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msinabottle Samba Member
Joined: September 20, 2005 Posts: 3492 Location: Denver Area, Colorado
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Posted: Tue Mar 13, 2007 7:53 pm Post subject: A Fix for High-Altitude Dometics on Propane |
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There's a subject that grabs the eye, don't it?
All right--in the Westy manuals, and reproductions thereof, you can read that for operation above 6,000 feet, you need to replace the No. 24 Jet in your Dometic Fridge's propane burner with a No. 22 Jet. Try getting one. I did. People had no idea what I was talking about. And, as an FYI, a replacement No. 24 jet, which I did find, was a mere $74. Winston's fridge goes out at 7,000 feet, and that's where I camp in him all Summer.
Searched and searched... And over the years on the old Vanagon List this solution appeared:
Quote: |
Actually, I have it from a very good Dometic Service center that Dometic Service Bulletin recommends turning the pressure regulator down to as low as 5 w.c. inches for altitudes over 8,000 feet.
I could not keep mine light until I turned it down to 10 w.c. inches... I live at 6300 feet.
It may be that there are different size jets for different years of production of the Dometic Fridge.... or there may be variation in the oxygen tubing.... Other than this, the only reason I can think of as to why your fridge works so well over 9,000 feet is perhaps your propane pressure is turned down an you don't know it? .... have you checked yours lately???
In any case, it seems that the fridge's are more likely to work better on less than 11 w.c. inches at high altitudes/not more.... there is less air for combustion at altitude and turning the pressure down gets the gas/air mixture more in the direction of what it would be at lower elevations. |
And eventually I learned that you can do that at the regulator, which is on the outside of the van.
Well, that's promising! And the people who put in my new inlet valve and checked over my system can probably do that. It's a solution! Run the fridge on AC the night before, run up to camp, and hope the range still works on lowered gas pressure.
Of course, I want more. What I'd really like was some means to reduce pressure JUST into the fridge that I could turn off and on at will--'will' to be defined as, 'Whenever I'm above 6,000 feet!' On the Vanagon list some talked about installing a 2nd regulator on just the fridge gas line. Someone else said that's a bad idea--regulators can dump gas to prevent overpressure, NOT a good idea inside a cab.
Anybody got any other ideas on how to reduce pressure for just the fridge? Valve set to a set diameter? I'm very open to suggestions!
Best! _________________ 'Winston,' '84 1.9 WBX Westy
Vanagon Poet Laureate: "I have suffered in
many ways, but never, never, never in silence." |
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?Waldo? Samba Member
Joined: February 22, 2006 Posts: 9752 Location: Where?
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Posted: Tue Mar 13, 2007 8:27 pm Post subject: |
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You could run a second propane regulator in the line to the fridge it could be set at any desired pressure, but obviously would only have the ability to lower the pressure below that of the primary regulator. You could also place a single strand of fine multi-strand copper wire into the orifice of the jet. I've done that on carburetor jets with success. My fridge is a bear to light, but stays lit just fine at 7,000 ft. Good info regardless. I don't think I would have thought of a second reg if you hadn't brought up the topic. Cheers.
Andrew |
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BigBlueWesty Samba Member
Joined: October 06, 2014 Posts: 23 Location: Colorado
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Posted: Mon Oct 06, 2014 9:00 pm Post subject: |
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Did you ever find a fix for this? I think I may have the same problem. I just got an '87 westy. I tested everything out in the drive way and everything worked great. I even got the fridge running on propane. Went camping for the first time this weekend (at about 8,000 feet). When I got to the camp site I noticed the fridge was out. Tried lighting it again and I could get it lit but it wouldn't stay lit. I could only get it to stay lit if I kept pumping air into it. So it would seem it is not getting enough air flow. Tried it again when I got back home (5,000 feet) and the fridge stays lit with no problem, even made ice cubes! Is it possible to get this thing to work at altitude? |
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Rodknock Samba Member
Joined: April 06, 2006 Posts: 516 Location: Boulder CO
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Posted: Tue Oct 07, 2014 7:19 am Post subject: |
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I have had success with my stock fridge at altitudes up to 12000 feet. It can be done and you have to have everything in tip top shape. The rubber gasket on the side of the van has to seal completely on both sides, and the screws have to be good and tight (one of mine was stripped so I put a slightly larger screw in there to get it tight). Hi temp gasket sealant is helpful too. The combustion chamber also has to be totally sealed up. Finally, I blow compressed air into the tube below the fridge occasionally and watch all the dust come out the of the vent. It may be hard to get it lit above say 9000 feet, but it will eventually light and stay lit if everything is working perfectly.'
