LP Tank Question

Hi All,

Please can anyone tell me if there are any differences with the propane tank for an RV as opposed to one for a BBQ grill?  I have a 20 lb tank in my truck camper and I'm wondering if I can get a spare from a regular hardware store or if I need to go to an RV place.

Thanks so much,
Dianne

They are identical.

Fantastic!  Thanks so much for the quick reply!!!!

The tanks on your RV may be larger capacity, but the connections are standard.  So is the gas pressure regulator used on the RV.

Thanks.  I just googled what the regulator looks like and I do have one of those in the compartment.  I'll ensure I use it with the replacement tank.  I also ordered a gauge to watch the fill level.  Last year I ran out of propane and had to walk the tank to the fill station.  I have a truck camper and I didn't want to break camp for it.  I promised myself I wouldn't let that happen again!  I have a 20 lb tank according to the paperwork on the camper.

Thanks again!

Just don't get your hopes up too high that a propane gauge is going to give you very accurate readings, most of them are marginal at best.

xrated said:

Just don't get your hopes up too high that a propane gauge is going to give you very accurate readings, most of them are marginal at best.

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You might just weigh the tank on your bathroom or other scale. The empty weight is stamped on the collar of the tank and labeled T or Tare.

diannenaughton said:

I also ordered a gauge to watch the fill level.  Last year I ran out of propane and had to walk the tank to the fill station.

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A gauge that screws into the tank outlet measures the propane pressure, not how much propane is in the tank.  Propane isn't a compressed gas, it's stored in liquid form with a vapor bubble on top.  As you draw out vapor, the liquid boils into more vapor to replace what you took out.

Pressure gauges are all but useless because the tank pressure is determined by the tank's temperature, not how much propane is inside.  A pressure gauge will read "full" until all of the liquid propane has evaporated into vapor, then the pressure will fall like a rock.  Liquid propane is 270 times more dense than vapor, so when the liquid is gone the tank is effectively empty.

The kind of gauge you need for accurate level measurement is a replacement valve with a liquid level gauge built into it.  It has a float that extends into the tank and shows the level of the liquid propane, accurately showing how propane you have left.

Another way to tell how much liquid propane remains in the tank is to pour a cup of hot water down the side of the tank, then run you hand down the side.  Liquid propane is a much better heat sink than vapor, so you'll feel a distinct point where the metal stays cool in spite of the hot water flowing down it  That's the level of the liquid propane.  The tank level strips work using this principle, changing color where there's vapor when you pour hot water over it, staying dark where liquid propane drains away the heat.

Wow, all great information!!! Thank you so much!!!

I tried one of those strips last year but it didn't change color anywhere. 

I'm going to go searching for one of those gauges that measures the liquid.  That sounds like the best option but until I find one, I'll use the hot water trick!

I really appreciate the help.  I'm not even going to open the gauge I bought that screws in.  I'll return it and put the $25 toward the better one!

Thanks again!

I think what I'm looking for should be like this:

http://www.outbackers.com/forums/index.php?showtopic=27647

But I'm having trouble finding it.

What do you think of either of these? I'm guessing the one with the magnets goes by weight and the other temperature?

https://www.amazon.com/AP-Products-024-1002-Propane-Indicator/dp/B01C5RQKJA/ref=pd_day0_hl_263_3?_encoding=UTF8&pd_rd_i=B01C5RQKJA&pd_rd_r=819b874d-5f86-11e8-bf8e-eb3c744d8fe4&pd_rd_w=VF4hR&pd_rd_wg=kBL0F&pf_rd_i=desktop-dp-sims&pf_rd_m=ATVPDKIKX0DER&pf_rd_p=4014010564823900592&pf_rd_r=3BMAG5WE8GSQYMX5CST0&pf_rd_s=desktop-dp-sims&pf_rd_t=40701&psc=1&refRID=3BMAG5WE8GSQYMX5CST0

https://www.amazon.com/GasWatch-Bluetooth-Propane-level-Indicator-Smartphone/dp/B0165U9L5I/ref=sr_1_51_sspa?s=lawn-garden&ie=UTF8&qid=1527189401&sr=1-51-spons&keywords=propane+tank+gauge&psc=1


Thanks again!

