Propane Mystery?

[dkoldman]

Ok I got question for the GPGs (Grand Propane Gods)

So today, I decide to check on my propane, preparing for a trip in 3 weeks.
My tank specifications per manual says 18 gallons and 76 lbs. I have 2019 Winnebago Sunstar 29VE.

The inside gauge LEDs read 1/3 of a tank remains.
The actual tank outside had indicator pointing straight up indicating half way full.
I am in Dallas Texas
Outside Temperature 87 degrees

So I figure why not go fill it up. I drive to a local U-haul who charges $2.99 / gallon. If someone has a better price, I will listen?

THe U-haul Manager comes out and fills it up; but it is only 4.3 gallons!!!

I asked him was he sure and he was confident it was full. So I go inside and the LED gauge is now reading Full, I go to the tank and it too is reading Full all the way to the right.

I asked the Manager how could it be because I have 18 gallon tank, and he says maybe I only have a 8 gallon tank?

The last time I purchased propane was 2/15/20. I bought 7 gallons then. I am pretty sure the LED gauge was reading Empty then; but I was NOT out of propane.

Any idea of what is going on?

RV USA confirms my specifications.
https://www.rvusa.com/rv-guide/2019-...n-29ve-tr41862

Picture of tank below, on bottom it has some specs stamped on tank case but I can't read it.

[JimOIB]

The math works out if we go by the specs - 18 gallons times 4.2 pounds per gallon of propane is roughly 76 pounds.

As far as the LED reading 1/3 - that means your tank is somewhere between 1/3 and 2/3 full. The gauge on the tank read 1/2 and that is somewhere between 1/3 and 2/3. I trust the tank gauge and use the LED as “guidance”.

So a half full tank taking on 4.3 gallons probably means you have a 40 pound tank or 9.6 gallons. (40 divided by 9.6 = 4.2 the weight of a gallon of propane.

Check the sticker on the tank - only way to be sure.

[dkoldman]

Originally Posted by jimbo12

The math works out if we go by the specs - 18 gallons times 4.2 pounds per gallon of propane is roughly 76 pounds.

As far as the LED reading 1/3 - that means your tank is somewhere between 1/3 and 2/3 full. The gauge on the tank read 1/2 and that is somewhere between 1/3 and 2/3. I trust the tank gauge and use the LED as “guidance”.

So a half full tank taking on 4.3 gallons probably means you have a 40 pound tank or 9.6 gallons. (40 divided by 9.6 = 4.2 the weight of a gallon of propane.

Check the sticker on the tank - only way to be sure.

Your data is why I pose the question. There is no sticker on the tank. The data we seek is stamped on tank but so light you can't read it especially with the paint on the tank.

Why would Winnebago say it is 18 gal / 76 lb tank if it is only half that size?

I did get some crude measurements from the tank. It is about 28" long and about 14 wide in diameter. it round rectangular cylinder.

[JimOIB]

Hmm that is about the size of a 74-76 pound tank. Did the UHaul person vent the tank when they were filling it?

We need some number off of the tank - make and model, tare weight, anything then we can tell.

[dkoldman]

Originally Posted by jimbo12

Hmm that is about the size of a 74-76 pound tank. Did the UHaul person vent the tank when they were filling it?

We need some number off of the tank - make and model, tare weight, anything then we can tell.

I want to say yes... but not certain. There was a point where propane was spewing out a little valve; so I stepped back, not up to get a closer look

I don't remember if the spill out was from tank or the hose he had?

It reminds me of how I bleed out air from my pool filter and then close the valve.

If Winnebago 's specs are right ( it is hard to believe that it could be wrong) then it means both gauges could NOT be accurate. Or something was wrong with air being added?

[The_Breeze]

Originally Posted by dkoldman

Your data is why I pose the question. There is no sticker on the tank. The data we seek is stamped on tank but so light you can't read it especially with the paint on the tank.

Why would Winnebago say it is 18 gal / 76 lb tank if it is only half that size?

I did get some crude measurements from the tank. It is about 28" long and about 14 wide in diameter. it round rectangular cylinder.

He's correct. There's a water volume number on the tank. Take 80% of that and That's your true tank capacity because the OPD (Overfill Protection Device) will stop it at 80% full. Also, always use the vent at the top of the tank while filling.

