Free 7 Day Trial RV GPS App RV Trip Planner RV LIFE Campground Reviews RV Maintenance Free 7 Day Trial ×
 

Go Back   Thor Forums > Thor Tech Forums > Maintenance and Repair
Click Here to Login
Reply
 
Thread Tools Display Modes
 
Old 11-23-2021, 03:34 AM   #1
Member
 
Brand: Still Looking
State: California
Posts: 88
THOR #18162
Propane reading

2020 Thor class c outlaw

Inner panel propane reads 2/3 full. Outside bottle reads 1/3 full? One of them must be off.

__________________
Snks is offline   Reply With Quote
Old 11-23-2021, 03:46 AM   #2
Senior Member
 
Travelin' Texans's Avatar
 
Brand: Redwood
State: Texas
Posts: 1,527
THOR #3610
Quote:
Originally Posted by Snks View Post
2020 Thor class c outlaw

Inner panel propane reads 2/3 full. Outside bottle reads 1/3 full? One of them must be off.
I would tend to go by the gauge on the bottle. If the propane remote sensors are as accurate as the holding tank sensors then it's mostly useless.
__________________
Danny & Linda
Sold '13 Thor Redwood 36 FB
Traded '13 GMC Denali DRW D/A
Currently RV & truckless
Replacement undetermined
Travelin' Texans is offline   Reply With Quote
Old 11-23-2021, 03:47 AM   #3
Senior Member
 
MJC62's Avatar
 
Brand: Thor Motor Coach
Model: A.C.E. 27.2
State: Indiana
Posts: 1,194
THOR #14698
If I were to wager, I'd bet on the interior monitor being the one that is off. The sensors for the monitor in most RV's are notoriously inaccurate.
Your outside gauge reads 1/3. If it were me, I would go and have it filled and see how many gallons it takes. Then check the gauge and the monitor see where they stand.
__________________
2018 ACE 27.2
Toad 2019 Jeep Cherokee Trailhawk
Roadmaster Falcon All Terrain Towbar
Roadmaster Invisibrake
MJC62 is offline   Reply With Quote
Old 11-23-2021, 03:49 AM   #4
Senior Member
 
Brand: Thor Motor Coach
Model: Chateau 24F
State: Ohio
Posts: 1,407
THOR #16721
Quote:
Originally Posted by Snks View Post
2020 Thor class c outlaw

Inner panel propane reads 2/3 full. Outside bottle reads 1/3 full? One of them must be off.
When ours was new, the inside panel read empty when the tank was almost full. Ours was fixed under warranty and now agrees with the tank gauge. It's one of the things I haven't dug into... I think it's a resistance circuit which is fairly simple.

Until you get it resolved, trust the tank gauge. Sorry I couldn't be more helpful!

P.S. In reading another forum about this, there usually is a sending unit on the gauge with wires attached which run inside the coach to the panel. Mine is wrapped up under a cover for winter... otherwise I'd check it tomorrow...
__________________
Chateau_Nomad is offline   Reply With Quote
Old 11-23-2021, 12:36 PM   #5
Senior Member
 
Bob Nodine's Avatar
 
Brand: Thor Motor Coach
Model: Quantum JM31
State: Tennessee
Posts: 224
THOR #21926
As others have said the gauge on the tank is most likely more accurate than the LED indicator inside the coach. I am struggling with a propane/gauge problem now and digging into things have learned that there are two floats inside the tank. One is the overfill protection that will shut off the fill port when the liquid level reaches 80 % of the tank volume. The other is a float that moves a magnet as the liquid propane rises in the tank. That magnet moves the needle on the external tank gauge thru a wall that isolates the tank contents from the gauge so vapor leaks in the gauge are not a concern. The gauge needle is connected to a potentiometer thus changing the resistance of the potentiometer based on the tank liquid level. This is somewhere in the range of 50 to 150 ohms which is a low impedance. That LP level indicator inside the coach monitors the resistance change and gives a very crude indication of the propane available. Any poor connection along the wiring route from the tank to the LED indicator will affect the reading. The mechanism of the tank gauge is also prone to inaccuracy but is a far better indicator than the LED one inside the coach.

