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Airwave503 · 08-17-2016, 12:35 PM

I'm new to 3 way fridges and just got the Dometic RM2354. I've taken 2 trips so far. In both cases I prepped the fridge by running it on AC shore power for 1-2 days before leaving and made sure it was cold with food in it before departing. I ran it on gas while towing. When we got camp I made sure the burner was going and the top of the fridge door was warm indicating to me that it was running. On both trips the fridge slowly lost it's cool to the point that I had to put everything in the cooler and give up. On both trips, temps were in the 90's with lot's of direct sun on the driver side of the trailer where the unit it installed. On the second trip I tried opening the lower vent door to see if that would help, it didn't.

Now back home, I've had the fridge on gas for 48 hours in lower temps and more shade. It is cooling but definitely not as robust as when in AC mode. I don't think it should matter but the only other difference is that I have it in straight gas mode, not Auto/Gas mode.

My question is, should I expect the fridge to work as well on gas as AC? How about DC which I haven't tested yet (I have a very good AGM battery).

Also, was the high heat likely the culprit on my trips? Thanks in advance.
--Jason

**Hans627** · 08-17-2016, 01:42 PM

Sorry I don't have enough knowledge to answer your question but would like to jump on the thread to learn.

dwightdi · 08-17-2016, 02:03 PM

Sounds like you might be low on refrigerant gas. Some RV places have the gauges required to check the pressures. Gas type refrigerators (whether operating on AC or gas) have limited capacity to cool. High temps are definitely a problem. How cold was the freezer compartment?

Dexterpix · 08-17-2016, 02:06 PM

I have not experienced any difference in the cooling capabilities as I believe the system operates on the same principle regardless of fuel type. The difference I believe is the heating element (flame or electric) You might check to see if the fridge is still "burning" once you arrive at your destination. I have had the burned go out during transport (only once in high cross winds). Does the fridge show any error code. If the propane line is not purged the fridge might not light in the allotted time and will go into safe mode and stop drawing propane. If the flame goes out the safety will shut the supply of propane off at the burner and even though you are "on" propane you are not running (no flame burning in the combustion chamber). you should not only feel the heat of the system working, but you should hear the sound of the burner running.

The high temp will make it work harder so you might see a few degrees higher than normal during the day and it will drop back down over night. I tend to see 34-35 over night 36-37 during the day.

Best of luck
Joe D

ijustlee · 08-17-2016, 02:06 PM

The older gas fridges cooled better on gas than on electric because the boiler ran hotter but not sure about the newer ones. Getting the heat out from in back of the fridge is very important! Refrigerators pump the heat from the food out to the back of the fridge so it has to go somewhere, and gas fridges have to also dispose of the extra heat that circulates the refrigerant. The gas fridge also needs to be properly leveled because the refrigerant flows by gravity to do the cooling and it is a very weak force powering the circulation.

AWCHIEF · 08-17-2016, 02:11 PM

Interesting experience. I think my fridge runs about the same temps on gas and AC. Ambient temps and direct sun seem to be the main determining factors of my units effeciency. I installed an adjustable thermostat to better compensate for ambient temperature changes. I recently completed a Blue Ridge Parkway extended boondocking trip where I spent over three weeks running the fridge 100% on propane. I actually had to turn the thermostat up a couple of times to prevent freezing in the fridge compartment when parked in full shade.

Jammer · 08-17-2016, 02:59 PM

Quote:

Originally Posted by Airwave503

On both trips the fridge slowly lost it's cool to the point that I had to put everything in the cooler and give up. On both trips, temps were in the 90's with lot's of direct sun on the driver side of the trailer where the unit it installed.

Hi Airwave

The situation you describe is a difficult one for the fridge. My fridge will struggle to keep up in 90 degree temperatures in the sun, but can still maintain mid 50s usually.

I would suggest checking things that could affect overall performance, like door seals, since you may just have a situation where the fridge is working marginally in the driveway and the sun and heat, combined with the door opening as you remove items, are too much for it to keep up with.

Quote:

Now back home, I've had the fridge on gas for 48 hours in lower temps and more shade. It is cooling but definitely not as robust as when in AC mode. I don't think it should matter but the only other difference is that I have it in straight gas mode, not Auto/Gas mode.

In general the performance should be the same on AC and gas. If there really is a problem specific to gas operation, you might have a burner that is dirty or out of adjustment, or a flue blockage.

Quote:

How about DC which I haven't tested yet (I have a very good AGM battery).

The performance on DC should be the same provided that your DC power distribution system is delivering at least 12.0 volts to the fridge, or ideally, a little more than that. 3 way fridges suffer a poor reputation for their performance on 12v because they draw 10-15 amps, and too often the DC wiring produces enough of a voltage drop that there's only 10 or 11 volts being delivered. There will be little or no cooling taking place at these voltages.

Another fact to consider is that these fridges work best when level. Some are more sensitive to out-of-level conditions than others, depending on the design of the cooling unit.

HowieE · 08-17-2016, 03:41 PM

There are several things to check.

First look at the gas flame. It should appear uniform in shape and blueish in color. If t is not shaped well there may be something in the burner tube, spiders and stink bugs are common. If it is yellowish again it may be bugs or the air intake is not adjusted to give a nice color. If they all check out OK the chimney may need cleaning or the baffle may have collapsed, not that likely because the chimney functions with electric also.

