Your 2-Way RV Fridge, How It Works and How to Maintain It.
A Typical 2-way RV Fridge
My RV Fridge Died.
I recently had to bite the bullet and have my RV Fridge replaced.
Oh, I tried everything I could to repair it, but to no avail. It had died and there was no resurrection for the thing.
I was not traveling for a while due to health problems and recently, everything improved and my wife and I I got back into what we love; traveling in an RV. This was after a couple of years of absence but we did get back to our favorite pastime; traveling the highways of America.
When we decided to get another Motorhome, after a lot of thought, we would purchased a nice used one, at a cheap price, and took our chances on there being problems that would need to be fixed later.
To make a long story short, we bought a really nice RETRO RIG, which was a 2001 Winnebago Adventurer with two slides. The interior was in excellent condition, and everything worked perfectly for us at the time of purchase.
But, recently, after over two thousand miles of driving ( over two long trips and three short ones) and a total of over twenty total days of camping, our Fridge started giving us problems. But more about that shortly.
Right now, let's look at how your 2-Way Fridge works.
A typical NorCold replacement Fridge
When I was traveling across the country in my Monaco RV, I had my fridge go bad and this was the replacement unit I purchased, It worked great for me.
2-Way and Conventional Fridge units in RV Campers
There are two distinct designs of Fridge units that are used in the different RV designs you will find in the USA.
2-Way Fridge Units
Nearly all of the 2-way Fridge units used in RV’s in America are made by either NorCold or by Dometic. And because of this, nearly all RV manufacturers design their RV cabinetry to accept either of these brands of these popular 2-way Fridge units.
Conventional Fridge units.
Conventional Fridge units are a lot cheaper than these 2-way units but, they do not operate on Propane so there is no way to keep it operating when there is no 110-VAC power. in the camper.
I know people who rarely travel in their RV and have replaced their old 2-Way Fridge with a conventional one, and they are quite happy with the change.
Several of them have even told me that it only took a couple of hours for a knowledgeable technician to take the old unit out and replace it with a conventional unit.
They had to “cap-off the Propane line and do a little cabinet work putting different molding around the Fridge; but the finished job looked good.
You should know that your larger new Motorhomes are now offering conventional Fridge units that are factory installed.
But, to get them to operate when there is no 110-VAC power the manufactures will usually have one or more 12-VDC batteries and an Inverter unit to provide 120VAC to the conventional Fridge while your RV is on the road and away from Campsites with power.
Having such a power system for a conventional Fridge does present it sown set of problems though, but I will not be covering this here.
Portable Ice Maker
When I knew I was going to be spending several months in the Arizona area, I purchased this model of ice maker to make sure I had plenty of ice. It was a great source of supplemental ice for us.
How your 2-Way Fridge Works
But before I go into my Fridge problems,let me explain some facts about how your typical RV 2-way Fridge operates.
It is called a 2-way Fridge because it is designed to operate on either Propane gas or on 120-VAC. These are the two sources of heating the Cooling Unit.
Yes, I said "heating the Cooling unit". You see, these Fridge units have a sealed gas section that, without getting into the technical details, when it is heated, the gases are compressed and as a result become cooler.
In fact, there are only three connections to your RV Fridge. It has a plug for 120-VAC, and a Propane Gas Line. And, many people are not aware of this but it also has a 12-VDC connection.
Knowing about this 12-VDC source, your COACH battery, is important because it is used by the control circuitry of the Fridge to manage the Cooling Process, while monitoring and setting the internal Fridge temperature, as desired by the operator.
Cooling using Heat
As I have said, you use heat in the Fridge Cooling section.
The Theory of Cooling a Gas
Imagine your Cooling unit being two metal tubes, one is a larger diameter than the other. Then you connect the two tubes end-to-end into a ring and fill them with a gas such as Freon. The gas used is selected because it expands dramatically when heated and becomes cooler when it is compressed.
If you heat a part of the larger tube, the gas in that area will try to expand and will physically move to an area of the tube that is at a lower pressure.