[taylorbob1]

My tank is 28” long and 12” diameter

It’s a 12.2 gal tank and holds about 9.5 gal

If my gauge shows “1/2 tank”, there’s about 4 gal remaining

[taylorbob1]

In other news...
I wish I had two 6gal tanks, side by side with the auto switch when tank one is empty
Like I did on my last travel trailer

I can pull the tank and take it in my car or truck to get filled

It’s much easier to manage

[dkoldman]

Originally Posted by The_Breeze

He's correct. There's a water volume number on the tank. Take 80% of that and That's your true tank capacity because the OPD (Overfill Protection Device) will stop it at 80% full. Also, always use the vent at the top of the tank while filling.

Really hard to read what is on tank due to paint and some rust.

But I did see 17.6 GAL if I take 80% of 17.6 I get 14.08 and I did see something else that had OD 14 ?

I beginning to think that 14 gallons is how much I can hold at the Overfill but tank size is for 17.6


So if that is true, if tank was half full, I should have been able to get 7 gallons today, but I only got 4.3 gallons? That is why I pose the question. Is it possible that U - haul filled in such a way that they only captured 4.3 gallons when maybe it was more?, or somehow air is mixed to filled the tank?

[JimOIB]

When your tank gauge reads FULL it is at the 80% level by design. You can see that on the gauge F and 80%.

The fact that you went from 1/2 to F with 4.3 gallons would lead me to believe you have a 40 pound tank, not a 76 pound. The numbers on the tank are key to the mystery.

One of 3 things are going on: 1) the RV builder put the wrong tank in...not unheard of, or 2) the float in the tank was not installed correctly, or 3) the tank gauge is faulty. I would take the gauge off and see if there is crud behind it. It is either a snap on or there are two small screws holding it on. It will come off without losing any gas from the tank.

[16ACE27]

Your propane gauge is run by a float on an arm just like a gas tank gauge. They are easy to bend when installing. Consequently, a gas tank that holds 11 gallons may take anywhere from 3 to 8 gallons when it "reads" half full. It's not an exact measurement and knowing what you actually have in the tank vs what the gauge says comes from experience.

But you get a whole lot less experience filling a MH propane tank so it takes a lot longer to "dial it in".

The LEDs run from a magnetic sensor on the physical gauge which induces additional error.

Just like your tank level indicators, take it as a ballpark reading and find something else to spend your time pondering.

[Bob Denman]

This may just be a propane tank gauge that needs a new ser of eyeglasses.
It wouldn't be the first time that a gauge was inaccurate...

[dkoldman]

Originally Posted by jimbo12

When your tank gauge reads FULL it is at the 80% level by design. You can see that on the gauge F and 80%.

The fact that you went from 1/2 to F with 4.3 gallons would lead me to believe you have a 40 pound tank, not a 76 pound. The numbers on the tank are key to the mystery.

One of 3 things are going on: 1) the RV builder put the wrong tank in...not unheard of, or 2) the float in the tank was not installed correctly, or 3) the tank gauge is faulty. I would take the gauge off and see if there is crud behind it. It is either a snap on or there are two small screws holding it on. It will come off without losing any gas from the tank.

Seeing the 17.6 gal under the tanks all but confirms that that is the pre *0% number; so I am concluding my actual capacity really is 14 gallons (80% of 17.6 GAL number I saw on tank). I can confirm that last Dec I added 10.1 gallons and it was NOT empty.

1. I will confirm tank Monday but I doubt they put in wrong tank? If it were suppose to be larger it would NOT fit. All documentation I have and online say tank capacity is (18 gal) but tank has 17.6 gal number on it.
2. Float may be an issue, I will have them check before it goes off warranty.
3. Tank gauge faulty? If it were out of warranty, I probably would check myself, it has two screws. Kind of odd because the gauge almost block your view of the gauge if that make sense I will have this added to check out with #2 above.

EDIT: the piece blocking the gauge I reference in #3 may actually be the sensor that goes to the inside RV panel on the wall? If so, the way it is installed it covers up about 1/3 of the gauge that is on the tank.

[dkoldman]

Originally Posted by 16ACE27

Your propane gauge is run by a float on an arm just like a gas tank gauge. They are easy to bend when installing. Consequently, a gas tank that holds 11 gallons may take anywhere from 3 to 8 gallons when it "reads" half full. It's not an exact measurement and knowing what you actually have in the tank vs what the gauge says comes from experience.

But you get a whole lot less experience filling a MH propane tank so it takes a lot longer to "dial it in".

The LEDs run from a magnetic sensor on the physical gauge which induces additional error. This explains what I was referencing above

Just like your tank level indicators, take it as a ballpark reading and find something else to spend your time pondering.

I think you are right... that basically neither of the gauges are accurate.

