Refrigerator not cooling

[judyallen]

Hi, first trip out in a used 1999 Dodge Freedom. The refrigator got cold in the freezer, but the cooler fins in the refrig. did not get frost on them. The food I put in freezer was already froze, and it remained frozen. The food I put below in refrig. was cold when I put it in, but I had to get ice to keep it cold during our trip. Can anyone tell me why the fins did not get cold. Refrig., was not over packed.Its a Domentic refrig. model rn2333 Thanks Judy

[renrut]

Is your fridge a 3 way or 2 way? Mine runs on propane and 120vac. I had problems with it running on AC and found the element was burned out on the heater. I got a new one and the fridge was working fine. On another occasion, the thermostat was broken and I needed to replace it.

If you can try the fridge on propane and see if it works, it would narrow down the problem. If it works on propane, you may have a problem with the heater or thermostat like I did. If it doesn't work on propane and AC, it may be out of freon and that would take a lot more to fix.

Just to note, my fridge has 2 thermostats, one for AC and one for propane. If you fridge only has one thermostat, it might be harder to check.

[judyallen]

You know what? I left in on gas all night, and this morning, it was very cold, and the fin's were starting to frost up. I am thinking I just didn't get it cold enough before we went on our trip. So next time, I will starting cooling things down the night before. I am used to a larger unit, and they cool quicker. Plus, in our larger motorhome, the refri. switched itself auto. I think they call it "live and learn". Thank you for your reply.

[judyallen]

I now know alot more about my refrigerator than I did on our last trip. It is a 3-way, gas, 12 volt and ac. Ok, the gas works well, and the AC, seems to cool sufficiently, and I am not sure about the 12 volt. The fins frost up on gas, and the freezer seems to be ok, as the foods stay frozen, but I don't think the refrigerator stays cold enough, while we are traveling. I was wondering if freon could be the problem. Thanks for any comments.

[markopolo]

The coolant is most likely to be ammonia in a 3-way fridge. You will smell it if it is leaking. I don't think you can "top it up". You can buy the boiler and tubing kit for most fridges or you can replace the fridge.

I think what you are experiencing could very well be normal. The best performance on my 3-way fridge (and 2-way fridges) has always been when on propane. 2nd best is when on electric and worst when on battery. My understanding is that, when on battery, the fridge will do it's best to maintain the temperature in the fridge. It doesn't really "cool" when on battery.

Measure your fridge temperature.

I always use a indoor / outdoor wireless thermometer in my RV fridges. You can get them for $10 to $15 at Walmart. The "outside" transmitter goes inside the fridge and the receiver part sits on the counter or is mounted on a wall in your RV. Ideal refrigerator temperature is between 35 and 38 degrees F (1.7 to 3.3 degrees C). With a wireless indoor / outdoor thermometer you'll always know what your fridge temp is and can adjust your fridge temperature control accordingly.

Once you have confirmed that your fridge is not cooling properly then the first part I would look at is the thermistor.

There should be a finned aluminum 'heat sink' in the inside back part of your fridge. The thermistor is attached to a wire and located in a long white plastic clip attached to the last aluminum fin on the left. Slide the white clip (thermistor) up to cool more, down to cool less. Some Dometic fridges actually have a label inside with those instructions. I'd really consider replacing the thermistor if adjusting it by sliding doesn't help. It is a $15 to $20 part.

I had a fridge that was too cold and had to replace the thermistor: http://www.classbforum.com/phpBB2/vi...9&t=595&p=1584

[Mike]

marko, I think you're right about 12VDC performance on a 3-way Dometic.
Ours has always been marginal on batteies. We've tried it a couple of times,
just to see if it was working, and we were convinced it wasn't. However
it didn't seem to lose any ground.
It's never actually cooled down more than a degree or two on battery.
As far as maintaining temperature, it probably does that more by insulating
the contents from the outside air temp, than actually providing cooler internal
temps.

[judyallen]

Thank you for your advice, and I think you are right. I always had a larger Rv, that would switch itself to gas whenever the electric shut off. We are learning alot about our class b and it is by trial and error. I will definitely purchase a inside/outside thermometer Thanks again

[renrut]

Just to differentiate between AC and battery; they use the same coil heater on the fridge (at least the one I have and from what a dealer told me). The AC uses the entire coil therefore creating more heat to work the fridge. The DC uses a wire tapped off the coil. Needless to say, it is 1/10th the size of the AC coil (AC is 120volts and the DC is 12ish). DC will not create very much heat because the coil is so small. This is why fridges running on DC do not work very well.

