Reply
 
Thread Tools Display Modes
Old 07-10-2013, 05:49 PM   #1
Love My Sunseeker
 
DXSMac's Avatar
 
Join Date: Dec 2007
Location: Pacific Northwest
Posts: 788
Bleeding off propane before high elevations

I have noticed propane expands at higher elevations. The guage reads "more" at higher elevations. So, if you fill a propane tank at lower elevation, knowing you are going to higher elevation (6,000 feet or more), should you "bleed off" the propane somehow, by staying somewhere and using everything on propane?

I'm kind of following that. Or is this one of passionate 50/50 things, arguments for and arguments against don't cancel each other out? (Like wheel covers on wheels......)
__________________

__________________
JJ only, my cat went to Rainbow Bridge July 2015

I love my Sunseeker, when I'm on a trip I don't wanna go home!!!"

Total days camping each year: AS MUCH AS POSSIBLE!
DXSMac is offline   Reply With Quote
Old 07-10-2013, 05:54 PM   #2
Senior Member
 
Join Date: Jul 2012
Posts: 1,258
No need to worry, as the pressure change is not that great.
__________________

__________________
bakken is offline   Reply With Quote
Old 07-10-2013, 06:14 PM   #3
Site Team - Lou
 
Herk7769's Avatar
 
Join Date: Oct 2009
Location: South Eastern PA
Posts: 21,169
The new tanks have over fill prevention devices and if filled correctly you will never over pressure them.

Propane OPD - Overfill Prevention Device Cylinder Valves
__________________

Lou and Laura with Bella - German Short Hair Pointer
2008 GMC Sierra 2500HD Crewcab SB Allison Duramax
2010 Flagstaff 8526RLWS - Superglide 3300
HAM CALLSIGN - KC3FFW
Herk7769 is offline   Reply With Quote
Old 07-10-2013, 06:43 PM   #4
Mod free 5er
 
Join Date: Mar 2008
Location: Concord, NC
Posts: 24,215
Atmospheric pressure decreases as altitude increases. Air Pressure and Altitude above Sea Level
__________________
OldCoot is offline   Reply With Quote
Old 07-10-2013, 07:18 PM   #5
Site Team - Lou
 
Herk7769's Avatar
 
Join Date: Oct 2009
Location: South Eastern PA
Posts: 21,169
Quote:
Originally Posted by OldCoot View Post
Atmospheric pressure decreases as altitude increases. Air Pressure and Altitude above Sea Level
This is, of course, true. However the tank is a closed system. It only responds to temperature variations and not pressure fluctuations.

While it is also true that ambient temperature decreases as you rise in altitude, (2.5 - 4 degrees cooler per 1,000 feet of pressure altitude - Does The Temperature Drop As You Increase Altitude? | F.A.Q. | Seattle News, Weather, Sports, Breaking News | KOMO News), the OFPD ensures there is sufficient expansion space. If the OFPD is defeated, you could over pressurize the tank but not by going UP. You would have to go down where it is "hotter" to increase pressure inside the tank.

Get the tank hot enough and the tank's pressure will drop to zero when it explodes.
__________________

Lou and Laura with Bella - German Short Hair Pointer
2008 GMC Sierra 2500HD Crewcab SB Allison Duramax
2010 Flagstaff 8526RLWS - Superglide 3300
HAM CALLSIGN - KC3FFW
Herk7769 is offline   Reply With Quote
Old 07-10-2013, 08:00 PM   #6
Old Enough to Know Better
 
gasman6674's Avatar
 
Join Date: Feb 2012
Location: Greenwood, In
Posts: 462
If the tank is properly filled to the 80% level there is plenty of room for expansion. OPD (overfill protection device) valves that are required on all 20# thru 40# cylinders and all permanent vapor RV tanks will not allow the tank to be filled past 80% usually they trip well before that level. Of course they are mechanical and can fail so if you suspect it weight the tank. Take the tare weight of the cylinder that is stamped on the collar (ex TW 18 ) and deduct from the total weight EX total wt 38# - 18#tw = 20# gas.
FYI Propane weighs 4.24 pounds per gallon so a full 20# cylinder will hold approx. 5 gallons
__________________
Jim & Debbie England
Do you have Gas? 2015 F350 6.2L CCLB DRW 4.30 axle. 2012 Yellowstone Ridgeline 34RLT Fifth Wheel
gasman6674 is offline   Reply With Quote
Old 07-11-2013, 01:13 AM   #7
Love My Sunseeker
 
DXSMac's Avatar
 
Join Date: Dec 2007
Location: Pacific Northwest
Posts: 788
Well, I had a tank filled to 80% once, then when I went to a higher elevation, the needle shot WAY PAST THE FULL mark. I was concerned!
__________________
JJ only, my cat went to Rainbow Bridge July 2015

I love my Sunseeker, when I'm on a trip I don't wanna go home!!!"

Total days camping each year: AS MUCH AS POSSIBLE!
DXSMac is offline   Reply With Quote
Old 07-11-2013, 09:03 AM   #8
Senior Member
 
RPAspey's Avatar
 
Join Date: Jul 2008
Location: central PA
Posts: 973
if your gauge uses PRESSURE to measure how full the tank is, then the change in elevation WILL cause an errant reading. The gauge measures tank pressure relative to atmospheric pressure. Generally a cheap gauge will only be reasonably accurate if you are at the same elevation as the factory. At lower elevations, the gauge would read lower due to higher air pressure. Of course if you are higher in elevation, the gauge would read higher due to lower air pressure.

If you have a float type level gauge, then altitude would not make a difference. I don't think campers would have this kind due to DOT regulations.
__________________
2000 Cherokee 29BH with 6V batteries, LED lights & 400 watts of solar power, flipped axles and raised. 2007 Tundra 5.7L DC-LB with lots of mods. C-co, 8/158th AVN Maint.
RPAspey is offline   Reply With Quote
Old 07-11-2013, 09:34 AM   #9
Senior Member
 
w4drr's Avatar
 
Join Date: Aug 2012
Location: Roanoke, VA
Posts: 233
A pressure gauge is meaningless with regard to how much propane is in the tank. The propane is a liquid, and the pressure in the tank will remain constant, give or take due to temperature, until all the liquid propane is gone. The only true measure of how much propane is in the tank is the weight, which was previously mentioned. The only real purpose of a propane pressure gauge is to enrich those who make and sell them.

Bob
__________________
Bob & Doris
Roanoke, VA
2009 Toyota Tundra CrewMax 4x4 - 5.7L - 6 Speed Auto - 4.30:1
2013 Rockwood HW296
w4drr is offline   Reply With Quote
Old 07-11-2013, 09:38 AM   #10
Old Enough to Know Better
 
gasman6674's Avatar
 
Join Date: Feb 2012
Location: Greenwood, In
Posts: 462
RPAspey
There are not any rules that I am aware of that prohibit a float gauge in a cylinder. Manchester and Worhington both offer a tank with a gauge. You can also retrofit existing 20 and 30# tanks with a new OPD gauge valve so you can have an accurate level indication.
Attached Thumbnails
Click image for larger version

Name:	OPDTankPath no label.jpg
Views:	94
Size:	51.0 KB
ID:	35073  
__________________

__________________
Jim & Debbie England
Do you have Gas? 2015 F350 6.2L CCLB DRW 4.30 axle. 2012 Yellowstone Ridgeline 34RLT Fifth Wheel
gasman6674 is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



» Virginia Campgrounds

Reviews provided by




ForestRiverForums.com is not in any way associated with Forest River, Inc. or its associated RV manufacturing divisions.


Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -5. The time now is 04:07 PM.