When the gas moves to the smaller tube, it is compressed and when it is compressed it will become cooler. So, if you placed the cooled part of the tube in an insulated box such as a Fridge, the air around the tube would cool down.
So, without going any further, for now, just accept the fact that your Fridge uses heat to expand the gas in the cooling unit which is then forced into a section referred to as a “compressor” and the gas is cooled down dramatically.
This cold gas is then forced through the coils inside your Fridge which will in turn chill the air inside the Fridge.
Fridge Construction for Optimum Cooling
The Fridge is essentially just an insulated box with all of its “operating parts” mounted onto the back of the unit. And, the Fridge itself, like any other device operates best within a certain range of exterior temperatures.
For instance, in a desert environment, the temperatures can get so high that your fridge will have a hard time compressing the internal cooling unit gases and keeping the inside of your fridge cool.
To help resolve this there are certain designed-in fixes that help expand the operating environment of your Fridge.
First of all, the back of the Fridge unit is accessible via two openings in the side of your RV. The lower opening is the service access and gives the user access to the controls and major replaceable parts of the fridge.
And the second opening is going to be in one of two places. It will either be an opening similar to the lower one on the RV but placed near the top of the RV.
But some RV’s do not have a second opening on the RV exterior wall, but rather they have a covered vent mounted on the roof of the RV directly above the area of the Fridge.
Regardless of the placement of the second opening, the purpose is to provide air flow for the Fridge from the bottom to the top.
In fact, you will find that most RV’s have at least one and sometimes two 12-VDC fans mounted between the top and bottom vents to force the air flow from the bottom to the top at a higher volume than regular convection would do.
These fans will dramatically improve your RV Fridge cooling capability in hot temperatures.
Cool with Gas or Electric
There are several reasons that so many RV’s have 2-way Fridge units in them.
First of all, you have the flexibility of keeping your food cold using standard 120-VAC which is available in campgrounds and campsites everywhere.
Secondly, while on the road, or while “rough camping” at a park, or just overnighting at a rest stop, or in a parking lot, your Fridge can be kept cold all of the time by using the Propane gas function.
This flexibility really allows campers to not only expand and enjoy their travel horizons but to eat well along the way.
NorCold Control Board
The Functioning Parts of a Fridge
A 2-way fridge does its job with five functional sections; the Control panel, the Control Circuit board, the Cooling Unit, and the Propane Gas section and then, of course, there is the Fridge/Freezer cabinet itself.
The Control panel is on the front of the Fridge and provides the operator with the necessary buttons to; turn it On, turn it Off, set the temperature, set it to automatic gas or electric mode switching or manual mode for each.
Control Circuit board
The control Circuit board is the heart of the RV 2-way Fridge. It controls and monitors all of the functions of the Fridge, and controls the power to the Cooling Unit, whether from 120VAC heating or from Propane heating.
It also senses that the Fridge is functioning properly and if there is a problem it has a standardized list of error codes for you to monitor.
The Propane section is a collection of mechanical parts that together, provide Propane powered heat to the Cooling Unit.
There are certain mechanical parts that can be replaced or serviced such as; gas orifice, heat stack (chimney), manual gas valve, electrical gas valve, and a few others, In reality, the whole propane section is very simple and easy to service yourself.
The Cooling unit of a 2-way Fridge is necessarily a self-contained unit, that is designed specifically to fit a specific Fridge manufacturers configuration.
As mentioned before, the Cooling unit takes the heat from the Gas heater or the Electric heaters and converts it to cooling for the inside of the Fridge.
One very important part of the Fridge is not actually a functional part but it is a passive part that must be in good condition.
It is essentially an insulated box that acts to maintain a cold environment for your food stored inside.
It must be maintained and used properly because your 2-way Fridge does not provide an excess amount of cooling capacity.
Door seals must be flexible and they must seal properly when the doors are closed. Even a slight air leak can dramatically reduce the cooling of your 2-way fridge so make sure the door seals fit properly.
And, of course, keep those doors closed if you want your food to stay cold.
Stay Open Fridge Door Latch
This is a great cheap tool that I use to keep my fridge door open when I store my RV, using it makes sure I don't get any mold growth in the fridge.
