LP propane bottle won't switch over to backup bottle - Problem solved... I think

Our Rig – Cyclone 2012 3010

Normally, I just use one bottle and leave the other tank blocked in – my theory was; just in case I run out – I’ll have a “backup bottle”.
In theory this works… but I found some holes in my plan.


Last year we ran out of propane and froze all nite, cause when I opened up the backup tank and swung the regulator lever over, we still didn’t get propane for our heater. DOH!
In the morning – we realized that the “backup” tank was actually full and eventually got things working after we goofed around. We thought maybe we just had air in the lines.
This week, the wife ran out of propane again…, even though she swung the Regulator valve from the normally online doorside bottle to the other backside tank.
The doorside tank was indeed empty, but the backside reserve tank was still full – yet we couldn’t get flow when we swung the regulator over. WTH?

So after looking online – I discovered there is a method to this tank madness.

You can NOT simply run empty on one tank and swing the regulator lever from an empty bottle to a spare backup bottle that was blocked in and expect it to work.

It WILL work, if BOTH bottles were ALREADY opened up and it auto switches over, but if you leave your backup bottle blocked in and it auto swings over – your outta luck when you open up the reserve tank.
The regulator must have a special valve inside that is locked up if one side of the regulator goes low pressure and the other side is still blocked in at the tank. (aka: slug valve?)
Swinging the regulator lever over will not give you a new supply of propane pressure. These regulators are meant to work with 2 bottles that were BOTH online/opened up.
I think how it works is you are supposed to use one bottle normally, (with both bottles opened up) and when it goes empty, it auto switches over and the flag goes red. Once you see the red flag, you know your main bottle is empty and you swing your lever over and you’ll have to run on the backup bottle til you fill your main bottle. Long story short – don’t let one tank depressure without having pressure on the other side of the regulator.

If you do find yourself in this pickle that I was in… behold – there is a solution.

A- You can simply move the backup/full tank over to the normally online tank spot – and it should work.
(But this is a hassle to move bottles around)

OR

B - You can block in both tanks and disconnect both hoses.
Swing the lever towards the Full Tank side
Depressure the propane lines using the stove top burners. Now both sides of the regulator will be 0 psi.
Connect the hose to the full tank, making sure that the regulator is still swung towards the Full Tank side.
Test out the system using the stove top burners – it should work now.

In general, from now on – I’m going to turn on one tank when I park, ensure my indicator goes green, then open up the back up bottle.
I’m going to leave both tanks open while I am camping and block then in when I am done. This will prevent the hassle of reseting the regulator valve if one tank goes empty.
When I spot the rig, if I find that I open up the normal tank and it’s MT… I guess I’lll have to do the depressure the lines thing.



Note: I'm thinking that the above stuff I typed out is correct... but maybe I'm way off. lol I've also read that the Cyclones DO NOT have an auto switchover LP regulator. Anyone know if my theory above is true and if the Cyclones do indeed have a auto switchover valve?


thanks for any insite.

Not sure what you mean by "blocked in."

When you point the regulator switch at the closed tank that's still full, and then slowly open the valve, gas should flow. I don't see how this is any different from taking the unit out of storage, where both tank valves are closed, and there's air in the LP lines. You can start by using either tank. Once the air is purged, everything should be fine.

When opening a tank valve, if you turn the handle too fast, the safety cut off will engage, blocking the flow of gas. Is it possible that's what's happening?

u243412 - I think Dan is on the right track here. It's happened to me more than once in the last 9 years. Sometimes, I just forget and open that valve real fast. What I have done is simulated a gas line break - so the safety kicks in and shuts the tank off internally. Oops.

"Blocked in" means the valve is closed.

I think the anti-slug valve (XS flow valve) will engage if you open up the cylinder fast, but it should bleed thru the slug valve at 10SCFH... so eventually both sides of the XS flow valve will equilibriate and things will eventually flow as the XS flow valve is reset. (assuming your not blasting the propane out the stove top and thus never letting the downstream side build pressure)
Maybe she did open the valve too fast. I wasn't there so I can't comment on that.
I do believe that the differential across the regulator is the key to whether or not the valve will swing over. Just my own opinion - not a backed up fact. (Maybe this is all due to the XS flow valve, but I still think there is some other mechinism inside the Marshall Regulator that is stuck in no man's land until the pressures across the regulator are balanced out. (as opposed to the pressures across the XS flow valve inside the cylinder hose)

I'm still tying to find the model of my regulator so I can look up the manual for it online. A guy working with me tonight swears he read about this in his Marshall manual when he replaced his regulator when he too thought he had a bum regulator. (Turns out his original regulator was actually OK)

I'm thinking when you say "blocked in", you mean the valve is closed. Depending on the type of regulator you have THIS DEVICE may be just what the doctor ordered. THIS LINK is the regulator the tank sensor works with.
If you would have switched the regulator before opening the 2nd (backup) tank, then open the valve slowly, you should have been OK. The newer style OPD valves don't like sudden loss of pressure. As Dan mentioned, they have a built in device that shuts down the flow of LP when sudden pressure loss is detected.

I'm still tying to find the model of my regulator so I can look up the manual for it online.

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U243412,

If you find technical manuals that do explain that the xs flow valve releases it's safety block automatically, please update this thread. I'm sure a lot of other owners would be interested in gaining a better understanding of how the LP system works.

