Problems when RVing in extreme heat

[RayIN]

Not much danger from heat, 465°F is auto-ignition temperature- and then only if the vapor is within that percentage span; it requires an ignition source = open spark.
LP in liquid form cannot burn, only when in vapor form.

An aside; nothing liquid or solid actually burns, what burns is when a material gets hot enough to vaporize, the vapors are what actually burns.
For instance, you can extinguish a lit match in gasoline if you are quick enough putting the match into the liquid.
Since we're not Myth-Busters we'll not attempt that, right!

 

[DonTom]

Not much danger from heat, 465°F is auto-ignition temperature- and then only if the vapor is within that percentage span; it requires an ignition source = open spark.
LP in liquid form cannot burn, only when in vapor form.

That is nice to know!

But I keep on reading stuff like this:

"Keep your small, portable tanks away from extreme heat. Don’t place your tanks in places that can heat up, like the trunk of a car. Store them out of direct sunlight and keep them away from open flames.
So to sum it all up, unless your propane tank is exposed to extreme heat or fire, it won’t explode."

That seems to say the heat can make it explode.

-Don- Redcrest, CA

 

[John From Detroit]

Wow!!! Does that mean I must bring my 1,000G propane tank inside with the air conditioning when the steel is 120°F???

When I read the line you were commenting on.. That was my first thought as well.

 

[RayIN]

That is nice to know!

But I keep on reading stuff like this:

"Keep your small, portable tanks away from extreme heat. Don’t place your tanks in places that can heat up, like the trunk of a car. Store them out of direct sunlight and keep them away from open flames.
So to sum it all up, unless your propane tank is exposed to extreme heat or fire, it won’t explode."

That seems to say the heat can make it explode.

-Don- Redcrest, CA

Bullet #5 is accurate, as is the subsequent part about a small cylinder in an automobile heating up to the point the over-pressure device opens and vents LP vapor(or liquid if the cylinder is laying on its side).
The key word is "inside". This is why virtually all state DOT regulations require portable LP cylinders to be secured upright.
IMO the greater danger is the plastic gasoline tank with an explosive fuel with the same range of explosive limits.

 

[DonTom]

Now I have some numbers and other info. When it was 103°F/39.5°C on the drive back to Auburn, near Roseville, CA, the temp sensor on the top of my propane tank showed it was at 133.3°F/56°C. The two other remote sensors were near the ambient temperature all showing within a few degrees of ~103°F.

When I got back to Auburn, I checked the gauge on the propane tank. I discovered some fine print on the gauge that shows in very small digits past the normal 80% full. It is marked in fine print as "85%" and "90%" above the normal "full"( 80%). When I got back here, it was pinned hard past the 90%. Two hours later, still pinned and looked the same. The tank was still very warm to the touch.

I just now checked again, almost 3 hours after I got to Auburn. Now shows as around 88%. No longer pinned but still extra high. The tank is still a little warm to the touch.

AFAIK, my refrigerator worked fine all the way back to Auburn. I heard no alarm from the refrigerator but there is no guarantee I would hear it while driving if the alarm came and gone.

I didn't bother to test the genny or the stove. I assume the stove would have worked fine. The genny, perhaps for a while until it gets extra hot in there and then the vapor lock. I don't really need to know. All I need to know is that it will be rather useless if needed to run the A/Cs when extra hot, just how long I can run it could vary a bit.

-Don- Auburn, CA

 

[old RV guy]

Now I have some numbers and other info. When it was 103°F/39.5°C on the drive back to Auburn, near Roseville, CA, the temp sensor on the top of my propane tank showed it was at 133.3°F/56°C. The two other remote sensors were near the ambient temperature all showing within a few degrees of ~103°F.

When I got back to Auburn, I checked the gauge on the propane tank. I discovered some fine print on the gauge that shows in very small digits past the normal 80% full. It is marked in fine print as "85%" and "90%" above the normal "full"( 80%). When I got back here, it was pinned hard past the 90%. Two hours later, still pinned and looked the same. The tank was still very warm to the touch.

