Altitude or attitude? - Fiberglass RV


Reply
 
Thread Tools Search this Thread Display Modes
 
Old 06-18-2020, 09:13 AM   #1
Senior Member
 
MyronL's Avatar
 
Name: Myron
Trailer: Escape
New Mexico
Posts: 861
Registry
Altitude or attitude?

I live here at an altitude of 6700 feet. Well today there seems to be only two conclusions to be drawn. As a 3-way, the Dometic RM8551 fridge in my trailer is a lemon, or, the fridge is adversely affected by altitude. Or both.

It does work great on shore power and on battery power. On propane? Not!

Yesterday I disassembled the burner lines and gave everything yet another thorough cleaning. The 1/8th tubing, the orifice, even the electrodes creating a spark, everything connected to producing a healthy, robust pilot light, all once again cleaned and blown out as best as humanly possible.

Then I turned the fridge on to propane, 5 full dots. When I did that, at 3:40 PM it was 87F in the trailer and 68 in the fridge. At 6:10 PM last night I have a very, very robust pilot light and the chimney is quite hot. (So yes, the regulator pressure is just fine.) But, it was 90 in the trailer, 73 inside the fridge.

This morning at 7:24 AM, after all night on 5 dots propane, it is 64F in the trailer, and --- 55F in the fridge! Terrible.

How can I have such a robust pilot light but no commensurate propane cooling? See that towel over there? Just threw it in. To paraphrase an old Frank song… My story is much too sad to be told, but everything seems impossibly un- cold.

This is all insanity. When looking for a replacement fridge for your rv before paying the big bucks you need to know the following criteria.

First, will it fit through the door of the trailer?
  • Is it the right size for your cabinet area?
  • Will it work in hot weather?
  • Will it work at the altitude you will be camping at?

Does Dometic tell you that? Not that I can find. I heard they make a fridge specifically for tropical zones (Australia?) but apparently they are keeping that a secret here in the US. Zero reference if they also make a fridge for higher elevations. The Dometic website is such a jumble, so slick, but absurdly inept for the real world.

Note I did include the word “attitude” starting this topic.
Attached Thumbnails
pilot2.jpg   frigb4c.jpg  

__________________

MyronL is offline   Reply With Quote
Old 06-18-2020, 09:26 AM   #2
Senior Member
 
FRED SMAILES's Avatar
 
Name: Fred
Trailer: 13 ft Boler
Kootenay's of BC
Posts: 910
Registry
I have the same problem, at sea level.
Works on shore power but not propane although the propane seems to be heating correctly.
But I haven't torn mine apart yet.
Fred
__________________

__________________
I'd rather do it myself, done right or not. Isn't that what a hobby is all about?
https://www.fiberglassrv.com/forums/...ler-55601.html
FRED SMAILES is online now   Reply With Quote
Old 06-18-2020, 09:34 AM   #3
Senior Member
 
Alex Adams's Avatar
 
Name: Alexander
Trailer: 1979 Boler B1300
New Hampshire
Posts: 632
There have been a few owners who found that the way the factory installed the fridge was causing problems with cooling. I believe they changed the baffling in the cabinet so the movement of air across the back of the fridge was enhanced. You can try searching for the threads or maybe one of them will pipe up. I don't have a propane fridge. The newer 12 volt compressor fridges work really well. I'm using a portable Dometic currently but plan on installing one permanently in my boler.
Alex Adams is online now   Reply With Quote
Old 06-18-2020, 09:54 AM   #4
Senior Member
 
MyronL's Avatar
 
Name: Myron
Trailer: Escape
New Mexico
Posts: 861
Registry
Been there done that, Alex. A waste of time.