I have disconnected the internal LP level indicator and connected it to my Bluetooth SeeLevel tank gauge system that reads in percentage of full. To calibrate this system I need to get the tank full but so far have not been able to get it full. The propane dealers are all over the map on filling the tank. Since owning the RV it has only been filled to capacity twice, when new from the dealer and once by a propane distributor in West Virginia. They are suppose to open the bleed valve and stop filling when liquid propane comes out but most of them are scared and stop way before the tank is full. I thank many of them are confused by the 80% limit and think they should not fill to more than 3/4 of a tank on the gauge. Once in a while you will get a tech that will wait until the internal float stops the fill. I need to find one of those techs so I can get the tank to the FULL mark on the gauge.
__________________
Bob
2022 Quantum JM31, 2020 Chevy Sonic
Bob Nodine is offline   Reply With Quote
Old 11-23-2021, 02:30 PM   #6
Senior Member
 
Brand: Thor Motor Coach
Model: Chateau 24F
State: Ohio
Posts: 1,407
THOR #16721
The local outfit where I get my propane explained it this way - after I noticed it wasn't completely full according to the tank gauge:

"FULL" in a propane tank takes into account the expansion and internal pressure of the tank. Propane is stored as a "liquid propane gas" (LPG) which changes from a liquid to a gas before it is expelled under pressure from the tank. That conversion happens VERY quickly - as does expansion of the tank contents from external heat.

There is what's called the "80% Rule" with propane. 20% of the tank MUST be available for expansion - both to allow for the conversion from liquid to gas, AND for expansion from external heating of the tank and contents. Thus, tanks should never be filled to more than 80% of capacity.

Anyone who fills beyond that 80% point is both ignorant of the extreme explosion risk, and doesn't respect common safety procedures.
__________________
Chateau_Nomad is offline   Reply With Quote
Old 11-23-2021, 02:39 PM   #7
Senior Member
 
OldWEB's Avatar
 
Brand: Thor Motor Coach
Model: FW Hurricane 33T
State: England
Posts: 775
THOR #16471
The "spit valve" is a sure way to know the tank is "FULL", that is 80% of the tank capacity. Relying on the overfill device to stop at 80%.... what if it doesn't? Also 75% or 80%... how much accuracy do you need?
To the OP, the potentiometer/gauge on the tank can be removed, cleaned (where the two faces meet) and that gives you an idea on how it works, etc. but try to trust the tank gauge.
__________________
OldWEB is offline   Reply With Quote
Old 11-23-2021, 02:39 PM   #8
Senior Member
 
Bob Nodine's Avatar
 
Brand: Thor Motor Coach
Model: Quantum JM31
State: Tennessee
Posts: 224
THOR #21926
Quote:
Originally Posted by Chateau_Nomad View Post
The local outfit where I get my propane explained it this way - after I noticed it wasn't completely full according to the tank gauge:

"FULL" in a propane tank takes into account the expansion and internal pressure of the tank. Propane is stored as a "liquid propane gas" (LPG) which changes from a liquid to a gas before it is expelled under pressure from the tank. That conversion happens VERY quickly - as does expansion of the tank contents from external heat.

There is what's called the "80% Rule" with propane. 20% of the tank MUST be available for expansion - both to allow for the conversion from liquid to gas, AND for expansion from external heating of the tank and contents. Thus, tanks should never be filled to more than 80% of capacity.

Anyone who fills beyond that 80% point is both ignorant of the extreme explosion risk, and doesn't respect common safety procedures.
That is what the bleed valve is all about. There are tubes in tank that travel up into the 20% vapor area. The output for the coach is one and all the appliances only use vapor and not liquid. The bleed valve should be opened when filling the thank and when the liquid reaches the 80% mark liquid will come out of the bleed valve. That is when the tank is full leaving 20% above the liquid for vapor.
__________________
Bob
2022 Quantum JM31, 2020 Chevy Sonic
Bob Nodine is offline   Reply With Quote
Old 11-23-2021, 03:08 PM   #9
Senior Member
 