How are your other gas items? Good color and full flame? That will check out the gas system.

TG Twinkie · 08-17-2016, 06:41 PM

It should perform better on gas. Since the BTU content is higher.
Some owners have installed fans at the back of the refer with good results in removing the heat.
I would check the gas pressure just to make sure it is correct.

CRH · 08-17-2016, 06:47 PM

I think mine cools about the same on gas or electric. On the lowest setting, it will freeze some foods.

Airwave503 · 08-18-2016, 09:38 AM

So coming up on 72 hours running in gas mode. A can of soda I put in the freeze is feels cold, but not frozen. The can in the main compartment is just a bit cooler then if it was sitting on the counter top.

Thanks for all the input:

"Sounds like you might be low on refrigerant gas"
Would this just affect gas mode? Cause it works great in AC mode.

"You might check to see if the fridge is still "burning" once you arrive at your destination. You should not only feel the heat of the system working, but you should hear the sound of the burner running."
Yes the flame has been brining the whole time nice and blue about a half inch wide, picture attached. But I don't hear any burning or running noise coming from the fridge. It's quiet.

"If there really is a problem specific to gas operation, you might have a burner that is dirty or out of adjustment, or a flue blockage."
It's brand new, I'll try and check the flue.

I've been level in all tests and the on demand water heater and kitchen stove top were working fine. On AC at level 5 the highest setting we had things start to freeze in the main compartment after several hours. After 3 days on gas the main compartment is barely cool and the freezer is a good fridge temp. I may test DC mode next.

CRH · 08-18-2016, 10:06 AM

You need to check your gas pressure.

Jammer · 08-18-2016, 10:11 AM

If it's brand new, you should be able to get it fixed under warranty. Dometic has service centers everywhere, and I have had good results with their warranty service.

The performance you describe isn't normal.

HowieE · 08-18-2016, 10:30 AM

The only difference between the 2 systems is the heat source. The thermostat, heat exchange system, the chimney, and the control board are all the same.

The problem has got to be in your gas heat source. You have checked the color of the flame and the flame shape does not have blank areas across it. That leaves the height of the flame, effecting total BTU input. Older units had pressure gauges and one could see the delivered pressure, spec 11 pounds water pressure. If your unit has a pressure regulator at the frig gas valve you might try a slight adjustment on it while watching the flame height. Give t a little and take a temperature reading an hour later.

crispyboy · 08-18-2016, 11:05 AM

I would check the the propane system pressure with a manometer.
Another simple check would also be to remove and clean the gas orifice. There could have been some dirt/debris entered during assembly.
A third item which I would check is the installation of the refrigerator itself. The PO of our trailer had a new refrigerator installed but overall it always struggled to cool properly and consistently. Through an installation manual I found that there should be no more than 3/4" of space between the back of the refrigerator and the back wall, 0" of clearance on the sides and top. I pulled the refrigerator, built a false wall in the back and reinsulated around the other sides.
The refrigerator works well in all conditions now.

CDONA · 08-18-2016, 11:10 AM

When did they stop making 3 way refers? I remember them back in the 70's, but new stuff is only 2 way, because of the big electrical hit running the 12 v heating element.
It can't be a ammonia issue for it runs on 110v. So it must be a controller module, burner fuel mixture or a propane supply issue.

Jim A · 08-18-2016, 12:35 PM

I had our 2012 FC down in Uvalde Texas for the past two weeks (before the rains) with outside temps in the day on the order of 102 and lows in the upper 70's, sitting in full Sun. Running on gas, freezer temps stayed in the 7 to 10F range and fridge temp was usually in the mid 30's in the daytime and 32ish at 6AM. Of course, putting a couple trays of water to make ice cubes put the freezer temps into the 20's for awhile. (temps monitored with remote reading temp sensors). That's sort of typical for our summertime outings. With two AC's running in different combinations, the inside temperatures were on the order of upper 70's to very low 80's depending on what was running when.

HowieE · 08-18-2016, 01:55 PM

Misprint. I think it is 11 in. water column.

crispyboy · 08-18-2016, 02:15 PM

Quote:

Originally Posted by HowieE

Misprint. I think it is 11 in. water column.

Yep - should maintain 11" WC when you have several appliances running or more than 11" wc and less than 13" wc static condition.

gecko · 08-18-2016, 02:38 PM

We had similar issues in our 2009 28' International. Definitely ran cooler on AC than on propane.

It was recommended that we add a refrigerator chimney fan for very hot days, but this did not help. Then we were told that that one fan was not enough, and we went to three fans. this definitely helped, particularly on the very hot days.

But while traveling on hot days, we found that the gas was blowing out (expecially with crosswinds.) To fix this, a baffle plate of aluminum was added between the outside vent and the burner. So far, in 15,000 miles of travel, this has done the trick, and it has only blown out once.

We are now in the habit of checking every time we stop. The outside digital thermo on the Dometic does not necessarily give the correct inside temp when the gas burner blows out. You must turn off the reefer and then turn back on, and all of a sudden you will get a correct, much higher reading, if the burner had been blown out. Checking each time you stop will let you know how often it's blowing out, as well as re-starting to give it a chance to work while you're going down the road.

If you still have problems after following the suggestions here, definitely bring the coach to your dealer and ask that Dometic take care of it. Or take it to your dealer straightaway and explain the problem and ask them to fix it for you.