Fridge not cooling properly

[GallenH]

I have a 1997 Pleasure Way with original 3-way Dometic fridge. Got the RV from my father in law about 3 years ago and everything has worked fine....up to now. It won't cool down enough. Problem on 12v, 120v, propane. Doesn't matter. I logged today (in Phx 106 deg high). 7:00am 32deg. by 7:00pm 68deg. That's on electric. Yesterday test on LP by 7:00pm; 80deg. Suggestions for what to look at? First encountered problem on recent trip to mountains. There the daytime temp was 85. Could only get the fridge down to about 55deg (LP). Driving home (12v) no better.

Any guidance appreciated.

[hbn7hj]

Everyone will have different ideas on this. Personally, after 20 years, I would buy a new 3-way refrigerator and call it done.

I would not install a compressor fridge even though they work better. The power requirements would require a new electrical system.
Harry

[Bruceper]

Originally Posted by hbn7hj

I would not install a compressor fridge even though they work better. The power requirements would require a new electrical system.

Please explain this statement.

[InterBlog]

Hi, Gallen. As the owner of (I'm embarrassed to say it) three Class B fridges inside four years, I feel your pain. We had trouble with both of our Dometic 2351 propane models, to the point where we couldn't use them on the road. We eventually got a Vitrifrigo, which is a marine-grade compressor fridge, and have been very happy with it so far, even in the Texas heat. If you are interested, you can read about our sorry three-fridge adventure in a blog post here.

We were able to rehab both of our Dometics simply by burping them, believe it or not. There's plenty of flap-trap on the internet about how burping is an urban myth or whatever, but it worked for us. We just turned those suckers upside down for a few minutes, flipped them back upright, and voila - they started cooling again.

That's rather impractical for a propane fridge installed in a van, however. But it's a zero cost first intervention measure. If you de-install your fridge and burp it and it does NOT restore functionality, then you know you've got bigger problems and you can move on to other testing.

As an anecdote, rather than sell our Lazarus fridges (as I call them) on Craigslist, we decided to combine them to make an off-grid fridge for our garage. This was my husband's idea - he is a "DIY or die" kind of person (so am I actually). We live in hurricane country (Galveston County TX), so this could be very useful to us in the event of a significant power failure. We also had a Lifeline AGM battery and an electrical converter left over from our van's lithium conversion, plus a spare propane tank, so we had most of the pieces already in surplus (all except the wood and plumbing). We are in the progress of putting it all together in a contraption that looks like this. The propane bottle will be mounted on top, and I will stain and seal the wood enclosure so that it has a finished look. Nobody in their right mind would set out to make a thing like this from scratch, but we had the parts, so....

[markopolo]

Really high ambient temperatures such as what you are experiencing can actually stop the cooling process in an absorption type fridge. The fridge might not be installed optimally given that it is in a Class B van with limited interior space and sloped exterior walls etc.

This from Dometic themselves:

However, on a hot day (90° or more) even a minor restriction will cause overheating of the cooling unit and the cooling process will slow down or stop.

I'd start the troubleshooting with the dollar bill or piece of paper test. Take a look at the Before You Change That Cooling Unit bulletin from Dometic: https://www.gmcmi.com/wp-content/upl...7-Bulletin.pdf

[GallenH]

Thanks to all of you who have responded. I know that it's hot in PHX. It's always taken overnight+ to get the fridge down to temp. But we've always been able to do it before setting out to cooler temps. We frequently had to turn it down from MAX to a lower setting since the fridge was going into the 30s. So a few more questions:

How does the thermostat factor into this? This model uses a wire going into the cabinet to measure/sense heat. How do I know if it's at fault?

How significant is cleaning the flue.......and how do you do it? I've tried rapping on the chamber but didn't see any rust fall. This model has two side vents......no roof vent.

I don't want to overlook anything before replacing the fridge. I don't believe that I can find one that exact size to fit the cabinetry.

RE burping: I have read about that. I have only a limited understanding but I thought that blockages normally occur because of crystals (sulfate) forming. Something that I read said that while burping might free them from a particular area, they're still floating around to settle somewhere else. Don't know if this is true.

Thx again.

[InterBlog]

Originally Posted by GallenH

...
RE burping: I have read about that. I have only a limited understanding but I thought that blockages normally occur because of crystals (sulfate) forming. Something that I read said that while burping might free them from a particular area, they're still floating around to settle somewhere else. Don't know if this is true.....

I don't know either, and I wasn't able to research it. Propane fridges are well understood in terms of basic chemistry on paper, but a bit of a black box (or a beige box) in actual use. That's one of the reasons why I decided to leave my fridges permanently de-installed. If I need to re-burp in the future because something got re-stuck somewhere, all I need to do is disconnect the wires and plumbing and flip the sucker upside down on my garage floor.

It's a royal pain to de-install a propane fridge from a van. They are sealed up in there so that the products of combustion don't penetrate the living space.

[GallenH]

An interesting setup! Has to be one-of-a-kind. So, I'm guessing from your post that you eventually went with a compressor fridge? Also you must have upgraded the electrical (re your comment about the leftover AGM when you went to Lithium). If I'm going to pull the fridge to replace anyways, I could try burping and connecting it up to 120v in the garage and see what happens with the cooling. I don't believe Dometic makes a replacement with the exact dimensions any more. Not thrilled about modifying cabinetry. If it comes to that I might consider a taller/larger fridge and eliminate the microwave. Never use it anyways since we rarely camp where there's electric.

[Phoebe3]

Originally Posted by GallenH

I don't believe Dometic makes a replacement with the exact dimensions any more. Not thrilled about modifying cabinetry. If it comes to that I might consider a taller/larger fridge and eliminate the microwave. Never use it anyways since we rarely camp where there's electric.

There are other compressor refrigerators out there. InterBlog has a Vitrifrigo and I have a NovaKool. You might find something that fits.

[PJW73NH]

GallenH,Where your issue appears to be consistent on all 3 energy sources (Gas, AC, and DC) I highly suspect the cooling unit itself is the issue. Though high ambient temps and/or ventilation can't be entirely ruled out. If you're somewhat handy with a clamp on ammeter, you can measure the current that each of the heaters draw when in their respective modes (AC or DC). On gas, look for a well formed blue, steady and even flame. If these check out ok and there is good chimney draft and ventilation, I would give burping a try. I have had great success burping absorption fridges in the past 40 years. Yes, it is a REAL PITA to take out of a van, but if you're going to replace it, what's to lose. You can also "bench test" it on AC while it is out.

You didn't mention a model number, but there are a number of troubleshooting manuals online that may be of some value to you. Try a google search with "dometic model RMXXYY troubleshooting" and see what comes up.

Best.

PW