Brand: Thor Motor Coach
Model: Chateau 24F
State: Ohio
Posts: 1,407
THOR #16721
Quote:
Originally Posted by Bob Nodine View Post
That is what the bleed valve is all about. There are tubes in tank that travel up into the 20% vapor area. The output for the coach is one and all the appliances only use vapor and not liquid. The bleed valve should be opened when filling the thank and when the liquid reaches the 80% mark liquid will come out of the bleed valve. That is when the tank is full leaving 20% above the liquid for vapor.
Exactly. You'll notice the tech who's filling even a small 20# grill tank uses the same technique - they have a relief valve on the hose nozzle and the tank is sitting on a very accurate scale. From experience they know how much it should weigh at the 80% fill point (tank weight + LP weight).
__________________
Chateau_Nomad is offline   Reply With Quote
Old 11-27-2021, 07:31 PM   #10
Senior Member
 
Brand: Thor Motor Coach
Model: 29h outlaw
State: New Jersey
Posts: 431
THOR #5248
Are you sure you are reading the tank properly?
My tank gauge is in quarters, where the leds are in thirds.
__________________
Trkyte@msn.com is offline   Reply With Quote
Old 11-28-2021, 12:44 AM   #11
Senior Member
 
OldWEB's Avatar
 
Brand: Thor Motor Coach
Model: FW Hurricane 33T
State: England
Posts: 775
THOR #16471
Quote:
Originally Posted by Trkyte@msn.com View Post
Are you sure you are reading the tank properly?
My tank gauge is in quarters, where the leds are in thirds.
Hey, you may be onto something here that I have wondered about myself... The LEDs may be in thirds, cuz realistically we can only use 80% of the volume, so let us say 75% and now that can be broken down to thirds! 25% - one LED(⅓); 50% - 2 LEDs(⅔); 75% (or full) - 3 LEDs
and that is easily identified on the gauge.
It has been staring ME in the face the whole time! Thanks!

__________________
OldWEB is offline   Reply With Quote
Old 11-28-2021, 01:03 AM   #12
Member
 
Brand: Thor Motor Coach
State: Oregon
Posts: 53
THOR #20539
2018 Citation

My firefly reading is not in 1/3’s…it’s actual…and at 50% it takes just about 8 gallons…when full the firefly reads full and the outside gauge is between 3/4 and full…near enough for me…now, those grey and black gauges, they are useless…:haha!
__________________
Harmsy is offline   Reply With Quote
Old 11-28-2021, 10:58 AM   #13
Senior Member
 
Bob Nodine's Avatar
 
Brand: Thor Motor Coach
Model: Quantum JM31
State: Tennessee
Posts: 224
THOR #21926
Quote:
Originally Posted by Harmsy View Post
My firefly reading is not in 1/3’s…it’s actual…and at 50% it takes just about 8 gallons…when full the firefly reads full and the outside gauge is between 3/4 and full…near enough for me…now, those grey and black gauges, they are useless…:haha!
The typical RV motorhome propane tank that has a metal plate stating the capacity is 12.2 gallons will only hold about 9.5 gallons or less. How much it holds depends on where the overfill protection device shuts off the input port. I am guessing your coach has a 20 gallon propane tank and the 80% volume is 16 gallons. Your system has been calibrated to indicate 100 % at 16 gallons. We have installed the SeeLevel system on our coach and have calibrated the LP gauge on the SeeLevel to 100% with the tank full. Time will tell how accurate that will be but we are expecting the tank to accept around 5 gallons when the gauge says 50%.
__________________
Bob
2022 Quantum JM31, 2020 Chevy Sonic
Bob Nodine 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


» Featured Campgrounds

Reviews provided by

Disclaimer:

This website is not affiliated with or endorsed by Thor Industries or any of its affiliates. This is an independent, unofficial site.




All times are GMT. The time now is 09:18 AM.


Powered by vBulletin® Version 3.8.8
Copyright ©2000 - 2022, vBulletin Solutions, Inc.
Content Relevant URLs by vBSEO 3.6.0 PL2