I would make sure the seal is good on the door and make sure the door is closing properly. Any small leak would allow the fridge to loose temperature especially if on DC. Another thing to check is where the heater coil is. It should be basically in an air tight place within the gas tube. If air can get into that area, the heater would quickly cool if wind and air was moving around it. I realize this may be a hard thing to find but it's just an idea.

[judyallen]

Thanks so much for all your help, I know you are right and now I will just relax, and have more fun. Believe it or not, that fridge was making me a little crazy. and I will check the seal....Thanks. Now can you explain to me about the inverter/converter...what does it do?

[Mike]

Mostly they "invert" or "convert" 12V DC power to 110-120V AC or vice versa to run your electric "stuff".
Depending on what type of power your appliance needs, and which source you want to use,
you might be able to just plug it in and away you go, or you might need an extra piece of equipment.

My van has 2 types of electric power source outlets. Some look like cigarette lighter sockets, and I also
have a couple that look like regular household wall outlets.

My cig-lighter type outlets are located up front at the dashboard, and in the rear entertainment
cabinet near the bed.

The ones up front run off the vehicle 12VDC battery (the one that starts your engine) and can
run things that need 12VDC power. I sometimes use them with a 12VDC to 110VAC mini-inverter to
recharge stuff while we're driving. Low draw only. Like camera batteries or cell phone charging.
I never use the vehicle battery outlets to charge stuff when the engine isn't running. That way
I don't discharge the vehicle battery too much that I can't get the van started.
A dead vehicle battery is mostly a bad thing.

The rear ones in the e-unit draw from the house or coach batteries. The coach batteries are separated
from the vehicle battery by a battery separator or isolator, so that you can discharge them without
draining your vehicle battery. I enable them via a "battery enable" switch at my monitor panel.
They can run things which require 12VDC power. For example,
I have a small dirt sucker vacuum cleaner that uses 12VDC power and has a cigarette lighter style plug,
so I can plug it into one of the e-unit cigarette lighter outlets, enable the coach batteries, and use it
to clean up little spills and messes.
I also use 2 slightly larger draw 12VDC to 110VAC mini-inverters to run my laptop and LCD TV. I have a 100W
and a 150W mini-inverter for these 2 uses. Since most of my electric "stuff" uses well below 50W
of power each, the 2 mini-inverters are more than enough to handle their draw.
You can plug the mini-inverters into a cigarette lighter type plug, and then plug (into them) a 110VAC type
2 or 3 pronged plug from the appliance. Very useful, for me, at least. They get the most use in my van.
They can be purchased at Canadian Tire, or Best Buy, or Radio Shack, or most major electronics stores.

Some folks on here have either bought vans with much larger inverters already installed or added them
later to run larger draw items like their Microwave ovens or electric heaters, etc..
The coach batteries will (slowly, we hope) drain with use, and can be recharged at least 3 different ways,
but that's another topic. 4 ways, if you add a solar charging system. Again, another topic.

The ones that look like house outlets, are 110-120V AC output when the van is plugged into
shore power at a campground, or with an adapter into my house's outside 110V outlet (using
the big black cable with the funny plug), or when I'm running my 2800W Onan on board generator.
The shore current 110VAC just passes through the inverter in the van and comes out at the van outlets,
or, the generator power is inverted/converted to 110VAC and comes out at the van outlets as 110VAC.
Anything with a 2 or 3 pronged plug which uses 110VAC power can run when plugged into them.
I'm going to start making coffee with a drip maker that uses 900W so I'll be running my
generator for 10 minutes while the coffee maker is plugged in to one of the house outlets. Also,
my microwave is plugged into a house type outlet, and I'd have to be on shore power, or running my
generator to make popcorn in it. It draws more watts than the mini-inverters can provide.
Also, my A/C unit needs shore power or the generator running to work properly because of it's
larger current draw.

So, does that make any sense at all?
I'm not an expert, but that's my view of the world as it relates to class B vans.
If it doesn't rain tomorrow, I'll try to add a couple of pics of my usual setup.
Oh, the coach batteries can be charged by the engine/alternator combo when the engine is running,
by plugging the van into shore power with the "battery enable" switch enabled, or
by running the generator for a period of time. In a 2002 Roadtrek, anyway.
You can move slightly farther "off the grid" by adding a solar battery charge system, but you'll
have to ask VernM or markopolo for more info about that.

[Mike]

Pics and a further dialogue about this subject can be found in the "Inverter or Generator" thread
in the General section on here.
viewtopic.php?f=9&t=1367