Propane Lessons - (Quartzsite, AZ)

Well, it was a pretty typical morning, except Linda woke up feeling like she had a cold coming on.

That really bummed her out since she is supposed to drive herself to Benson on Sunday and attend the gem show in Tucson a few days next week.  We weren't really sure if it was a cold or sinuses.  But whatever it was, she was determined to fight it off.  :)

Recently, we have been having propane issues.  We weren't getting anything out of one of our cylinders - the one in the compartment on the right.

Today, the cylinder on the left ran out.  Naturally, since I knew everything on the left was working, I moved the right cylinder (which I could tell was still at least half full by the weight) to the left side.  I hooked it up, turned it on, and got nothing.

Now I'm thinking it has to be the valve in that cylinder.  Linda & I discussed it, and I decided to take both tanks in to the RV Pit Stop.

When I got there, I explained my situation and they did a test on the half full cylinder.  No problem with the valve ... of course.

They filled my other cylinder and sold me two pigtails - the hoses and connectors that go from the propane cylinder to the regulator.  They insisted that the ones that come with RVs, the ones with the big green plastic "nuts" that connect to the propane cylinders, are not allowing enough propane through.  "We see it all the time" they said.

I got home and started to replace one of the pigtails.  Well, the ones they sold me didn't have the right size fitting, so that wasn't going to work.  Turns out that was a good thing.  We'll see why later.

I put the full cylinder, the "good" one, back on the left side, connected it, opened the valve, and ... nothing.  Sheesh.

I saw Robbie walking our way, so I asked for some help to troubleshoot our problem.  He and Butch and some others came over.  Robbie kept telling me that there is safety mechanism in the cylinder valves that sometimes cuts off the flow.

He took the "good" cylinder out, put it back in, connected it and turned the valve very slowly.  There was the hissing noise that I hadn't been hearing.  Propane was flowing, and Linda tested the stove and fridge.  Yep, everything was now working.

"You mean I was just turning the thing on too fast?" was my question.  "For three and a half years, I've been doing it the same way, and now I'm turning the valve too quickly?"  I had to find out exactly why it was important to turn the valve on slowly.  More on that later.

For those that aren't familiar, most fifth wheels these days have two propane cylinders.  Some, like ours, have the cylinders on opposite sides of the trailer, and some have them on the same side.

In either case, the cylinders are both connected to a two-stage regulator with an automatic "cut-over" switch.

There is a visible switch or lever that can be turned that designates either of the cylinders as the "primary" cylinder.  In the above photo, the lever is turned to the right-hand connection, making the cylinder connected to that hose the "primary".

When the primary cylinder runs out of propane, the automatic "cut-over", which is not visible, allows propane to flow from the other cylinder.  The visible switch or lever does not move - that has to be switched manually.

Okay, so there is an indicator on top of the regulator that tells if the "primary" cylinder is full or half full or empty.  If it is all green, it is full.

Half green is half full.

And all red is empty.  Remember, this is for the "primary" cylinder - the one to which the lever is pointing - only.

So, when Robbie put the full cylinder on the left side compartment and turned the lever to make that cylinder "primary", the indicator showed all green - just as it should.

We put the half full cylinder in the right compartment and turned it on slowly until we heard the hissing.  Then we turned it on all the way.  I turned the manual switch to make that cylinder the "primary" and the indicator went to half green, half red like it should.  Linda once again tested, and everything was working correctly.

Okay, problem solved.  But I wanted to understand it more.

I started my research.

I first wanted to find out how the new OPD (Overfilling Protection Device) valves on the cylinders (required since 2002) came into play.  Here is a pretty good link for that topic:  OPD Cylinder Valves on Propane101.com.

The gist of that discussion is twofold.  First, the OPD valves are designed to cut off filling of a tank at 80% full to allow for expansion.  That's been the requirement all along, but these valves ensure the requirement is met.

Second, these valves prevent the flow of propane in or out unless the cylinder is connected to an appropriate hose and connection.  Opening the valve (turning the knob) does nothing unless the cylinder is properly connected.

But this website makes it clear that the OPD valve itself is NOT the culprit in our situation.  The valve is not designed to restrict flow OUT of the cylinder once it is properly connected and in use.

Hmm.  So there must be something else.  Eventually, I found some more information.

Here is a link to the best information I could find:  Propane Safety & Use by Gary Motley, Master Certified RV Technician.

The important information to me related to the "pigtail" and the big green "nut".