Major Parts Costs
The smaller parts of your 2-way Fridge, even one that is 10 or more years old, can be purchased relatively cheaply and replaced, it there are problems.
The major parts can be a little hard to find but there is a thriving industry of older fridge parts supply houses to shop with on the web, when necessary.
The parts of and RV fridge that cost the most and that go bad the most often though are;
Propane gas burner - This part can be picked up for as little as $30 to $75 if you shop around.
Propane gas electric valve - This part can be purchased for $50 or so.
Control Circuit Board - This part goes for $175 to $275 depending on the brand.
Cooling Unit - This part is the scary one.Due to its complexity it can run anywhere from $900 to as much as $1400. A bad cooling unit is one of the reasons most RV 2-way Fridge units get replaced with a new unit. If you shop around you can get a brand new Fridge installed for as little as $2000 to $3000 for a smaller one and even more for a 4-door unit.
Ice Maker - I didn’t mention there being an IceMaker in your Fridge but it such a great convenience that everyone I know has one.
One thing to note though, the IceMaker only runs on 120-VAC, so it does not run when you are on the road or when you are rough-camping. In fact you should make it a habit of lifting the lever on the IceMaker to turn it OFF when on the road to avoid there being water from the tray spilling all over the food in the Freezer.
And the cost? Well, IceMakers do wear out and need replacement every 5-8 years with average use. So, you need to know that a replacement IceMaker will cost you between $75 and $175.
In Summary, My Bad Fridge
Back to my situation. I tried repairing my Fridge when it quit on me. i did everything right,
First, I watched over a dozen YouTube videos on trouble-shooting an RV Fridge.
Then, I downloaded the appropriate owners manuals and schematics on my particular model of Fridge.
Once I figured I knew what I was doing, I pulled the panel and went to work.
I checked out that I had a good Propane flame (solid blue and steady) when in the Gas mode of operation.
I checked the two circuit board fuses, and even though they were good, I replaced them anyway.
I made sure that all wires were in good shape and none were broken nor were there and loose connectors.
I reset and re-cycled the control panel several times but the same trouble code appeared on the display; “NO CO” or No cooling.
And, finally, after an afternoon of crying into my beer, I accepted my fate and ordered a new Fridge from Camping World.
Just another day in the Life of a Camper, I guess?
Preventive Maintenance for your 2-Way Fridge
The 2-Way Fridge units used in today's Rvs are simple efficient designs that require very little maintenance.
But, there are some things you will need to check occasionally that can extend the life of your 2-Way Fridge.
Exterior Vents -
The exterior Fridge vents on the outside of your RV need to be kept clean to allow for free air flow to the functional equipment on the back of your Fridge. In fact, you will find that many of these vent covers will have a screen on the inside of them to keep insects out.
Spiders and other Insects -
This area, inside the vents, are favorite areas for Spiders, Mud-Daubers, and other insects to build their webs and nests. Remove the vent covers every month or so and clear these pests out so you will have clear air flow.
Fridge Drain Hose -
Also, you will see a drain hose, usually about 1/2-inch diameter in size sticking out of the lower Fridge Vent. This hose is a favorite site for some insects, and you should make sure you have the standard hose screen, available at Rv part stores, in place at the end of this hose to keep it from being blocked.
Heat Stack Ash -
On the back right side of your Fridge, you will find the area where the propane flame burns. Occasionally you should check that the flame is steady and the right color.
Also, you should tap o the cover above the flame and there will be small black particles of ash fall down onto the bottom of the Fridge, under the flame area. Clean this ash debris up every couple of months or so.
Fridge Control Box -
If you remove the lower vent cover and look inside you will see a black plastic box about 6-by-6 inches. This is the Control Circuit box.
You can remove the cover, if necessary, and check the 2-Amp fuse you will see on the circuit board. Otherwise there is little else you can check on the circuit board itself unless you are a trained technician.
Otherwise, you can just visually inspect the rear of the Fridge unit and look for burned or loose connections or wires.
There are other functional parts that you can check if you know what you are doing, but typically they will not give you problems very often.
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