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Discussion Starter #1
I was using a standard 15lb propane tank when all the sudden it just wouldn't light my stove for more than 2 seconds. I thought it weird because I didnt think it was low. Sure enough, I took it out and it was about half full. I tested it on a grill and same thing, it couldn't hold a flame for longer than 2 seconds. So I popped in a spare propane tank that was maybe 1/8th full of propane and it works fine in my campervan. Have any of you had this happen before? Is there anyway to fix the tank? I'd hate to have to just get rid of it.
 

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I suppose that one option would be to take to one of the takes your empty tank and exchanges it for a full tank. They would end up either fixing it or recycling it if not fixable.

Gary
 

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Probably just frozen. It can happen in high humidity or if you're drawing a large amount of fuel. Let it sit for a while and warm up, then try it again.
 

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Some tanks have a safety that closes if there is no back pressure or line connected. Make sure the appliance valve is off, connect the tank and try opening the tank valve very slowly.
 

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All of the above seem reasonable;

Im assuming from your description your van regulator worked with the “test tank”.

@83Grumman is correct regarding the back pressure as a safety & IIRC the regulators can also shut down if too much pressure is applied too quickly (opening up the tank valve too quickly).

but it sounds as if your tank valve is defective. Regardless I would het a new tank or exchange it as you want to eliminate the tank/valve as an issue & who wants those problems while camping

Good Luck !!
 

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Discussion Starter #6
Thanks for the responses guys. Very helpful. It's probably some sort of safety shut off, though I'm not sure why that would have happened. The propane is liquid inside so it's not frozen. I'll just go exchange it for a new one (hopefully home depot will exchange it because it's not blue rhino).
 

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I'm sure Rhino will take it -- I've exchanged tanks with them from other places.

Not that it makes much difference at this point, but Rhino only fills their exchange tanks 3/4's full.
There are some exchanges that provide the full 20 lbs.

Really irritating that Rhino gets away with this, but sometimes not a lot of choice when on the road.

Gary
 

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Thanks for the responses guys. Very helpful. It's probably some sort of safety shut off, though I'm not sure why that would have happened. The propane is liquid inside so it's not frozen. I'll just go exchange it for a new one (hopefully home depot will exchange it because it's not blue rhino).
It's not that the propane in the tank freezes, it's that when it expands, going from liquid to gas, it freezes in the line. This happens often in portable outdoor heaters. Annoying as heck and kind of counter intuitive. If it's humid the outside of the valve and the first couple inches of line will get covered in frost.
 

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Hi,
I don't see how propane could freeze in the line. It freezes at -306F and it boils at -44F.
As the propane expands in the regulator it cools, but its never going to reach -306F.

It seems like if some kind of freezing is going on, that there must be some water contamination?




Gary
 

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Hi,
I don't see how propane could freeze in the line. It freezes at -306F and it boils at -44F.
As the propane expands in the regulator it cools, but its never going to reach -306F.

It seems like if some kind of freezing is going on, that there must be some water contamination?


Hi,
I don't see how propane could freeze in the line. It freezes at -306F and it boils at -44F.
As the propane expands in the regulator it cools, but its never going to reach -306F.

It seems like if some kind of freezing is going on, that there must be some water contamination?




Gary
I think water contamination is a good answer. In several restaurants I've worked in the patio heaters would shut down and the valves would be frosty. The fix was to put a hot wet towel on the tank valve. Maybe some separation of the layers of the hose combined with water contamination? My first little buddy heater did it a couple of times and replacing the propane line fixed it.
 

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I'm sure Rhino will take it -- I've exchanged tanks with them from other places.

Not that it makes much difference at this point, but Rhino only fills their exchange tanks 3/4's full.
There are some exchanges that provide the full 20 lbs.

Really irritating that Rhino gets away with this, but sometimes not a lot of choice when on the road.

Gary
All the Blue Rhino tanks that I have seen are actually 15 lbs and not your standard 20 lbs tanks. This makes an exchange more expensive if you give up your 20 lbs tank. Fixed price refills are also more expensive than most measured fills.
Valves go bad, had a couple that would not flow in the past. Luckily they were older tanks.
 

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Hi,
My understanding is that Rhino exchanges standard 20 lb tanks, but they only fill them to 15 lbs.

One of our local tank exchange services does a full 20 lb fill up on their exchange tanks and they say this in their advertising:

Article on 15 lb refills in 20 lb tanks...

Gary
 

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The propane is liquid inside so it's not frozen.
It's not that the propane is frozen (solid) - rather, if the propane is too cold, the vapor pressure will be equal to atmospheric pressure, and there won't be any pressure to push the gas out. But, if that were the case, the tank would be very cold to the touch (well below 0C) and it would be pretty obvious.
If it's the safety valve, you can work around that by turning off the appliance(s), then open the tank, and wait a minute or two. That will allow the lines to come up to pressure, and once the valve detects pressure on the lines it should open.
You can also try tapping the tank with a mallet (or just a chunk of wood) to see if the valve is stuck.
 

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This gives the propane tank vapor pressure at various temperatures...

As you say, it would have to be really really cold for the propane not to generate enough pressure to work -- at -30F, the vapor pressure is still 6.8 psi.

Gary
 

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@dtwigs

Did you get your problem resolved?

If so can you report back your solution & in your estimate what the problem was?
 

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Most likely it's your OPD valve a new one can be bought for $20 there are U-tubes for more info.
I think so also !

I have purchased many 20lb tanks from Costco over the years @ $36 Canadian including the $20 OPD valve. If one does that then the tank is year stamped & IIRC good for 10 years?

Fill Station People check the age of the tank prior to filling them - or they are suppose to.
 

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Discussion Starter #18
@dtwigs

Did you get your problem resolved?

If so can you report back your solution & in your estimate what the problem was?
Sorry my area has been over taken by wild fires so haven't looked into it in a while. I swapped the tank out with another and it works fine, but I havent been able to bring the faulty one to the propane guys.
 

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Hi Wow,
Is that true? I think the vapor pressure of a liquid is 0 when it exactly equals atmospheric pressure -- that is it just starts to boil with air over it.

That's -44F for propane, so at -30F it would have the +6.8 psi above atmospheric?

"The vapor pressure of any substance increases non-linearly with temperature according to the Clausius–Clapeyron relation. The atmospheric pressure boiling point of a liquid (also known as the normal boiling point) is the temperature at which the vapor pressure equals the ambient atmospheric pressure. With any incremental increase in that temperature, the vapor pressure becomes sufficient to overcome atmospheric pressure and lift the liquid to form vapor bubbles inside the bulk of the substance. Bubble formation deeper in the liquid requires a higher temperature due to the higher fluid pressure, because fluid pressure increases above the atmospheric pressure as the depth increases. More important at shallow depths is the higher temperature required to start bubble formation. The surface t"ension of the bubble wall leads to an overpressure in the very small, initial bubbles. "

Or, maybe I'm wrong?

Gary
 
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