Problems when RVing in extreme heat

[DonTom]

Hi Don. Thank you for the invite. We passed thru there a few days ago. We were at a state park near to there. I think it was hidden springs campground in Humboldt state park. We are now in crescent city but will be crossing into Oregon today. Slowly working our way to Victoria BC where we will wait out the heat wave and then head inland to the Okanagan.

Enjoy your trip Don.

That was close, maybe someday we can get our timing to be right.

BTW, I saw a 2020 Tesla M3 here the other day. It looked like it was towed here, but I didn't ask. Is that a possibility with a 2020 M3? It was very close behind a parked motorhome.

BTW, I was up in that area last year.

-Don- Redcrest, CA

 

[RayIN]

I keep hearing this thing about the RV needs to be level for the fridge to work. I have never experienced this phenomenon. Our little TT is parked in the backyard, not level, and the fridge is working fine.

Norcold states "level" for their products is, 3° side-to-side, 6° front-to-back or less, as looking at the fridge door. Dometic says if the RV is level enough to live in comfortably, it is likely level enough for proper fridge operation.

 

[RayIN]

In "George", the Norcold only works properly if the RV is reasonably leveled. I guess my driveway is too inclined.

The problem with operating out of level limits is, the cooling unit is slowly being damaged, which is permanently cumulative.
All this is explained in detail on the Fridge Defend website. I used to be skeptical, but through the last 20 years all that information has proved to be correct and accurate.

 

[DonTom]

I was just reading this.

"Is it OK to Leave Propane Tank Outside in Summer?"​

Some of the more interesting notes:

They should not be allowed to get above 120F/49C.

" When the propane tank is exposed to high temperatures, the increased pressure can affect the efficiency of your propane-burning appliances due to irregularities in the gas flow."
And this:
"How does the propane gauge work? " Much like a gas gauge.

The normal PSI range inside the tank is 100 to 200 PSI.

There is no doubt that my propane tank is MUCH higher than 120F on very hot days with the engine heat blowing on it from the underside. Cannot even touch it. It's too hot to touch.

Anyway, I couldn't find anything about why my propane gauge would pin, or if the extra high pressure/ high heat could turn the propane back to a solid liquid.

But I wonder if this is a safety issue, sure sounds like it. Should these motorhomes be recalled? But what would the fix be, to redesign the motorhome by moving the propane tank more to the rear?

-Don- Redcrest, CA

 

[ex-member]

That was close, maybe someday we can get our timing to be right.

BTW, I saw a 2020 Tesla M3 here the other day. It looked like it was towed here, but I didn't ask. Is that a possibility with a 2020 M3? It was very close behind a parked motorhome.

BTW, I was up in that area last year.

-Don- Redcrest, CA

Yah someday Don.

Not sure on the model 3 being towed. Maybe there is a cheat. Don’t know.

 

[DonTom]

Found what I was looking for here.

" As temperatures rise, liquids become less dense and expand. "

So the gauge will read extra high when very hot because the propane level expands.

-Don- Redcrest, CA

 

[DonTom]

I just got done installing my Newentor Weather Station in this motorhome. I measure for four areas, that is the max this unit can do with its one internal and three external temp sensors.

I have a remote sensor one (shown on screen left, 83.4 F) on top the the propane tank, using Velcro. I have sensor two in an outside compartment in the rear to compare to, on the opposite side of this motorhome. That side has the sun on it right now and shows as 93.3F on the screen (not shown below, switches automatically between the three).

The third one, sensor three, I have mounted on top of the hitch mount stuff, to get a true outside temperature (80.1 F right now).

I will soon see how much the propane compartment increases in temp after the engine has been running for a while.

That may not be for a couple of weeks, I enjoy this place and I will probably want to stay here for another week or two. I will be swimming in the Eel River tomorrow. Great hikes in the Redwoods, with trails to places to swim, but all a few miles away from this RV park.

-Don- Redcrest, CA

 

[Gary RV_Wizard]

Found what I was looking for here.

" As temperatures rise, liquids become less dense and expand. "

So the gauge will read extra high when very hot because the propane level expands.

