Dometic 3-Way Fridge not working right?

[TomPiper]

Hey Folks,
2011 Bambi Sport 22FB with original Dometic Fridge
The cooling system itself must be doing fine because when we are on shore power, it gets very cold and freezes things in the freezer.

But on 12V and propane, it seems to have stopped really cooling beyond slightly better than room temperature. Does this make sense?

Complicating things is that I've got some strange things happening on the propane side (e.g. with tank valve totally closed, I can still get propane to my range top and to my water heater (and presumably the fridge since no red light goes on). And on the 12V side, while I've got two brand new 6V batteries in series plus solar (and good battery readings at all times) I guess one never knows how much power it's truly delivering?

I appreciate any thoughts on where the problem may be here. Thanks.
Tom

[pcskier]

Make sure the burner tube and exhaust on are not clogged from spider webs or mud daubers, etc.

[ITSNO60]

What model is the fridge? You certainly don't want to run it on 12 volts while parked, it will use a ton of power. The 12 volt is really intended to maintain an already cold fridge while under way, not to use while parked, that's what a compressor fridge is for. Also the 12 volt wiring leaves something to be desired and often is way undersized resulting in a big voltage drop which means less watts for the heating element and poor absorber performance.
As far as the propane, it is normal to still have propane for quite some time after shutting the valve off, how long did you wait? For me it takes a good 5-6 minutes with both stove burners on high to use up what is in the lines after shutting the valve off.
I recently had an issue with my Dometic (RML8555) not cooling as well on propane and it turned out I had a accumulation of oil that had settled in a low point right after the regulator causing my WC (water column) to be only 10" with nothing on. The fridge requires 11" of WC and the spec for the regulator is that it should maintain 11" while the water heater, fridge and all stove burners are on. It's quite simple to make a water tube manometer with some plastic tubing, a board , colored water and a ruler or you can just buy an electronic one on Amazon for $40. There is a test port on the back of the fridge, you'll need a 1/8" NPT plug with a 1/4" test nipple in it. Once I replaced my regulator and the wet lines my fridge on propane went from 39F to 29F. (I now have to turn down the setting, something I never could do before). I also installed a drip leg to prevent this from happening again.
I also found out regulators have a date code on them and in general should be replaced after about 10 years.
In summary when your propane mode is working poorly you should look at the cleanliness of the tube, the burner and the orifice as mentioned by Peter and then the gas pressure by way of a manometer. When those things are in order there is no reason it shouldn't cool.

PS if you have a BBQ hookup you can make a quick connect for your manometer for easy gas pressure testing.

[waninae39]

Be sure the trailer is level in both planes. If not the gas cooling process may work.

As well, most cases of gas fridge fires occurred when the trailer was not level and ran on gas.

12v and 110ac don't care, gas does

[LBelle]

i am sure it is "not the same" but we recently (right after some routine work at the dealer) had problems with our Dometic fridge: when we were getting ready to head out, i.e. in our front yard, it would work on shore power but not with the propane. Frustrating, especially since "they" just checked things out! But we knew we had hookups at the campsite so ignored it...low and behold it was fine once we were there.
But now I think I will follow ITSNO60's recommended steps and see if there might be a problem.

[ITSNO60]

I've been a DIY all my life, first it was to save money but soon I discovered there is a lot of truth in the old adage "If you want it done right, do it yourself" and in recent times it is more true than ever before. It's also very satisfying, in a kind of survivalist way I guess.

[AirGT65]

Our three way Dometic fridge was running erratically for a year or so. I finally replaced the two circuit boards to fix it. Works fine now. One board is in the back, and the other circuit board Is part of the front top control panel. Both must be replaced together on the 3 way models. Contact Dometic help line for info on the correct part number. I had to get mine from an independent source. Mine cost around $120.
Before you do this, check for spider webs and blockages in the propane line.
Good luck.
By the way, I run the fridge on propane when on the road. Works fine. No need to use 12 volts when traveling, in my opinion.

[Vlamgat]

Originally Posted by AirGT65

By the way, I run the fridge on propane when on the road. Works fine. No need to use 12 volts when traveling, in my opinion.

Maybe but why is it expressly verboten in the OMs and by many States?

Before the days of semi conductors, that was the only way a fridge could be run while on the road yet even then most OEMs warned against it?

[TomPiper]

Thanks All. All great input. I'm going to find a video on how to clean out the burner tube. But it may be that it's overdue for a more professional servicing anyway.

And I appreciate input on efficacy of running off the 12V system.

Does anyone know the rough lifespan of these refrigerators. We've used this one extensively for 13 years and we are hoping to head to Alaska next year. I wonder if I should retire it before it retires itself?