Thinking, wouldn't it be swell if some suit working at Dometic reads this post and makes the effort to address my issues? They don't take phone calls and they ignore emails, soooo....??
MyronL is offline   Reply With Quote
Old 06-19-2020, 01:41 PM   #5
Senior Member
 
Name: Wayne & Barbara
Trailer: Parkliner
Iowa
Posts: 1,097
Absorption Fridges

The absorption type fridges can cool only so many degrees below the ambient temperature. So the hotter it is outside, the warmer it will be inside the box.
The rear of the fridge needs to have plenty of outside air circulation over the condenser coils to dissipate the heat extracted from the food inside.
you can see, that "cooling" the condenser with "hot" air is a no win situation.
Some of us bring a plastic bottle(s) of frozen water inside the box to help keep it cold.
Wayne Collins is offline   Reply With Quote
Old 06-19-2020, 02:52 PM   #6
Senior Member
 
Byron Kinnaman's Avatar
 
Name: Byron
Trailer: 2006 Scamp 13' towed with a 2005 Dodge Dakota 4.7l Magnum W/full tow package (over kill)
Oregon
Posts: 7,041
Registry
Most of what was said needs to be listened to. Now violated expectations seems to the rule when it comes to refrigeration. These things don't cool the same way your home fridge does. The easiest thing to do is get over it and don't carry sensitive foods. Learn from backpacking books how to carry non refrigerated foods,
__________________
Byron & Anne enjoying the everyday Saturday thing.
Byron Kinnaman is offline   Reply With Quote
Old 06-19-2020, 04:40 PM   #7
Member
 
Name: Wil
Trailer: 2010 Casita 17' SD
Washington
Posts: 81
Quote:
Originally Posted by Alex Adams View Post
e. The newer 12 volt compressor fridges work really well. I'm using a portable Dometic currently but plan on installing one permanently in my boler.

I'm not familiar with 12v compressor refers for RVs, but 35 years ago I installed one (an icebox conversion kit) in a 30' sail boat. It came in two pieces, the compressor/condenser unit and the evaporator (freezing) unit that went in the built in icebox, with necessary pre-charged connecting lines. Now you might know that sail boats don't have great battery charging power. Anyway, it worked perfectly with little power drain. As I remember the compressor/condenser unit was rather bulky. I know this doesn't answer the original problem, but if I had problems with my current 3-way I would certainly look into RV compressor refers.
wilyoung is offline   Reply With Quote
Old 06-19-2020, 04:58 PM   #8
Senior Member
 
Name: Gordon
Trailer: 2015 Scamp (16 Std Layout 4) with '15 Toyota Sienna LE Tug
North Carolina
Posts: 4,092
https://www.truckfridge.com/portable...ator-freezers/

I have the TB31A but with a different manufacturer label.. same fridge. AC or DC. Quite efficient and with a good solar battery setup it can replace an absorption fridge for boondocking (except its smaller). There are larger built-in models with the same compressor technology and I think they use nearly the same amount of power.

BTW, a few possibilities.. the chimney is clogged so it gets hot but the heat does not rise that well. Trailer not level. Fridge not insulated. Fridge not installed right (airflow lacking).

Where did you measure the temp? On the cooling fins?
Is 5 half way? Try turning it on max cool setting?
gordon2 is online now   Reply With Quote
Old 06-19-2020, 05:46 PM   #9
Senior Member
 
Name: Dick
Trailer: '15 17' LD Casita and '17 Tahoe LT
Texas
Posts: 247
Mount a couple of computer fans to cool the fins in back of the refer. There are kits made for this that run on 12 volts.
dmad1 is offline   Reply With Quote
Old 06-19-2020, 07:55 PM   #10
Senior Member
 
MyronL's Avatar
 
Name: Myron
Trailer: Escape
New Mexico
Posts: 861
Registry
I am still hoping some genius physics expert reads my initial post and after that understands the issue at hand and will offer useful advice. A real solution.

The prime question I guess, really is... why does altitude, it does seem to be altitude, that adversely affects performance? The magic number seems to be 5500 feet. Yes, my robust pilot light, as I have shown, seems to not produce the heat that produces coldness. But it just ain't going to burn any bigger or hotter. How about cutting open the cooler tubes and replacing the liquid inside with something that does a better job?

My fridge is well insulated, well ventilated (yes, got the two Texas fans in back), and though 6700 feet altitude is not down in the swamp it certainly is not up in the Rocky mountains. I do breathe quite effortlessly on the oxygen we got here so the thinking is if I can do it, so should my fridge.
MyronL is offline   Reply With Quote
Old 06-19-2020, 08:31 PM   #11
Senior Member
 
Name: Dick
Trailer: '15 17' LD Casita and '17 Tahoe LT
Texas
Posts: 247
Could it possibly be the propane regulators? A propane dealer may be able to run a pressure check and see if it is adequate for your altitude.
dmad1 is offline   Reply With Quote
Old 06-20-2020, 01:28 AM   #12
member
 
Name: J
Isle of Wight
Posts: 536
Quote:
Originally Posted by MyronL View Post

The prime question I guess, really is... why does altitude, it does seem to be altitude, that adversely affects performance? The magic number seems to be 5500 feet. Yes, my robust pilot light, as I have shown, seems to not produce the heat that produces coldness.....



