Propane leaking down

[Kristian]

I have a 2019 vengeance toy hauler and I noticed that when I shut the propane off it doesn't hold pressure like my old campers have done .
Took it to the dealership for some warranty work and told them about the propane leaking down

Work was completed and went and picked up unit and they told me it was normal for that to happen.

Does anyone else have this issue and was told it was normal?

Takes about 4 hours to leak down when gas is shut off.

[AlaskaErik]

Both my trailers leak down over time. I've been told it's normal.

[5picker]

All of my R/Vs through the years have experienced this 'leak-down' over a period of several weeks. (not 4 hours as you mentioned!)

I have tested every one of them for external leaks and have found none.

I believe the LP in the lines simply slowly escapes past the non-electrical activated shut-off valves of the water heater/furnace/refrigerator.

Just remember to purge the LP lines by lighting the stove after an extended shut-down of the LP system.

[Reverse_snowbird]

You're talking about propane leaking in the trailer lines, not the tank itself, right?

I never thought about it, but every time we took our rig out and turned on the propane, we'd have to light the stove to bleed the lines and get the flowing to the different appliances. So, I guess the lines bleeding out over time is normal. Not sure what that time frame would be.

[boondocking]

You must have a slight leak, 4 hour bleed down is not normal.

[Scrapper]

Four hours is about right. You have to realize that the rubber in those hoses connected to your tank and regulator are not completely impermeable to gas. That is the main reason metal pipes and tubing is used in buildings.

FWIW, For those who have a refrigerator and/or stove in a slide-out be sure to check the lp hose under the slide on a regular basis. Pay particular attention to the area of hose that bends/flexes when the slide goes in/out.

Go ahead, ask me how I know.

[boondocking]

I must have a very special propane system.
I can turn on the tanks after being turned off for 2-3 days and my propane appliances fire right up immediately.

[Scrapper]

Originally Posted by boondocking

I must have a very special propane system.
I can turn on the tanks after being turned off for 2-3 days and my propane appliances fire right up immediately.

They usually do as not all the lp leaks out, it just equalizes to the surrounding air pressure. Once the air has been bled out during the first usage, you should never have to bleed it out again unless the lp system has been open to the air.

Most of the time if you change one of the high pressure hoses from a tank to the regulator you will hardly notice it. If you change the regulator or the low pressure hose from the regulator to the main LP pipe or you remove both tanks from the RV at the same time you will have to bleed the air. I had to change the LP hose to my kitchen slide-out which opened the system, when done I had to bleed the air out.

[Kristian]

Like I said the last 4 trailers I have had never did this . My trailer usually stays at my property 4 hours away from my house it stays plugged in with refrigerator stocked and left on I keep the gas on so if the power goes out I won't come up to a mess. I am up there every weekend .

[Chuck_S]

Leakdown could happen but I've not experienced it.

I turn the propane valves On at the start of the season and turn then Off at the end. If there were leaks I'd expect to drain the tanks. Only time I've run out of gas is when the local squirrels decided to see what the hoses tastes like and made small punctures in both. Same procedure with my back deck gas grill.

But I know I should turn the valves Off between trips and grilling.

-- Chuck

[The Evil Twin]

I would isolate all the appliances first. Turn the gas of at their respective regulators. Then pressurize the lines. If it still leaks down then its in the line fittings. If not, it is at an appliance. The regulator at the LP tank(s) is also a common leak area. Gas leak spray every fitting you can reach. I prefer the real leak spray over soapy water.
A couple hours seems fast.

[nomad297]

Originally Posted by Scrapper

Four hours is about right. You have to realize that the rubber in those hoses connected to your tank and regulator are not completely impermeable to gas. That is the main reason metal pipes and tubing is used in buildings.

Propane and natural gas “disappear” from the inside of any type of pipe over time by osmosis — the gas slowly seeps through the wall of the pipe — any type of pipe — and is replaced by air. Every fall I have numerous calls where the customers think that their gas fireplaces have quit working when, in fact, all that is wrong is that since they turned off the gas to the fireplace at a valve several feet away from the fireplace when they were done using it the previous spring, the gas has since left the pipe by osmosis and was replaced with air. So, they try lighting the fireplace pilot and give up because the air doesn’t light after several minutes of pushing in the pilot button and clicking the piezo igniter — their fingers get tired and they just assume their gas fireplace is broken. All I do when I get there is bleed out the air in the line and light the pilot. They are always frustrated that they have to pay me for this and insist that there must be a leak somewhere. I have given up explaining to customers how this happens and just tell them to Google it. It never fails, though — I am always back at the same customers’ homes the next year to do the same thing.

Four hours, though, is much too short of a time for gas to be replaced by air by osmosis, so there is a leak somewhere. It may be too small to locate using soapy water due to the low pressure of an RV’s gas system. You may have to either use a combustible gas detector or introduce high pressure air into the system so a leak will show using soapy water. But if you are going to use high pressure air, you need to isolate all of your appliances and the propane tanks/bottles so you don’t destroy their gas control valves, regulators, etc. So, if you have a leak beyond wherever you isolated your appliances/tanks/bottles, you won’t be able to find it, and many gas leaks can be at the appliance, itself. Most of the gas leaks that I find in homes/buildings are at the regulators. I attribute this to the regulators not being pressure tested since they are isolated from the high pressure during a standard gas system test. If you are going to do this yourself, the best way to do it will be to use a combustible gas detector. You can rent them.

Bruce

[nomad297]

Originally Posted by The Evil Twin

I prefer the real leak spray over soapy water.

Me too. I pay a premium for what most people think is just Dawn and water. I only use soap and water after I go out to my truck and find that my plastic bottle of liquid gas leak detector has split and leaked all over my tools and covered the bottom of my tool bin with slime. The stuff I buy works much better than dish soap and water.

Bruce

[AlaskaErik]

Originally Posted by The Evil Twin

I would isolate all the appliances first. Turn the gas of at their respective regulators. Then pressurize the lines. If it still leaks down then its in the line fittings. If not, it is at an appliance. The regulator at the LP tank(s) is also a common leak area. Gas leak spray every fitting you can reach. I prefer the real leak spray over soapy water.
A couple hours seems fast.

You can get a gas sniffer for less than $35 on Amazon.

[Scrapper]

Originally Posted by nomad297

Four hours, though, is much too short of a time for gas to be replaced by air by osmosis, so there is a leak somewhere.


Bruce

You are forgetting to address the fact that RV's use rubber or plastic hoses to connect to the tanks and regulator. Depending on how long those hoses are can speed up the leakage.


Take my TT for instance, 2x 18" high pressure hoses from the tanks to the regulator, a 4' 3/8 ID hose from the regulator to the 28' black pipe supply running down the length of the trailer to just behind the rear axle, a 8' 3/8 ID hose from the right side of the TT to the manifold near the furnace and wh, and a 16' 3/8 ID hose from the end of the black pipe across the TT to the fridge and stove in the slide-out. The cracks seen in one of the attached pictures is where the 16 foot hose bent 180 degrees when the slide-out was retracted.

[The Evil Twin]

Originally Posted by AlaskaErik

You can get a gas sniffer for less than $35 on Amazon.

True, but I question their accuracy. Numerous times I have only been able to find a low pressure leak the old fashioned way. With non combustible gasses (refrigerant for example) I can boost pressure to 100 psi with nitrogen and sniffers work ok. At least the professional ones do. LPG systems that are in well ventilated areas can be increased to working pressures also. Still, I have had some leaks that could only be found with bubbles.