BTW - I don't drive more than a mile or two with the fridge on propane. I put it on battery power when driving. I can't imagine why someone would run it on propane and use up propane when the battery/alternator power is there and free. I keep reading posts from people who want to run it on propane while driving and it baffles me. Perhaps they don't want to go through the hassle of lighting it again? |
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MarkWard Samba Member
Joined: February 09, 2005 Posts: 17153 Location: Retired South Florida
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Posted: Tue Oct 07, 2014 7:30 am Post subject: |
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I was recently camping in Colorado at 10K feet. I could light the fridge and it would stay lit as long as I was stationary. It works fine at lower altitudes even underway. I actually posted a question here and had missed this thread. I got some of the same recommendations. It is probably not practical to replace the jet when at altitude.
As far as using the battery when underway. My understanding was that the Dometic on 12 volt was the least effective of the 3 ways to cool. _________________ ☮️ |
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BigBlueWesty Samba Member
Joined: October 06, 2014 Posts: 23 Location: Colorado
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Posted: Tue Oct 07, 2014 7:32 am Post subject: |
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Thanks for the tips. Have you taken the fridge out before for maintenance? What kind of compressed air are you blowing through the condensation drain? Are you using a compressor or a bike pump? I'm afraid to blow anything to strong through there, but I suspect some dirt or rust flakes are blocking a little airflow and causing my problem. I'll check my flue seal again too.
Thanks! |
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Rodknock Samba Member
Joined: April 06, 2006 Posts: 516 Location: Boulder CO
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Posted: Tue Oct 07, 2014 8:05 am Post subject: |
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BigBlueWesty wrote: |
Thanks for the tips. Have you taken the fridge out before for maintenance? What kind of compressed air are you blowing through the condensation drain? Are you using a compressor or a bike pump? I'm afraid to blow anything to strong through there, but I suspect some dirt or rust flakes are blocking a little airflow and causing my problem. I'll check my flue seal again too.
Thanks! |
I think the air pressure is about 60-80 psi. I would not over do it. I have indeed had my fridge out and had installed an air pump upgrade kit from GW that had no affect whatsoever. I installed a bigger fan and that didn't do much either. I cleaned out the combustion chamber too but it was not bad at all. When I fixed the seal of vent on the side of the van is when the fridge started working a lot better. Also, be careful of how you re-assemble the vent on the side of the van. One time I had the inner plate rotated incorrectly and had real problems keeping the fridge lit. I would check this.
Last edited by Rodknock on Tue Oct 07, 2014 3:43 pm; edited 1 time in total |
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Rodknock Samba Member
Joined: April 06, 2006 Posts: 516 Location: Boulder CO
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Posted: Tue Oct 07, 2014 8:10 am Post subject: |
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More recently I changed the city water hook-up to a vent, but have not tested the effectiveness of this yet....