-Don- Redcrest, CA

That's correct only if the surface pressure remains constant. In a sealed tank, any expansion or evaporation of the liquid causes a corresponding increase in the pressure in the tank above the liquid, which in turn limits the expansion of the liquid. In essence, the higher pressure increases the liquid's boiling point. Hard to guess how much the liquid volume actually changed.

It appears in your tank the liquid LP volume increases enough to push the float gauge high and also submerge the vapor pickup tube, flooding the regulator with liquid propane. Whether that happens with a tiny volume change or a large one is academic - it happened!

 

[DonTom]

That's correct only if the surface pressure remains constant. In a sealed tank, any expansion or evaporation of the liquid causes a corresponding increase in the pressure in the tank above the liquid, which in turn limits the expansion of the liquid. In essence, the higher pressure increases the liquid's boiling point. Hard to guess how much the liquid volume actually changed.

It appears in your tank the liquid LP volume increases enough to push the float gauge high and also submerge the vapor pickup tube, flooding the regulator with liquid propane. Whether that happens with a tiny volume change or a large one is academic - it happened!

Before I left my Auburn house, the HOUSE propane was at 20%, a few days ago. Checked right on the tank.

I just now checked it on my Smartphone Mopekia App.

It says it is at 100% on the Mopeka app. I have never seen that before, not even when the tank was "full" to around 80%. The Mopeka app in the past has always been within around two percent of what the tank gauge says.

It is around 100F there right now at 2000 hrs. It says here, tomorrow will be 108F in Auburn, CA.

I assumed in this motorhome the engine heat was adding to it and perhaps it would otherwise still give me liquid propane at 100F, but the tank was much hotter than that because of the engine heat.

Could I have such an issue at my Auburn house with the tank at 100F? I don't recall this happening before, and my Mopekia app has always been fairly accurate in the past.

-Don- Redcrest, CA

 

[Lou Schneider]

Before I left my Auburn house, the HOUSE propane was at 20%, a few days ago. Checked right on the tank.

I just now checked it on my Smartphone Mopekia App.

It says it is at 100% on the Mopeka app. I have never seen that before, not even when the tank was "full" to around 80%. The Mopeka app in the past has always been within around two percent of what the tank gauge says.

It is around 100F there right now at 2000 hrs. It says here, tomorrow will be 108F in Auburn, CA.

I assumed in this motorhome the engine heat was adding to it and perhaps it would otherwise still give me liquid propane at 100F, but the tank was much hotter than that because of the engine heat.

Could I have such an issue at my Auburn house with the tank at 100F? I don't recall this happening before, and my Mopekia app has always been fairly accurate in the past.

-Don- Redcrest, CA

Mopeka works by bouncing ultrasound through the liquid in the tank and measuring the time it takes for the pulse to return from the liquid/gas boundary layer, then displaying the liquid level it detected. Like radar except using sound waves.

It may well be at high temperatures and a low liquid level the liquid/gas boundary is too low or indistinct for the Mopeka to sense. In that case it will measure the bounce from the top edge of the tank.

 

[DonTom]

It may well be at high temperatures and a low liquid level the liquid/gas boundary is too low or indistinct for the Mopeka to sense. In that case it will measure the bounce from the top edge of the tank.

Interesting. I never would have thought of such a possibility.

-Don- Redcrest, CA

 

[Gary RV_Wizard]

I've lived in south Florida for half of my life and summer temperatures like these aren't so rare. Ambient is usually below 100 (94-96 typical) but anything in the sun would get burning hot. One of my homes had a 250 gallon LP tank that sat in full sun all day long and I don't recall any issues with that. Nor with the ubiquitous 20# BBQ tanks.

 

[DonTom]

I've lived in south Florida for half of my life and summer temperatures like these aren't so rare. Ambient is usually below 100 (94-96 typical) but anything in the sun would get burning hot. One of my homes had a 250 gallon LP tank that sat in full sun all day long and I don't recall any issues with that. Nor with the ubiquitous 20# BBQ tanks.