"Let’s talk about a couple of safety features on these new pigtails. Both features are parts of the big green nut.

The first is a black thermal-sensitive bushing found just behind the green nut. If this bushing is ever in a fire with temperatures between 240°F and 300°F, it melts and allows the brass nipple inside the nut to move back about ¼ inch, which closes a small piston inside the cylinder valve totally shutting off the flow of propane. This innovative feature will help prevent fires or explosions.

The second new safety feature is called a “flow-limiting-device.” Its purpose is to restrict the flow of escaping gas if there is an excessive leak in the RV propane system. This second “flow-limiting-device” feature and how it works forms the core of the secret! Almost every time the cylinder valve is opened, a small ball in the center of the brass nipple (inside the green nut) is pushed forward into a brass seat. This seat doesn’t totally shut off the gas. By design, it allows a small amount of gas (by-pass flow) to go into the RV propane system. If everything in the propane system is closed and in the off position and there are no leaks, the by-pass flow builds up a back pressure. This equalizes the pressure in the ball back of the seat and allows unrestricted flow through the system. All this happens in about five seconds and the user doesn’t know it’s happening, appliances light, furnaces and water heaters run as normal.

Now lets look at the same system but with the oven control left in the pilot on position. Again the cylinder valve is opened, the ball is pushed into the seat, the by-pass flow goes through the system but this time it can’t equalize because the flow continues out through the open oven pilot. The user goes inside and starts cooking dinner. Two burners on the range top are lit and everything seems okay until the furnace comes on. At that point, the flames on the range top are drawn down and the furnace won’t ignite, everything seems starved out. The reason? We don’t have full-unrestricted cylinder flow to run our system, we only have the small by-pass flow which is far too small to feed the appliances trying to operate.

HOW TO FIX THE SITUATION: Turn off all the appliances, turn everything to the closed and off position, wait about 15 seconds. If the system is closed and tight, the back pressure builds up, equalizes and feeds unrestricted cylinder flow to the regulator for normal operation."

Now that makes sense to me!  And it describes the symptoms we had been experiencing.  :)

We were not allowing enough back pressure to build up and the little brass ball was staying in its "seat" and restricting our flow.

When we travel, we turn all the propane off.  When we arrive at a destination, we turn the propane back on before we turn on any appliances requiring propane.  The back pressure builds like it should and everything works fine.

Here, I was turning on propane while we had propane appliances turned on and the back pressure was not building up.  But we had turned off everything by the time Robbie came over to help, so it all worked perfectly when he connected the cylinder and turned on the propane.

So now I'm not convinced that turning the propane on slowly is the magic answer.  But I found several sites that say to do that, and it certainly can't hurt.  :)

Okay, so I usually leave one propane tank on and the other turned off so I know for sure when one of them is empty.  That kind of defeats the purpose of the automatic cut-over, but I didn't want to have to check the red/green indicator every day.  And if you don't check that, propane could be coming from the "secondary" cylinder.  If you're not careful, you can run out completely.

One problem with my method is we have appliances running when the one tank runs out.  I have, in the past, turned on the other tank and we've experienced the low flow problem.  I always chalked it up to cold weather or the time it took for the lines to pressurize.  Now we know.  :)

Most people leave both cylinders open and let the regulator and automatic cut-over do their job.  They check the red/green indicator often so they know when the "primary" cylinder runs out.  Then the switch the lever to the other cylinder so it is the "primary".

Three and half years on the road and we're still learning.  It certainly helps us troubleshoot our own issues when we know how things work.  :)

Linda got dressed and we hopped in the Jeep.  I took the new pigtails back and got a refund.

Then we went to the redwood sign place in town and ordered signs to hang on our rig.  We dispensed with our first set of signs long ago.

Our new sign will be ready tomorrow.  On the way back home, we made a quick stop at the Satellite Advantage in town.  Scott from Dustyfoot.com is there and I wanted to meet him.  He is a reputable mobile satellite installer that could be a good resource for the Forum.

I also checked the price of DirecTV satellite dishes.  Since Jack won't be joining us in Arches and we can't borrow his extra one while we are in the cabin, we'll have to find one somewhere.  :)

After that, we drove out beyond our campsite on Plomosa Road to some of the more scenic spots on the other side of the mountains for future reference.

Back home, I returned lots of emails and Linda got an informal beading group together.

I went out and sat with the group for awhile in afternoon during "happy hour".  As it got dark, everyone dispersed for dinner.  I took a twilight shot.