I think I found it!!!

https://www.kingsupply.com/20-lb-OPD-Tank-Valve-with-Build-In-Propane-Level-p/opd-20wg.htm

At a good price too!

I don't know anything about the first two devices, but the valve and gauge from King Supply should work.

Note it's only for a 20 lb. tank, it will read wrong with taller or shorter tanks.

Changing the valve assembly is not a do-it-yourself job.  Take the tank to a propane distributor that services tanks.  The tank has to be completely drained of propane, then after the new valve and gauge are installed the tank has to be purged of air before refilling it.

Ok that makes sense!  I wondered about the installation part of it so I'm really happy you told me.  I'll try my local rv place. They seem to handle a wide array of service / repairs.

This is really important to me to be able to properly gauge this so I'm ok with spending the money needed to do it right.

Thanks again!

New 20 lb LP cylinders can be bought complete with a mechanical level gauge built into the valve for about $30.


https://www.menards.com/main/heating-cooling/propane-tanks/steel-20-lb-empty-propane-cylinder-with-gauge/308551/p-1444447741181.htm

I'll try my local rv place.

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Unless your RV place is an authorized and licensed propane supplier, don't do that. Find an propane dealer who is so licensed or do as suggested by NY_Dutch.

Hi a really easy way to tell the level of your propane is to take a pot of warm water and
pour it do the side of the tank. Then run your hand do the path of the water. Where
the tank feels cold that will be your approx level of propane left.

I'll try my local rv place. They seem to handle a wide array of service / repairs.

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Not a good choice. They are probably not trained LP gas techs, plus they will be very expensive. Go to an LP gas service center - every area has them.

I'd just buy a scale and set the tank, on it permanently. Accuracy will probably drift over time but it should stay close enough for years.

Ernie

Re Tanks Ax others have sait the tanks on a TT are basically identical to a BBQ. May be bigger (30 pounds instead of 20 as an example) but otherwise identical and you can indeed swap 'em.

Re gauges
There are two types (well 3 not that I think of it) possibly a 4th I will describe

Pressure gauges. Often with just a RED/Green dial  They tell you "Yes there is liquid propane in the tank" or "You just ran out" If there is a quarter cup of liquid left. they are green. The only thing that will move them towards EMPTY is a cold snap. Yup they are better thermometers than propane gauges.

Of course you know you are out of propane cuuse the furnace does not furnace and you are freezing yoru... Parts... Off.

They are useful as  leak detectors however (I'll let others explain)

THe next type is a liquid crystal strip you attach to the tank, EIther peal and stick or magnetic.

You then, using propane from THAT TANK, put a pan of water on to boil (Tea kettle is best) then dump the voiling water over the strip.  It will change color.  and become TWO colors. the point where the color changes is where you find LIQUID in the tank (avove that is gas) If you get only one color.. REFILL TIME (unless you just dide)

Next is a scale. many variations on this but they make one that goes under the tank, the problem here is when you lock down the tank, you disable it.

In theory you could use a sonic sensor or other type of sensor to detect right through the metal (my dad used to do this with 100 pounders. he'd "Tunk" the tank and listen to the echo. He was very good at figuring out how much was left.. Me.. Not so much,)

YOu can buy a tank with a float type gauge. once you learn it these are acually rather good.

Tanks used on Motor homes are different, and often have a float gauge.

If you get a 2nd tank then you could probably do without a gauge. When you switch to the 2nd tank, get the empty one filled next time you are out. I have 30 lb tanks. A tank lasts me about 4 or 5 weeks with full time use. So you should get 3 weeks from a 20 lb.

Just don?t do what I did the other day. For some reason I was thinking I had filled the tank not in use. When I tried to light the stove one morning I found out I had no propane. I had to make a quick trip into town to get a tank filled. A senior moment I guess ?