Yeah, I assume when I get home, back to Auburn, if still hot, the gauge on the tank will still show around 20%, with my Mopeka app showing 100%. I think Lou figured out what was happening. IOW, a Mopeka issue, not a propane issue at all.

-Don- Redcrest, CA

 

[Wasillaguy]

Seems to me you may have a defective over-pressure valve (very dangerous). As liquid level rises, so does pressure. Should have bled off vapor.
I've seen personally what was described earlier regarding tanks painted a dark color, only on a much larger scale.

 

[DonTom]

Seems to me you may have a defective over-pressure valve (very dangerous).

I think it did let some loose, as I could smell a little propane when I checked the tank in Dunnigan, CA and now the gauge is showing my level as 75% instead of the original 80%.

-Don- Redcrest, CA

 

[RayIN]

I was just reading this.

"Is it OK to Leave Propane Tank Outside in Summer?"​

Some of the more interesting notes:

They should not be allowed to get above 120F/49C.

" When the propane tank is exposed to high temperatures, the increased pressure can affect the efficiency of your propane-burning appliances due to irregularities in the gas flow."
And this:
"How does the propane gauge work? " Much like a gas gauge.

The normal PSI range inside the tank is 100 to 200 PSI.

There is no doubt that my propane tank is MUCH higher than 120F on very hot days with the engine heat blowing on it from the underside. Cannot even touch it. It's too hot to touch.

Anyway, I couldn't find anything about why my propane gauge would pin, or if the extra high pressure/ high heat could turn the propane back to a solid liquid.

But I wonder if this is a safety issue, sure sounds like it. Should these motorhomes be recalled? But what would the fix be, to redesign the motorhome by moving the propane tank more to the rear?

-Don- Redcrest, CA

Wow!!! Does that mean I must bring my 1,000G propane tank inside with the air conditioning when the steel is 120°F???
Whomever wrote that blog has a lot to learn; then again, "ignorance is bliss" it's said.

 

[DonTom]

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

I think it means the relief valve could open and that can be a danger in some situations. Such as you don't want to be smoking near it when that happens. And I think it is only referring to the portable propane tanks. IAC, I agree it could have been made clearer. Many propane tanks are not so portable and easy to move.

And in this RV with engine heat blowing on my tank on 110F days. No doubt that is way over 120 F. And I wonder how safe that is.

-Don- Redcrest, CA

 

[John From Detroit]

I've lived in south Florida for half of my life and summer temperatures like these aren't so rare. Ambient is usually below 100 (94-96 typical) but anything in the sun would get burning hot. One of my homes had a 250 gallon LP tank that sat in full sun all day long and I don't recall any issues with that. Nor with the ubiquitous 20# BBQ tanks.

While I agree Temps like this are not rare in S. FL. But at the END of JULY. not the start. IT's going to get Hotter before it cools down for the End of January.

 

[RayIN]

Oops, my mistake, didn't mean to quote you.

I think it means the relief valve could open and that can be a danger in some situations. Such as you don't want to be smoking near it when that happens. And I think it is only referring to the portable propane tanks. IAC, I agree it could have been made clearer. Many propane tanks are not so portable and easy to move.

And in this RV with engine heat blowing on my tank on 110F days. No doubt that is way over 120 F. And I wonder how safe that is.

-Don- Redcrest, CA

I couldn't find a icon for sarcastic comments, sorry it came across as serious.
LP cylinders and tanks are designed with high temperatures in mind; when they are heated enough to vent excess vapor pressure it will be in short bursts just enough to return to maximum safe pressure.
Any bleed-off/venting of LP into the air from a 20 or 30j# cylinder is not dangerous, by the time the vapor mixes with the air while exiting the vent, it's well below flash-point mixture of 2-10% by volume.

 

[DonTom]

it's well below flash-point mixture of 2-10% by volume.

That is nice to know! IYO, is there any danger with engine heat getting to my propane tank?

Also, IMO, it seems kinda dumb to have the stock house batteries right above the propane tank. But at least they are not below. I do not propane is heavier than air.

And boats use natural gas because it is lighter than air.

-Don- Redcrest, CA