I am actually having a lot of fun diving into these topics one by one. Last night another poster had issue with Propane Fridge switch not going back to electric when power was restored. This morning I put mine to a thorough test. It is what made me look closer at the propane level because at point when I turn the electric off the fridge went to Red meaning error and propane did not kick on? Inside RV was saying 1/3 and I though it may have been empty? It was NOT empty because I turned on heater which worked fine. Then when I tried to the Fridge again on propane it came on so all was good.

Since I was in the RV; I thought I would fill it. I was thinking I was going to buy 12 -14 gallons , so I was shocked when it stopped at 4.3 gallons.

I will have it on the list for Dealer to look at on my next trip, but I think I will follow you advice to get more experience. The easiest way will be let it run completely empty. I can see how long that takes. Then I will get a true capacity in gallons on next fillup. I am thinking I can carry 14 gallons total.

[dkoldman]

Originally Posted by Bob Denman

This may just be a propane tank gauge that needs a new ser of eyeglasses.
It wouldn't be the first time that a gauge was inaccurate...

I really need to find that guy who hired a lawyer who said he made Thor take his brand new RV back after 6 months? I was willing to concede the metal fragments in one of the lower bay compartments, and even the sawdust in the wall panel behind the Fridge; but an inaccurate gauge

[The_Breeze]

Originally Posted by taylorbob1

In other news...
I wish I had two 6gal tanks, side by side with the auto switch when tank one is empty
Like I did on my last travel trailer

I can pull the tank and take it in my car or truck to get filled

It’s much easier to manage

I have 2-20lb that I tote in the towed and use an extend-a-stay. Have yet to use the second one. I'm probably not boon docking enough. Spent two weeks in Hungry Horse, MT on one tank. It took 2.7g to fill it back up. This Norcold is awesome. And yes, I did use the stove top too.

[JimOIB]

You're good with the tank - both dimensions and tank stamp verify that. You have a 17.9 gallon tank when filled with water or a 14.3 gallon tank when filled with propane. Your math is correct.

A half tank fill-up should have been 7.1 gallons but it only took 4.3 - a 40% difference. I usually see 20-25% difference. It is just the error induced by the mechanics of the float and magnetic sender gauge.

Do what 16ACE27 suggests and dial your system in. I keep a log of tank gauge reading and pounds to fill. I know now that if I'm running the stove and fridge that when the 1/3 idiot light turns off it is time to refill. If I'm running the furnace I watch the tank gauge and when is gets to 1/4 I refill.

[OldWEB]

If you look at your gauge, it will go past the "F" mark, "F" is only 80% of the tank capacity at a certain temperature. So "Full" is 80% of 18 gal or 14.4 gal.
But half full will still be half of the total tank capacity or 9 gal.
So when you 'filled' a half tank with 4.3 gal..... 9 + 4.3 = 13.3 I think that is pretty close to the full mark of 14.4 gal

And as was mentioned, the indicator lights are really crude....

[dkoldman]

Originally Posted by OldWEB

If you look at your gauge, it will go past the "F" mark, "F" is only 80% of the tank capacity at a certain temperature. So "Full" is 80% of 18 gal or 14.4 gal.
But half full will still be half of the total tank capacity or 9 gal.
So when you 'filled' a half tank with 4.3 gal..... 9 + 4.3 = 13.3 I think that is pretty close to the full mark of 14.4 gal

And as was mentioned, the indicator lights are really crude....

[dkoldman]

Originally Posted by OldWEB

If you look at your gauge, it will go past the "F" mark, "F" is only 80% of the tank capacity at a certain temperature. So "Full" is 80% of 18 gal or 14.4 gal.
But half full will still be half of the total tank capacity or 9 gal.
So when you 'filled' a half tank with 4.3 gal..... 9 + 4.3 = 13.3 I think that is pretty close to the full mark of 14.4 gal

And as was mentioned, the indicator lights are really crude....

Here is the proof that you are EXACTLY right

I went out and took the below picture. It is about 15 degrees cooler this morning than yesterday when filing with propane.

The gauge is actually on 3/4 full. Which based on what I have just learned is 75% of the full 18 gallons; which means 13.5 gallons is in tank now per this gauge.

Then I compare with you exact quote....

So when you 'filled' a half tank with 4.3 gal..... 9 + 4.3 = 13.3 I think that is pretty close to the full mark of 14.4 gal

The 13.3 gal is almost exactly equal to the 13.5 gal the gauge is actually reading which implies an accurate gauge

Note: This would mean that yesterday that while U haul filled it (meaning to the point where it bleed out), it is not 100% full (or at the 80% mark of Full). At the same time the LED indicator inside is reading is FULL