Old vs. new gas fridge performance

mcneon · 01-25-2004, 08:20 PM

My '74 Argosy motorhome has its original Dometic fridge - model RM66, I think. It cools okay initially but in warm weather won't hold the cold temperature. On a relatively warm weekend (80-90 degrees) I'm lucky if it stays below 50 degrees inside, and that's with the flame burning high most of the time. The gasket looks fine, and I replaced the missing freezer door long ago. Performance is about the same on gas or AC.

Is it safe to assume that my Dometic has permanently lost some of its cooling efficiency? If so, what caused the loss? Will a new gas absorption fridge be noticeably better at maintaining its cool? Should I expect a new fridge to hold 40 degrees or below in 90+ weather for several days?

I'm trying to decide between a new Dometic and a DC compressor model like the ones from Tundra (www.tundra.cc). With 245 A-H of house batteries, 3 amps for the Tundra isn't a big deal. It'd be worth it, too, if it'll stay cool in really warm weather.

Bob McKeown
Nashville

ke4pk · 01-25-2004, 08:33 PM

The later model gas/electric refrigerators, beginning in the mid 70's will keep their temp properly on either gas or electric.

They will make a frozen brick of a gallon of milk, on gas, if you turn them up to high.

RivetED · 01-25-2004, 09:44 PM

Our current 3.0 Dometic 3-way is set between 2 & 3 to keep it from freezing bottled water overnight! That is also in the summer in Texas on either gas (propane) or A/C, only use D/C on-the-road.

**overlander64** · 01-25-2004, 10:36 PM

Greetings Bob!

The two-year-old Dometic 3-Way RV refrigerator in my '64 Overlander is one of my favorite up-grade purchases. It is remarkable in its performance - - and it operates as well on 12-volt as it does on any other setting - - in fact it has only been used on LP less than five hours since it was installed. It has always kept the refrigerator compartment between 35 and 39 degrees.

My Argosy still has its original Dometic. It still will maintain consistent temperature while camped, but it is VERY sensitive to level and the coach needs to be nearing absolute level to get best performance from the refrigerator. Based on my experience with the Overlander, I won't spend much on overhauling it when it fails - - I really much prefer the 3-Way Refrigerator in my '64 Overlander.

Good luck with your refrigerator dilemma.

Kevin

Safari Tim · 01-25-2004, 11:14 PM

Bob,

I have heard of people adding a small DC fan to blow up from the bottom of the fridge coils up to keep the circuilation going.

This helps them cool better. You may try it as an experiment. Put a switch on it and it it works you could add a small thermostat to it to have it automatic.

Let us know if you try it.

A side note, I had my new Dometic fridge working in 100 degree heat and it had to be turned up all the way to keep the temp down. But it did work.

These things do not appear to operate like a home style fridge.

For example, in the mountains the setting that keep the fridge just right during the day froze the orange juice during the night into slush.

You think for the price of these things they would operate better than that.

**Stefrobrts** · 01-25-2004, 11:33 PM

Hey Kevin, How's your new fridge do powerwise? Does it really suck the batteries down when you're running it on 12v? We still have the original fridge in our trailer, and I'm going to add a fan and see if that help this summer, but last summer it struggled to keep things in the 'safe' zone on the thermometer, even cranked all the way up. It's LP only.

So if the fridge runs on 12v then can you run it that way while travelling, instead of dealing with the LP issues (like stopping before you gas up to turn it off and start it up after you leave the station)? I'm still a little nervous about driving with the propane on.

Navigator · 01-26-2004, 06:00 AM

If your ammonia refrig is not running better than your freon type, than you are either not level, or low on refrigerant. The Renken cycle of ammonia is FAR superior to freon, thats why ammonia is used in commercial freezer lockers.
Dick

87MH · 01-26-2004, 06:07 AM

I installed a cheapie small fan inside the outside fridge access hatch, angled it to blow "up". There should already be a receptacle there if your fridge is set up to run on AC. The fan only draws 60 watts, and is on whenever I'm hooked to shore power. It did make a difference in warm weather performance - after I got the circuit board problems in the Dometic ironed out.

**overlander64** · 01-26-2004, 07:47 AM

Greetings Stephanie!

Quote:

How's your new fridge do powerwise? Does it really suck the batteries down when you're running it on 12v?

The refrigerator operates on 12-volt at all times while traveling and much of the time while dry camped. At the time of the refrigerator install, my dealer ran some extra-heavy wiring for the refrigerator 12-volt circuit, and added a second house battery. Even when operating on the batteries exclusively for three days, I wasn't quite out of charge on day three, but that was maxxing out the batteries (this was during the first partial season of two months with the refrigerator). During the first full season with the refrigerator, I had three solar panels installed along with an inverter, charge manager, and third battery (upgraded to three gell-cell batteris at this time as well). The results have been fantastic.

Since my Minuet sees use primarily as a weekend and short trip trailer, when it is upgraded to a new Dometic 3-Way Refrigerator I will go with two gell cell batteries with a typical converter-charger arrangement as it wouldn't benefit greatly from solar panels for it use patterns.

Quote:

So if the fridge runs on 12v then can you run it that way while travelling, instead of dealing with the LP issues (like stopping before you gas up to turn it off and start it up after you leave the station)?

You have stated my number one reason for going with the Dometic 3-Way RV refrigerator. It has always amazed me that Airstream doesn't install them in their new coaches - - it was a standard feature in the 1980 Nomad that I purchased new, and it is where I learned how wonderful the 3-way Refrigerator is for traveling - - the one in my '80 Nomad was about the only thing on the coach that I would rate as a GREAT feature. Until my Minuet needs a new refrigerator, I am operating its refrigerator while camped a just the verge of freezing everything in the refrigerator so that I can turn the LP off while underway - - if it is extremely warm, I carry an ice chest for cold senesitive items.

Kevin