Does it work well, on propane, at Sea level?
WizWid is offline   Reply With Quote
Old 06-20-2020, 06:01 AM   #13
Sid
Senior Member
 
Sid's Avatar
 
Name: Sid
Trailer: Parkliner 2014 V6 Jeep Cherokee
Minnesota
Posts: 507
Quote:
Originally Posted by dmad1 View Post
Mount a couple of computer fans to cool the fins in back of the refer. There are kits made for this that run on 12 volts.
https://i5.walmartimages.com/asr/fab...2&odnBg=ffffff

We were in Texas for a week of 90+ degree weather in early June. Knowing what I was in for with the the refrigerator I picked up this USB fan at Walmart. Using a 10k mAH battery pack for power I gave it an overnight and all day trial by placing it in the cabinet blowing up the vent, across the coils.
We stayed at 40 degrees +/_ 2 degrees the whole trip, which I count as a win.
For the few times a year I need it I may just stick with this temporary set up.
Sid
Sid is offline   Reply With Quote
Old 06-20-2020, 08:47 AM   #14
Senior Member
 
MyronL's Avatar
 
Name: Myron
Trailer: Escape
New Mexico
Posts: 861
Registry
RE: post #1, paragraph 2, and all of post #10. (Waaaa)
MyronL is offline   Reply With Quote
Old 06-20-2020, 09:47 AM   #15
Senior Member
 
Jon in AZ's Avatar
 
Name: Jon
Trailer: 2008 Scamp 13 S1
Arizona
Posts: 8,997
Registry
Quote:
Originally Posted by MyronL View Post
RE: post #1, paragraph 2, and all of post #10. (Waaaa)
I deleted my post. While I'm not convinced the referenced sections address all my questions, I realized I had misinterpreted the intent of this thread. Should have paid more attention to the last paragraph of post #1!

You have piqued my curiosity, though. I'm going to test the performance of my own fridge on LP and 110V at 5500' and 7000'. No plans to head to sea level anytime soon, although in a normal year, that's exactly where we'd be right about now. Instead we're parked at home headed into our second heat wave of the season and breathing smoke from several regional fires.
Jon in AZ is online now   Reply With Quote
Old 06-20-2020, 10:50 AM   #16
Senior Member
 
MyronL's Avatar
 
Name: Myron
Trailer: Escape
New Mexico
Posts: 861
Registry
Roger that, Jon. No worries... this issue is a pretty old one. I am just hoping this thread piques the interest of any of the geniuses out there on line, gets them to read carefully, motivates and ponder a true remedy. Hey, geniuses, consider this a homework assignment. All others need not respond.

Got friends around Tucson... saw the news pix. You have my sympathy.
MyronL is offline   Reply With Quote
Old 06-20-2020, 11:18 AM   #17
Senior Member
 
Raspy's Avatar
 
Name: John
Trailer: Black Series HQ19
Smith Valley, Nevada
Posts: 2,064
Myron,

I have a friend with a Dometic fridge in their new trailer that would not cool, no matter how long it was left burning. An RV repair shop gave up on it and said it was "defective".

I found out the trailer had been parked on a severe angle at the dealer, with the system running, and after that it would not work. A popular, old fashioned fix for absorption fridges is to turn them upside down for a while, after they have been out of level enough to make them stop cooling. They have to be fairly level, or used while driving.

I suggested something to try before giving up completely, or pulling it out to turn it upside down.

I asked them to start it and leave it running for a while, maybe several hours to get the hot part fully warmed up, and the absorption hot enough to work. And then take it for a drive. During the drive I asked them to be sure and go around lots of corners and over some bumps.

They did this and it fixed it. It is now working normally.

In reading your story, you repeatedly commented how big the flame was. "Robust, turned up to 5 dots, ain't gonna burn any bigger".