I just now checked again, almost 3 hours after I got to Auburn. Now shows as around 88%. No longer pinned but still extra high. The tank is still a little warm to the touch.

AFAIK, my refrigerator worked fine all the way back to Auburn. I heard no alarm from the refrigerator but there is no guarantee I would hear it while driving if the alarm came and gone.

I didn't bother to test the genny or the stove. I assume the stove would have worked fine. The genny, perhaps for a while until it gets extra hot in there and then the vapor lock. I don't really need to know. All I need to know is that it will be rather useless if needed to run the A/Cs when extra hot, just how long I can run it could vary a bit.

-Don- Auburn, CA

I was running my generator under load at the storage facility a few weeks back and it shut down repeatedly. I suspected it was overheating, the ambient temp was 100°. Picked it up the other day and ran it under load all the way home ( 25 miles) and not even a hiccup. I think were I too need it while at a campsite during summer I might rig up a fan to circulate some air around it and keep the basement door open.

 

[DonTom]

I was running my generator under load at the storage facility a few weeks back and it shut down repeatedly. I suspected it was overheating, the ambient temp was 100°. Picked it up the other day and ran it under load all the way home ( 25 miles) and not even a hiccup. I think were I too need it while at a campsite during summer I might rig up a fan to circulate some air around it and keep the basement door open.

I think my genny will also work while driving, as it doesn't have the same problem as the propane tank with engine heat blowing on it.

-Don- Auburn, CA

 

[Kirk]

I think my genny will also work while driving,

It should as it most likely gets fuel from the same tank as your chassis engine. Propane powered generators as usually in lower priced diesels.

 

[DonTom]

It should as it most likely gets fuel from the same tank as your chassis engine.

I meant in the high heat. Vapor lock. The genny has its own non-cooled fuel pump, unlike the 7.3L gas engine that has the fuel pump cooled in the gasoline.

Perhaps the genny gas lines and fuel pump will be cooled enough by driving on the freeway in the 110°F heat to prevent the vapor lock.

-Don- Auburn, CA

 

[Kirk]

Perhaps the genny gas lines and fuel pump will be cooled enough by driving on the freeway in the 110°F heat to prevent the vapor lock

I have used the onboard generators of both class A RVs that we have owned while driving in hot weather. I know that there were times it was above 100°F but I'm not sure what the highest temperatures were.

 

[DonTom]

I have used the onboard generators of both class A RVs that we have owned while driving in hot weather. I know that there were times it was above 100°F but I'm not sure what the highest temperatures were

When I was in Dunnigan, CA in the 110°F heat, I noticed my refrigerator was not working on propane while at a rest stop. So I tried to start the genny and it wouldn't start. Perhaps it would have started on the freeway where the hot wind would still probably be enough to cool the genny lines and pump. But I didn't try. I had nothing in the refrigerator except for drinks at that time.

The problem with the propane tank is engine heat blows on it from underneath, so it gets even hotter when in motion. The engine heat can't get to the genny compartment.

-Don- Auburn, CA

 

[Lou Schneider]

When I was in Dunnigan, CA in the 110°F heat, I noticed my refrigerator was not working on propane while at a rest stop. So I tried to start the genny and it wouldn't start. Perhaps it would have started on the freeway where the hot wind would still probably be enough to cool the genny lines and pump. But I didn't try. I had nothing in the refrigerator except for drinks at that time.

The problem with the propane tank is engine heat blows on it from underneath, so it gets even hotter when in motion. The engine heat can't get to the genny compartment.

-Don- Auburn, CA

If the refrigerator wasn't cooling it was likely lack of airflow over the exterior coils, not the fuel source. Absorption refrigerators rely on the coils being hotter than the outside air to set up a chimney effect behind the fridge, heating the air so it rises through the roof vent and carry away the heat while drawing in cooler air from the lower vent. In hot weather there isn't enough temperature difference to maintain this airflow, the refrigerator can't get rid of it's waste heat and cooling stops.

