused ???
The site I quoted just says "LP devices" and doesn't distinguish between tanks and bottles.
I'm confused ???