I wonder if the flame is too big? The flame doesn't burn bigger to make more cold, it burns longer. Older ones would turn way down when the box was cold and up to make more cold, but that was just so they could stay lit as a pilot light. Small in that case, was a pilot light, big was the working flame. Newer ones go out and then re-light when more cold is needed. But they don't just turn up to a bigger flame to make more cold. Bigger is not necessarily better. Bigger doesn't necessarily equal more cold.

Someone mentioned that they can only go a certain amount colder than ambient, and that might be the problem in your case. It is not the problem. Absorption systems do have their limits, but mine, for instance was 6 degrees F in the freezer compartment today while outside temp was 90. And yours works on 120 volts. So you are not out of its working range.

So, you might have the dreaded bubble problem, that can be solved by driving it around while it is trying to cool. Or you might have too large of a fire that is overwhelming it. The latter is just a theory and I have never seen that happen, but you repeatedly commented how big the fire is. Turn it down. Or restrict it somehow and see if that helps. It is not about giving it more and more fire to get cooler and cooler. All it has to do is boil the ammonia to separate it from the water, and cause hydrogen bubbles to form. The boiling point in the system is probably a little over 100* F.

While it is on, the heat should be getting all through the finned tubing on the rear of it. Compare the temp of the tubing when running on 120 volts, with the temp while running on propane. This will prove that the flame heat is getting into the system and it will show you how much heat is needed to cool the box on 120 volts. Way more heat there from the flame might be the problem.
__________________
I only exaggerate enough to compensate for being taken with a grain of salt.
Raspy is offline   Reply With Quote
Old 06-20-2020, 11:36 AM   #18
Senior Member
 
Name: Gordon
Trailer: 2015 Scamp (16 Std Layout 4) with '15 Toyota Sienna LE Tug
North Carolina
Posts: 4,092
Quote:
Originally Posted by MyronL View Post
... All others need not respond.
...
I'm sorry I did, even though my suggestion is a valid one to consider. That is all I will say about this approach you are taking to getting advice.
gordon2 is online now   Reply With Quote
Old 06-20-2020, 12:12 PM   #19
member
 
Name: J
Isle of Wight
Posts: 536
Quote:
Originally Posted by MyronL View Post
RE: post #1, paragraph 2, and all of post #10. (Waaaa)
Please answer post #12.
WizWid is offline   Reply With Quote
Old 06-20-2020, 02:37 PM   #20
Senior Member
 
MyronL's Avatar
 
Name: Myron
Trailer: Escape
New Mexico
Posts: 861
Registry
Thanks for asking.

Fridge on battery, towing to Albuquerque. Plan was to get to a big parking lot in ABQ then switch from battery power to propane and wait, to see what happens with the fridge cooling on propane at the lower altitude.

Time --Fridge temp --Trailer temp --observation
10:40 am 64 71 At home, 6700 ft elevation - Turn fridge on battery power 5 dots
11:13 am 63 73 - -Arrive Home Depot, ABQ, Switched fridge to propane 5 dots
11:26 am 62 - --Home Depot parking lot - 5,474 ft elevation
12 noon 58 79 ---Looking good.
1 PM 57 83 - -- Drive to Cabellas, elevation 5,148 ft, It's dropping, still on propane 5 dots.
2:40 pm 64 89 - -Arrive now back home, and still on propane.
__________________

MyronL is offline   Reply With Quote
Reply


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools Search this Thread
Search this Thread:

Advanced Search
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


Similar Threads
Thread Thread Starter Forum Replies Last Post
High altitude affecting gastrointestinal system?? Bhamm1 General Chat 24 06-24-2020 09:06 PM
Towing and Altitude Adjustment Pete Dumbleton Problem Solving | Owners Helping Owners 4 07-27-2007 03:37 PM
Trailer Ride Attitude.... Doug Mager Problem Solving | Owners Helping Owners 8 06-18-2007 04:00 PM
Towing attitude Taylor Kissinger Towing, Hitching, Axles and Running Gear 6 09-18-2006 06:45 AM

» Upcoming Events
No events scheduled in
the next 465 days.
» Featured Campgrounds

Reviews provided by


All times are GMT -6. The time now is 08:29 AM.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2020, vBulletin Solutions Inc.
×