The solution is to use a small fan to blow or suck air upwards behind the fridge. It doesn't take much airflow to restore cooling. People have used computer muffin fans, I just put a $10 clip-on fan on the opening during hot weather.

 

[DonTom]

If the refrigerator wasn't cooling it was likely lack of airflow over the exterior coils, not the fuel source.

Please read the first message of this thread.

The stove also would not work at that same time.

Also, the message on my Norcold was "NO LP". It was in alarm with that message. Soft beeps, but I cannot hear them until I stop and shut off the engine.

-Don- Auburn, CA

 

[DonTom]

And I had the genny vapor lock problem again while at Big Creek Camp. I think that is happening in the stupid carburetor, mounted inside where very hot. The fuel pump is mounted underneath, still hot there too, but probably not as hot as dead center inside the genny.

I am tempted to remove this Onan QG 5500 genny also, and use my portable EFI gennies that also can do 240 VAC at 30 amps (7.2KW continuous) for charging my motorcycle.

IMAO, Onans are pure junk with mostly 1960's technology.

-Don- Sac Pass, NV

 

[RV_Lee122]

And I had the genny vapor lock problem again while at Big Creek Camp. I think that is happening in the stupid carburetor, mounted inside where very hot. The fuel pump is mounted underneath, still hot there too, but probably not as hot as dead center inside the genny.

I am tempted to remove this Onan QG 5500 genny also, and use my portable EFI gennies that also can do 240 VAC at 30 amps (7.2KW continuous) for charging my motorcycle.

IMAO, Onans are pure junk with mostly 1960's technology.

-Don- Sac Pass, NV

Mine will vapor lock if I run it with the slide in and the sun is directly on the generator door (it has never quit when in the shade of the slide above it being out). It has done it twice, once when I was out walking the dog, came back wondering why the generator was off? It fired back up and was ok. Then it just did it again in a casino parking lot, slide in, direct sun, very hot. I was inside this time - it started to bog out and quit. Looked it up and bingo, classic vapor lock.

There is a mod you can do you re-route the fuel line / pump that apparently fixes the issue permanently

 

[DonTom]

There is a mod you can do you re-route the fuel line / pump that apparently fixes the issue permanently

I would like to hear more about that mod.

If there is vapor lock in the very hot carb, does pumping cooler gas into it help that much?

The time several days ago, it was when I used the genny for an hour or so and two hours after it being off it would not start. Another hour or so later, it started right up.

I never had my genny die after it once started, regardless of how long or how much load. Just will not start when very hot.

-Don- Sac Pass, NV

-

 

[RV_Lee122]

 

[RV_Lee122]

Also make sure its tuned for elevation, pretty simple

 

[DonTom]

Also make sure its tuned for elevation, pretty simple

Thanks, but my Onan QG5500 is quite a but different. He is showing the Onan 4K like in my Y2K RV which has never given me those type of problems, but I removed it anyway (when the starter crapped out) in favor of a couple of portable EFI gennies.

But in this 2022 rig, it is still possible to get to the fuel pump and filter, but the vapor lock could be in the carb in this thing, as it gets extra hot at its stock location. And no way to move it.

I do have my elevation adjustment at max, 5K' but it is closer to 7K' at this elevation, but is working well here anyway. I had the problem last at Big Creek on an extra hot afternoon several days ago.

-Don- Sac Pass, NV

 

[Brad Buchanan]

That is nice to know!

But I keep on reading stuff like this:

"Keep your small, portable tanks away from extreme heat. Don’t place your tanks in places that can heat up, like the trunk of a car. Store them out of direct sunlight and keep them away from open flames.
So to sum it all up, unless your propane tank is exposed to extreme heat or fire, it won’t explode."

That seems to say the heat can make it explode.

-Don- Redcrest, CA

You need to work on your reading comprehension.