2007 Winnebago Journey Propane Capacity and Gauge Accuracy

[tim myers]

My 2007 Journey has a 31 gallon fixed propane tank. I know it does not hold 31 gallons of propane, and looking for something on the tank itself that might list the usable capacity, found 27.9 stamped on the tag. That would be approx 90% of 31, and sounds high. The full port valve starts venting when the gauge shows 85%, this level also matches the inside tank level as 100%. I am a worry wart and start getting nervous anytime the tank gauge gets bellow 1/2, and have been trying to figure out what 1/2 tank represents in gallons left. I know these gauges are not very accurate, but it keeps my mind active. Yesterday the tank mounted gauge showed me a about 5/16 full took 11.6 gallons to get it to 3/4 full. Wondering how much propane was left int he tank.

 

[Morich]

Way too complex for me to ever consider working out the correct answer!
One biggie is the temperature! From experience with portable propane on industrial equipment, it is not uncommon to get a tank that has been filled to the correct amount and then while using it, the gas expands and pops off when the sun comes out!
Basic idea is that the liquid propane is there because it is under pressure and as the propane gas is used, more will turn from liquid to gas until there is no more liquid. So when the gauge is reading liquid, there is still some that has not gassed off yet as it is only reading the liquid!
How long that will last before you begin running out of the gas as well is tricky as it depends on so many things like what you are doing with the gas! Furnaces and water heaters tend to take lots more gas than a single burner on the stove!
Like the info I read about how long your money will last in retirement?

 

[creativepart]

A 31-gallon total capacity propane tank holds 24.8 gallons of propane when filled to the standard 80% safety level. The fill vent on your Journey is calibrated to start venting at ~80%. You can find this 80% number in your Operator's Manual. You are correct that 27.9 gallon number on the tank is a 90% rate.

 

[Waterbug]

Propane tanks, wether RV, home service or barbecue are usually never loaded over 80%., it just allows for external temperatures changes. This fact makes "full tank" readings confusing. Just never let your propane drop level below 25%; and get on with your life.

 

[tim myers]

Thanks CP and WA, for your insight. I knew all that but recent refills had me doubting my math. So I thought it was a good time to ask and you came through for me. The simple truth is that I think my tank gauge is reading about 5% low. When the 80% valve started spewing the gauge only read 75%. The amount of propane to get me from about 5/16th tank to full wasn't enough based on the math.

So thank you, and I have learned that I get more accurate answers from this group than the general IRV2 group. All of you are amazing.

 

[RayIN]

The 31G comes from total water capacity. Since the tank must have vapor space, 80% LP capacity is the maximum. ½ full will then be 12.4G of LP.
For comparison, a 20# cylinder will hold approx. 4.5G LP @ 80%.