Propane consumption

[SheriP]

We are on the maiden voyage with our 26sab Cougar. We had both LP tanks filled prior to leaving. They took 13.9 gallons so pretty sure they got filled all the way. We got to our campsite around 3pm with temps in the 50s. It went down to the 30s during the night and 40s today. In the past 24 hours we've gone through both tanks although the green dot says there's gas in them but no furnace. Any suggestions?

[nied]

I doubt that you are out of propane unless you have a exterior leak. The propane in your tanks will power the furnace for about 40 hours of continuous operation. Sounds like your furnace has a problem.

[Canonman]

There might be an air bubble in the line. Does the stove work? Water heater?
If so there is gas in the tanks.
Are you using battery power or connected to shore power? Low battery will cause the furnace to not light if the fan can't run.
Using up both tanks in 24 hrs doesn't sound right to me.

[JRTJH]

Your tanks may not be empty, the propane may not be "gassing" or you may have a frozen regulator or supply hose. Try warming up your tanks and regulator to see if they will start flowing again.

Doing some math, you can pretty much see how long your 7 gallon tank will last. There are about 92,000 BTU's in a gallon of propane. The furnace is a 35,000 BTU input device. So, you can get about 2.5 hours of furnace operation on a gallon of propane. doing the math, 7 gallons x 2.5 hours per gallon = roughly 17.5 hours. So each tank of propane will run the furnace (CONTINUOUSLY) for about 18hours. Now, the furnace doesn't run 24/7, so you'll get more than a day of use from a tank of propane. How much more depends directly on the temperature outside and the thermostat setting inside.... Most people get 3-4 days on a tank in below freezing (but above zero) temps.

Try warming up your tanks and your regulator, see if it helps. The only way to know for sure how much propane you have is to weigh the tanks.

[sourdough]

Going through both tanks in 24 hours didn't happen without a leak IMO, or mechanical malfunction. I've spent almost 3 days and nights at near zero before one tank ran out much less two. OP needs to dig into this a little more.

[rhagfo]

13.9 gallos is two full tanks, a truly totally drained cylinder will hold up to 7.1 gallons, so you are only short .3 gallon at most.

[bobbecky]

Another possibility is, when you removed the cylinders to have them filled, and then reinstalled the cylinders on your trailer, you may have opened the valves too fast and set the excess flow valves in the pigtails. Try turning off the valves on both cylinders, remove both pigtails from the valves, then reinstall the pigtails to the valves, and finally, open the valves VERY SLOWLY. Then try your furnace again. Hopefully this will fix your problem.

[Ruko]

Does your stove work? If so you are getting propane.

[FlyingAroundRV]

Something else to check:
Do you have an outside cooker? If so, does it have a quick disconnect? If so, it probably has a separate shutoff valve in the line near the disconnect fitting. Make sure that is off.
The quick disconnect fittings on my trailer look the same as what is on my compressor and those types of fittings are notorious for leaking.
Ask me how I know!

[Wing-in-it]

what is your thermostat set at?

If you have it set high you’ll definitely burn more propane.

I run mine at 68* and run an electric fireplace to offset propane use.

[RagingRobert]

Interesting to know the issue. My guess is a faulty furnace part. The roar of these furnaces do like propane mind you. I wish they could run on electric as well like the HW tank. Also remember they do have that recall on "Atwood" models regarding shut down because of wire contact with an exhaust tube.

[chuckster57]

The recall is a Keystone issue not an Atwood issue. It involves the way the wiring was routed.

[RagingRobert]

It's an Atwood furnace that has wires touching it's exhaust pipe. Either a bad design or the space it limited. Regardless, it can cause the furnace to shut down.

[bobbecky]

Originally Posted by Ruko

Does your stove work? If so you are getting propane.

On these rigs, even if you get enough propane to make the burners on the stove work, there may not be enough gas to make the furnace work. The furnace uses a lot more gas.

[JRTJH]

Originally Posted by bobbecky

On these rigs, even if you get enough propane to make the burners on the stove work, there may not be enough gas to make the furnace work. The furnace uses a lot more gas.

That's true. The typical stovetop burner is a 5,000 BTU device. The furnace input is 35,000 BTU. So, the furnace uses 7 times the amount of propane as a stovetop burner. The furnace will probably light and operate on about 2/3 normal consumption (a guess not provable fact) but anything less would likely not be enough propane to keep the flame detector closed.

[SheriP]

Thanks to all for your input and insight. I think it was an air bubble. Around 10pm the furnace kicked on and is working fine now. Merry Christmas all!

[Bamabox]

Originally Posted by SheriP

Thanks to all for your input and insight. I think it was an air bubble. Around 10pm the furnace kicked on and is working fine now. Merry Christmas all!

If you ever want to see how much propane is in your tanks, just pour some hot water down the side of the tank. Usually you can see a line, but if not just run your hand down the tank. Empty=hot, cooler=propane.

[pdaniel]

Brother in law went through a tank overnight in his fiver. His pigtail was not properly seated. On the other hand, I am parked in southern Utah with overnight temps in the 20-30s. I use a combination of electric heat and propane and use on the average of 1.3 gallons per day in a 2017 Cougar 30RLI.