It may help in really hot weather. I think ideally the vent would be under the fan on the back of the fridge so cool air could be pulled up over the cooling fins. Maybe there is a rubber body plug under there that could be utilized. I sorta recall seeing rubber body plugs under there. |
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DLJ Samba Member
Joined: August 05, 2008 Posts: 555 Location: North California
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Posted: Tue Oct 07, 2014 11:09 am Post subject: dometic |
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I personally havent had any trouble with my Dometic at higher altitudes, but will admit that may be a problem for some. I repair and service Dometics and would like to suggest that in order to get a little more air into the burner box unscrew the little cover on the drain tube (bottom of refer) this might allow sufficient oxy to eliminate high altitude trouble. It IS critical for a good flue/exhaust seal to body on the outside. Also next time refer is out, check for small cracks in intake and exhaust . You may also do well to insulate the high tension wire from piezo to electrode. This alone will help starting on propane.
Regarding 12V operation, its the least efficient way to cool, and the saving of propane is very minimal. |
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MarkWard Samba Member
Joined: February 09, 2005 Posts: 17153 Location: Retired South Florida
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Posted: Tue Oct 07, 2014 12:36 pm Post subject: |
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Good tip about the drain cover. I will certainly try that next year when I get out west. I live at sea level. _________________ ☮️ |
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msinabottle Samba Member
Joined: September 20, 2005 Posts: 3492 Location: Denver Area, Colorado
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Posted: Tue Oct 07, 2014 2:15 pm Post subject: Pretty Much the Same |
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Well, for starters, I'd never think of running the Dometic without that drain plug open--propane creates moisture when it burns, and you want that water OUT of the burner box. You do cap that thing at all other times to keep out the multi-legged brigade.
I agree with what every one else said--what worked for me was to give up trying to make a new rubber gasket for the burner box, I used that Form-a-Gasket Copper-based high temperature stuff the last time I pulled the fridge and did much besides, for which see HERE:
http://www.thesamba.com/vw/forum/viewtopic.php?p=6019385&highlight=dometic+sealant#6019385
I checked the vent tubes for leaks and baby-oiled the rubber external gaskets, which seem to like that. Since all the drill in that post, the Fridge has lit at high altitude--that 7,000 feet again--and stayed running while driving below that. What's above is also good advice, but, that's my contribution.
Best! _________________ 'Winston,' '84 1.9 WBX Westy
Vanagon Poet Laureate: "I have suffered in
many ways, but never, never, never in silence." |
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BigBlueWesty Samba Member
Joined: October 06, 2014 Posts: 23 Location: Colorado
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Posted: Tue Oct 07, 2014 2:42 pm Post subject: Re: Pretty Much the Same |
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msinabottle wrote: |
I checked the vent tubes for leaks and baby-oiled the rubber external gaskets, which seem to like that. Since all the drill in that post, the Fridge has lit at high altitude--that 7,000 feet again--and stayed running while driving below that. What's above is also good advice, but, that's my contribution.
Best! |
So did you ever do any mods to your regulator?
Thanks for the advice everyone. I was going to try unscrewing the drain plug next time I'm at altitude. It should help with airflow. I'll also check my vent/flue seal. One of the dometic bulletins mentioned that the disk inside shouldn't be warped. I think mine might be. Does that matter?
Thanks again. |
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msinabottle Samba Member
Joined: September 20, 2005 Posts: 3492 Location: Denver Area, Colorado
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Posted: Tue Oct 07, 2014 3:06 pm Post subject: Only One |
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Quote: |
So did you ever do any mods to your regulator? |
Only one, of my scores of modifications to Winston, perhaps the one that deserves the most additional attention:
http://www.thesamba.com/vw/forum/viewtopic.php?p=3760766&highlight=aaa+propane+hose#3760766
DO THAT ONE. But, nope, just the gasket made the difference.
I really would NEVER run the fridge on propane without that drain open.
