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

[GallenH]

Hey thanks for the link. Only just went there. It will be my checklist for the weekend..

[Doneworking]

First thing I would do is check the seal around the door. A twenty year old unit in Arizona is going to get really hot in time and the seals don't last forever.

I had a rig once that had a poor seal. I sprayed it with silicone and let that soak in to revitalize the rubber and then wiped up the excess. Then, I put a couple of layers of black electrical tape around the opening where the door seal meets the refrigerator. That added a fraction of an inch and caused the seal to meet more tightly.

Worked fine. If it doesn't you haven't spent any money and only used about fifteen minutes of your time to find out.

Also, I would take the exterior vents refrig vents off and position a household fan up to that height and turn it on while attempting to cool the refrig. This obviously increases the airflow around the coils and tests that part of the unit a bit. If you run it on propane when doing this, protect the flame from receiving the wind from the fan.

Paul

[mloganusda]

On my prevision Rialta, I installed a computer fan blowing air onto the coils during high temperatures. This increases air flow and makes the frig. work better in high temps. You have 12v at the rear of the frig. and you can use a thermostat to control when the fan comes on and off.

MLogan
Smyrna, TN

[SteveJ]

Look for fans with a thermistor already attached. Amazon has them. They work well and are simple to wire in. I put a mini toggle switch in the fridge panel when I replaced the fridge but any place that you can work with should be good.

On TDY near Mammoth Lakes CA

[GallenH]

I went around the door gasket with the "dollar bill" test and it appears ok. I get a bit of a suction grip when I try to open the door which I assume is good. One of the early tests that Dometic suggests to their techs is to start up the unit and after 2 hours compare the temp of the insulation pack around the heater to the absorption coils. My temps were pretty close. I've got an IR temp reader. According to them, that's a good preliminary sign. Right now I'm doing the 12hr test to see what interior temp is. But the thought of an auxiliary fan is a good one. That PleasureWay doesn't have a roof vent but relies on the 2 side vents.

How did you guys fasten your fans? Did you point them at the coils? Or pointing upwards? I actually saw a product which is a vent that replaces the top vent and has a fan attached; I assume blowing out to draw air from the bottom vent past the fridge. Anyone try this?

And, if I didn't say it before, thanks to all of you for your suggestions/help.

[Doneworking]

My RT has a vent at the top and bottom. I mounted the fan behind the bottom vent and pointed it straight up so the ventilation draft would be across the coils and follow the natural path of hot air rising. I bought mine years ago but it was pretty close to this in appearance:

https://www.amazon.com/Rosewill-Bear...s=computer+fan

I was surprised to see this three pack for a reasonable price. They make these things of various size and voltage and, of course, you need a 12 volt. I fashioned a simple mount out of a small L bracket and just attached it that way. I also put in a simple SPST toggle switch I probably had on hand. I just took power from where it was available coming to the back of the refrig and since the little fan draws only a small amount of milliamps I didn't make this a fuss.

At the price of these in the link, I might put in two fans if I were doing it again.

All I can tell you is I live in Oklahoma City and we have HOT weather here. It really helps the refrig in the summer time and I just flip it on and leave it on when we are travelling.

No rocket science here, just a real simple device to assist the flow of the air across the coils.

My wife puts one of these inside the refrig to provide a little circulation.

https://www.campingworld.com/fridgec...-on-off-switch

It seems to make a difference of a few degrees. The thing runs forever it seems on the two batteries and you don't have to wire anything. Probably to small to use to move air for the outside coil but works good to circulate the cooler air around inside the refrig.

Paul

[Gary Mn]

I just replaced my nine year old three way with a Novakool 4500 12/130 volt compressor unit. It is pricy but works much better than the absorption one. We travel each day and a 224 amphr coach battery which keeps our battery charged. It keeps temps stable and recovers fast. Very happy with it

[mloganusda]

Photo of refig cooling fan.

MLogan

Smyrna, TN

[DWorrell3]

I have a 2012 RT Popular and I have never seen my refrigerator cool 40 degrees below ambient. In other words, if it's 104 in Lubbock, TX, the fridge is not going below 64 degrees, however it's hooked up. I took it out and put in a NovaCool compressor fridge, which fit perfectly in the available space. It will hold 36 degrees, no matter what. I can run it on coach batteries alone for three days, and it will run on shore power and the generator. I'ts my understanding that the expansion fridges are being gradually phased out. Dave W

[Gary Mn]

Originally Posted by DWorrell3

I have a 2012 RT Popular and I have never seen my refrigerator cool 40 degrees below ambient. In other words, if it's 104 in Lubbock, TX, the fridge is not going below 64 degrees, however it's hooked up. I took it out and put in a NovaCool compressor fridge, which fit perfectly in the available space. It will hold 36 degrees, no matter what. I can run it on coach batteries alone for three days, and it will run on shore power and the generator. I'ts my understanding that the expansion fridges are being gradually phased out. Dave W

This was my experience exactly. The Novakool maintains a very even temperature and I have yet to have a battery issue.