LP tank size

[rangerjean]

The manufacture states that my 2018 Sonoma has two 20# LP tanks. Does that mean gallons? On the tanks themselves it says 8.5. I am unsure what these numbers mean. At any rate it wasn't enough for a 4 day trip and we ran out with just minimal use. Can I add larger tanks?

[pianotuna]

rangerjean,

That would be an inverter (i.e. 12 volt DC to 120 volt AC)

Once my water heater has reached full temperature, it will cycle every 4 hours and runs for about 15 minutes. On the other side of the coin, if I turn it off after the first cycle there is enough warm water for hand washing and dishes for the day. That saves quite a bit of propane.

[rangerjean]

Pianotuna, I miss-spoke about the C-Pap my husband wired in a (not sure if it is a converter or inverter...electrically challenged here)system to run his machine...not propane. Yes we did keep the water heater on for the first couple of days then I turned it off until I needed it. I do think as was mentioned here that the dealer did not fill these tanks as he said he did.
My husband has a pretty good understanding about the purging process, I am just learning about some of these things.
Thank you for help

[SDcampowneroper]

Please take a lesson about propane. Wikipedia is a great educator. Then Go to your local propane supplier at a bulk station, not at a dispenser, , ask for a lesson in safety, capacity.
NFTA 1158 is the go to

[Old-Biscuit]

New propane cylinders are shipped either with air pressure (100#) or are shipped with a vacuum in them.

Ones shipped with vacuum do NOT need to be purged.....they can be directly filled with liquid propane

Ones shipped with air pressure MUST be purged with propane vapor 4-5 times to remove the air then can be filled with liquid propane

4 days usage...Two 20# cylinders
Either you have a leak or they were NOT properly filled


A real propane vendor (bulk supplier) can properly purge them and then fill

[ktmrfs]

wanderingbob wrote:
The dealer did not fill them ! Most of us will go all summer on two twenties

Not us. we go through mutiple 30# tanks over the summer. but then we camp a lot.

But still I've never used a 30# tank in 4 days, even in the fall or early spring with the furnace running. I suspect the OP tanks weren't anywhere near full to start with.

[pianotuna]

Hi,

Welcome to the forums!


How were you running a c-pap from propane?

Did you leave the water heater on 24/7?

[campinginthewoo]

20# is gas grill size my TT has 2 30# l.p. tanks and I use one at a time and it takes me quite a long time to empty. I don't camp much after November so not using furnace so it's mainly hot water heater and a little bit of stove and fridge while driving to campground.i know that some rv's use smaller tanks

[rangerjean]

wow, you guys are so knowledgeable. Thank you so much for this information. I never heard about purging the tanks. When we picked up the new trailer from the dealer the tanks had been filled. How can we tell if they were purged or can we get it done after the fact?

[wanderingbob]

The dealer did not fill them ! Most of us will go all summer on two twenties

[mobeewan]

On the cylinder collar there will be a number with the letters TW in front of it. That is the tare weight of the cylinder which is the empty weight.

A 20 lb propane cylinder will have a TW of between 17.5 and 18.5 lbs. 20 lbs of propane is 4.7 gallons. A full cylinder will weigh around 38 lbs.

A 30 lb propane cylinder will have a TW of about 25.5 lbs. 30 lbs of propane is about 7.1 gallons. A full cylinder will weigh around 55.5 lbs.

[donn0128]

8.5? Who knows, probably some mfg ID. More than likely the dealer added a couple of gallons of gas to check systems. Take them to a true propane dealer, have them purged and filled. Commonly called 5 gallon tanks is the norm on trailers. Rarely 7 gallon tanks will be installed.
Heck, with our old trailers two tanks would last us all summer.

[time2roll]

No actually a 20 pound tank holds 20 pounds of propane.
Gallon of liquid propane weighs 4.2 pounds.

No idea on the 8.5 but post a pic including all the markings. Could be the empty weight but that seems light.

[rangerjean]

Yes this was our first trip, We only had a fridge one oven use, a C-Pap machine and hot water heater. What does the 8.5 number on the tank mean?

[downtheroad]

Light use and only 4 days with two 20# tanks doesn't sound right.
My bet is that they weren't full. Is this the first time you have used these tanks? Possibly they were not "purged" and filled properly.