Best! _________________ 'Winston,' '84 1.9 WBX Westy
Vanagon Poet Laureate: "I have suffered in
many ways, but never, never, never in silence." |
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BigBlueWesty Samba Member
Joined: October 06, 2014 Posts: 23 Location: Colorado
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Posted: Tue Oct 07, 2014 3:23 pm Post subject: Re: Only One |
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Quote: |
But, nope, just the gasket made the difference. |
Do you mean the gasket on the outside flue/vent? |
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Rodknock Samba Member
Joined: April 06, 2006 Posts: 516 Location: Boulder CO
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Posted: Tue Oct 07, 2014 3:41 pm Post subject: Re: Pretty Much the Same |
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BigBlueWesty wrote: |
msinabottle wrote: |
I checked the vent tubes for leaks and baby-oiled the rubber external gaskets, which seem to like that. Since all the drill in that post, the Fridge has lit at high altitude--that 7,000 feet again--and stayed running while driving below that. What's above is also good advice, but, that's my contribution.
Best! |
So did you ever do any mods to your regulator?
Thanks for the advice everyone. I was going to try unscrewing the drain plug next time I'm at altitude. It should help with airflow. I'll also check my vent/flue seal. One of the dometic bulletins mentioned that the disk inside shouldn't be warped. I think mine might be. Does that matter?
Thanks again. |
Yes, the disk matters a lot. If it isn't in there properly it will cause your fridge combustion to burn well, then flicker low, then burn well again, like that over and over until it goes out completely. This one baffled me for weeks until I finally figured it out, and it was my own fault for not assembling it correctly. |
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BigBlueWesty Samba Member
Joined: October 06, 2014 Posts: 23 Location: Colorado
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Posted: Wed Oct 08, 2014 7:58 am Post subject: |
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I came across this article about flue assembly http://shufti.wordpress.com/2010/08/11/dometic-fridge-flue-assembly/
The author says to caulk the rubber gasket to the side of the van. That seems like a bit overkill. But it got me thinking. When I pulled my gasket off there seemed to be some old residue on the back of it. Were these things originally glued on to the side of the van? |
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DLJ Samba Member
Joined: August 05, 2008 Posts: 555 Location: North California
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Posted: Wed Oct 08, 2014 2:57 pm Post subject: dometic |
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Regarding the flu seal to outside of van, I repeat, it is very critical. I never use any sealant or caulking, but cant see where this would hurt. If in doubt, seal it. Also the baffle between vent and van must not be bent. If you look, you will see that the baffle and the flue cover are keyed to each other, cant assemble wrong.
FYI the eurovan refrigerator (norcod) is very similar to the Dometic. Early
eurovans came with one outside intake/exhaust vent. Later models came out with their so called, "high altitude model" Two outside vents ! One above the other. Theoretically giving twice the efficiency. This however has not been my experience. |
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msinabottle Samba Member
Joined: September 20, 2005 Posts: 3492 Location: Denver Area, Colorado
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Posted: Wed Oct 08, 2014 3:05 pm Post subject: No... |
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The gasket that made the great improvement in how the Dometic stayed burning was the one I made with the Copper Hi-Temp Sealant on two parts of the box around the burner jet itself.
Best! _________________ 'Winston,' '84 1.9 WBX Westy
Vanagon Poet Laureate: "I have suffered in
many ways, but never, never, never in silence." |
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BigBlueWesty Samba Member
Joined: October 06, 2014 Posts: 23 Location: Colorado
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Posted: Wed Oct 08, 2014 6:20 pm Post subject: Re: dometic |
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DLJ wrote: |
Also the baffle between vent and van must not be bent. |
Just so I'm clear by baffle you mean the disk in the middle of the assembly? Sort of rests on one of the vent tubes? This should be flat like a coin? Mine is sort of convex. Anyone know where I can get one of those? Couldn't find it on Gowesty. |
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BigBlueWesty Samba Member
Joined: October 06, 2014 Posts: 23 Location: Colorado
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Posted: Wed Oct 08, 2014 6:27 pm Post subject: Re: No... |
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msinabottle wrote: |
The gasket that made the great improvement in how the Dometic stayed burning was the one I made with the Copper Hi-Temp Sealant on two parts of the box around the burner jet itself.
Best! |
Thanks, I want to avoid pulling the fridge for now. I've vacummed it and blown air through it and it seems pretty clean. |
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