Linda was feeling better and went back out for the campfire, but I had gotten a shower and didn't want to end up needing another one from the smoke.

It was an educational day.  :)

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Comments

[Rod Ivers]

Once again, Howard, you have educated us all about things we have had trouble with in this RV life and didn't know why we were struggling so. The classic middle of the night, out to change the tank to the full one, and nothing will light right. Now we know to turn everything off before turning on the full tank's valve. So simple, but how do you know?

[Judy Schmader]

Question Howard, are you saying that you turn off both your propane tanks when traveling?? Doesn't your frig switch over to propane when traveling? We dont turn ours off when traveling.
southwestjudy

[Jerry/Carol Pearson]

This once again proves that the older we get teh smarter we get. We learn by doing. Chalk this lesson up for the chapter in your book on Propane 101. I can't wait.

[Howard]

Judy,
Yes, upon the advice of Mac the Fire Guy and others, we turn off propane completely when we travel. This is simply a safety issue in case we were to be in an accident and the propane connections or hoses would be severed.

We turn off the fridge as well. It will keep its coolness for several hours. We also have a battery operated fridge fan to assist on really warm days of travel.

[Sandra Merrikin]

Thanks for Propane 101, Howard, really enlightening!

[Ken]

Seems to me if the propane is left on while traveling, and there is an accident, the excess flow valve in the tank valve will shut things off. Even if the lines are severed somehow the leak of propane is the least of worries.
In a perfect world, the safest thing is to shut off the gas, but I submit the gasoline tanks in cars are far more likely to cause fire damage than the off chance the excess flow valves fail, in the off chance the propane serice lines are cut..

[Howard]

Ken,
The "propane off/on while traveling" debate gets lots of print on the RV forums - probably much more that it deserves.

I agree that the risk is limited, but turning the propane off while traveling just isn't that big a deal for us. We certainly haven't had any food spoil. We may have had some ice cream get a little soft on occasion, but that's not crucial. So, we turn off the propane 'cause fire experts tell us it's safer. :)

[Don and Stella Pippin]

Great job on the Propane Primer Howard. All that activity right on my doorstep and I missed it all. Thanks for digging to get the right answers. If we ever experience that condition we are forewarned.

We wish a safe journey to Linda as she makes her way back to Benson. She will be missed here on Plomosa Road. We know she will have a great time there!

[Al Viscardi]

Howard,
Knowing you and your research abilities...i'm certain you have the correct info. Last year we were having similar problems. It happened a few times where we thought a cylinder was empty but it wasn't. A neighbor where we were staying told me that when that happens i should take the cylinder out and "pound it on the ground" a few times. Well in my case this has turned out to be true. I has happened a couple of times since and each time when i pounded it on the ground it worked.
Al Viscardi

[Emery]

Thanks for the tips, Howard. This is one of those grey areas where similar symptoms can be caused by different reasons depending on the type and age of one's equipment.

Another couple of items to consider are that forgetting to switch the manual switchover lever to the full tank will sometimes allow a small leakage of gas back out of the pigtail of the empty cylinder. While not a problem as long as the empty is still properly hooked up, it can be a big risk if that tank has been pulled out and the pigtail is just hanging there. So, one should always double check to be sure that the manual switchover lever is pointing to the tank that is left hooked up before disconnecting any tank from the regulator.

The second item is more about convenience. There is a remote detector made for the typical Marshall regulator that just slips over the red/green indicator on the regulator T. It senses the position of the float and will turn on a flashing led on the remote box to let you know there is lower pressure coming from the main tank.

One place to see this remote sensor is: http://www.rvupgradestore.com/index.asp?PageAction=VIEWPROD&ProdID=1674 but I have seen them elsewhere for less money.

Since this is just a slip on installation it is very simple to install (depending on just where one would like to place the remote indicator.)

It does have one characteristic to be aware of, though. The position of the red/green indicator varies depending on how much gas pressure may be coming from the main (manually switched to) tank. When lp guzzling appliances like furnaces turn on the pressure may cause the red/green indicator to float a bit lower. Also, when it is very cold it will ride lower when gas is being used and this causes it to flash while those appliances are in use.

Just be sure when it is flashing that nothing is on that is using gas and you can believe that it has switched tanks. In warmer weather this is seldom a problem but it has been worth it for me so I have some idea just when the tanks switched over automatically. That gives me a more accurate idea of how long it has been on the full tank and how long the empty one lasted without having to go out and check it every day.