Assuming that your automatic transfer regulator is working, there is no reason to leave one tank shut off or "blocked." When the tank the system is running off runs dry, the regulator will switch to the other tank and the indicator will show red. It does require you to be somewhat mindful of what you're running on propane and occasionally take a look in the propane compartment to see if the indicator has changed from green to red. Then switch the valve over to the other tank and get the empty one filled. It's not rocket science.

JohnDar said:

Assuming that your automatic transfer regulator is working, there is no reason to leave one tank shut off or "blocked." When the tank the system is running off runs dry, the regulator will switch to the other tank and the indicator will show red. It does require you to be somewhat mindful of what you're running on propane and occasionally take a look in the propane compartment to see if the indicator has changed from green to red. Then switch the valve over to the other tank and get the empty one filled. It's not rocket science.

Click to expand...

No it's not rocket science, but there seems to be hundreds of people online that have had this same experience. Most people resolve this reoccuring issue by going and buying a new regulator - possibly wasting lots of time, money and hassle. I'm just trying to save people these problems by figuring out solutions to a common problem. But you can just state the obvious and claim your superior intelligence with sarcasm. Thanks for your input.

Leaving your backup bottle blocked in is a personal choice. I know in the past, I've have a leak somewhere and lost more than one tank full of propane. Thus was my theory that even if I had a leak somewhere, I knew I had a reserve bottle that would get me through the weekend.

Ray - good point. Had the regulator been switch PRIOR to opening up the bottle, it may have worked. Eitherway, once a person has screwed up any form of sequence required, I still think depressuring everything and starting from scratch with the reg lever pointed to the full backside bottle would work to fix this problem. I have not found the manual for my reg yet, but I suspect there is a little ball bearing that gets jammed up due to a pressure differential across the reg.

Also, no one has mentioned if the Cylcone 3010's have a autoswitcher reg or not. I've read that most late model rigs with 2 cylinders probably do have a autoswitchover regulator, but I seem to remember my unit does not have that type of regulator. Just looking for an answer. Maybe when the wife brings back our RV I can look in the accompanying manual and find out for sure.

u243412 said:

No it's not rocket science, but there seems to be hundreds of people online that have had this same experience. Most people resolve this reoccuring issue by going and buying a new regulator - possibly wasting lots of time, money and hassle. I'm just trying to save people these problems by figuring out solutions to a common problem. But you can just state the obvious and claim your superior intelligence with sarcasm. Thanks for your input.

Leaving your backup bottle blocked in is a personal choice. I know in the past, I've have a leak somewhere and lost more than one tank full of propane. Thus was my theory that even if I had a leak somewhere, I knew I had a reserve bottle that would get me through the weekend.

Ray - good point. Had the regulator been switch PRIOR to opening up the bottle, it may have worked. Eitherway, once a person has screwed up any form of sequence required, I still think depressuring everything and starting from scratch with the reg lever pointed to the full backside bottle would work to fix this problem. I have not found the manual for my reg yet, but I suspect there is a little ball bearing that gets jammed up due to a pressure differential across the reg.

Also, no one has mentioned if the Cylcone 3010's have a autoswitcher reg or not. I've read that most late model rigs with 2 cylinders probably do have a autoswitchover regulator, but I seem to remember my unit does not have that type of regulator. Just looking for an answer. Maybe when the wife brings back our RV I can look in the accompanying manual and find out for sure.

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After your long-winded dissertation on propane tanks, it seemed you did not fully grasp how the auto-regulator system works. You would not have been the first person to post to that effect.

Nope, no claims of superior intelligence, just common sense and the willingness to fix problems rather than jerry-rig them. If my posts offend you, you can set up the system to automatically Ignore them. No skin off my nose if you do.

I had this problem on 1 tank and on a trip thru Albuquerque, NM a propane dealer said that he has replaced numerous hoses due to the green connector, he said there is a flow valve in it and is very sensitive to high flows, furnace and stove or furnace and HW tank use. I replaced my MEC brand connector hose(brand stamped on the green nut) for a Marshall one and never a problem since, Auto regs are hard to break, he said, but a 2cent spring in the green connector will cost you a new hose, easy to replace just measure the length and use some teflon tape or pipe dope to reinstall the new one. HL used lots of the MEC hoses

Just remember that if you have both bottle valves opened then if the auto-swith over is working properly it will automatically start drawing from the full bottle when the bottle it is drawing from becomes empty. This will happen regardless of which bottle the valve is pointed to as this is only a pointer to remind you which bottle is being used. (I think I said that right)

This link describes a small ball in the pigtail fitting that connects to the tank. When the tank valve is opened, the ball moves against a seat and restricts, doesn't shut tight, gas flow until pressure across the ball equalizes. Then the ball moves off the seat allowing full flow of gas. If there is a system leak or an appliance valve is open the ball will remain seated restricting flow.
http://www.motleyrvrepair.com/propane_safety_and_use.htm

The pointer must be turned to point to the current service tank before disconnecting the empty tank. If this is not done, gas will flow out the disconnected pigtail.
http://www.newrver.com/propaneregulator.shtml

From the linked website:

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.

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Based on what many of us have experienced, I think the highlighted statement may only apply as long as you don't open the valve too quickly. Admittedly that's just my guess. But if the quote above told the entire story, none of us would ever experience the problem that we get from opening the valve too quickly.