Refrigerator Buying and Troubleshooting Guide - Online RV Supply

Refrigerator Buying and Troubleshooting Guide

This guide should help you learn more about your RV refrigerator, how to troubleshoot it, and ultimately how to replace or purchase a new one. RV fridges are quite a bit different from the usual residential appliances that we have at home.
But like most things, with a little curiosity and the willingness to learn more, you will be able to make informed decisions on one of the main appliances in your RV.
Here is what we'll answer:
  • How an RV fridge works and how it differs from a home fridge
  • How to troubleshoot a problem refrigerator
  • What to look for when buying a fridge
  • How to install a new fridge
  • We'll also give you some tips and tricks to help make the most of it!

How An RV Fridge Works

It's helpful to know the difference between a residential fridge and an RV refrigerator. They work very differently and that will make a difference in your purchasing decisions.

Unlike your home fridge or even your RV air conditioning units, your RV fridge does NOT use a compressor to move coolant through the system. Instead, the system has many less moving parts and is a bit more robust.

However, the basic ideas of refrigerator theory are still relevant. A chemical mixture is moved past metal coils that either absorb heat or release it. This is called an absorption refrigerator.

Here’s how an absorption refrigerator works:

RV Refrigerator diagram
Goran tek-en, CC BY-SA 4.0, via Wikimedia Commons

 

Now that might look a bit complicated, but basically the process is simple. A heat source warms a combination of ammonia, hydrogen gas, and water. As the mixture warms, the heat causes some of the chemicals to evaporate. As this vapor passes into an area that is meant to be cooled, condensation forms and cools the inside of the fridge. The reverse happens outside and the heat is moved.

There are two ways that the fridge can create the heat that starts this whole process, electric heating elements or LP gas. Usually a fridge is able to automatically switch between the two modes depending on if you are plugged in, running the generator, or using propane. However, not all have this feature, so be sure to check.

Models that have this functionality are categorized into two catagories: 2-Way and 3-Way. The most common type is a 2-Way system using AC power or LP gas, while a 3-Way system adds the ability to run the fridge on 12V battery power. That way when you are underway, your food and drinks are kept nice and cool.

    Now that we know the basics on how a fridge cools and the fuel sources that allow it to do so, lets get started troubleshooting a problem RV Refrigerator.

    RV Refrigerator Troubleshooting

    Here is a quick trouble shooting guide. Depending on your issue you might start with making sure your rubber door seals are good and the door is closing snugly.
    Small air leaks around the door can really cause the inside of a fridge to vary in temperature so its important to make sure you have a nice seal.
    Most problems with RV refrigerators fall into 3 broad catagories:
    1. Thermistor or temperature sensor issues
    2. Heating element problems, or
    3. Control board or electrical connection issues

    THERMISTORS

    Norcold 629409 Refrigerator Thermistor Replacement Assembly

    Let's take a look at these in order and help you understand how problems can occur and how to address the most common issues. Since there are few moving parts on RV fridges its pretty simple.
    First, a RV thermistor is a small piece of material that changes how easily electricity can flow through it, based on the temperature of the material. Since the level of electrical resistance can be easily measured by your control board, it can also determine the temperature in the refrigerator core. Think of this as a simple thermometer like device that just reports the relative temp back to the "brain" of the system. Often attached to the back or fins of the interior of your fridge, this sensor is a vital part of the system.
    Thermistors are rather inexpensive and are often easily replaced via simple wiring harness connections. It's a good place to start trouble shooting, since an improper temperature reading can make a fridge do odd things or simply not work at all.
    Multimeter
    To check the existing thermistor, simply remove it and attach a multimeter to the ends. Consult your Owners Manual for the proper range of readings. If it's out of range, you'll need a new one before moving on.

    Heating Elements

    Since your RV refrigerator needs some source of heat to apply to the chemicals in the system, it's important to verify that they are functional. Usually accessed from the back of the appliance or even through an outside panel, there are the two ways we mentioned earlier: Electric and LP Gas.

    First, check the condition of the exposed wiring. Look for frayed or damaged wires that might be leading to an electrical short, and check for corrosion at the connection points. Usually this is fine, but it's worth taking a close look.

    Carefully feel the exposed piping on the back of your fridge, if its warm then things might be working fine in the heating parts. If not, set your fridge to AC power and see if the electrical heating element warms up.  If that looks ok, check to see if there is a port to view into the LP flue system. Switch the unit to LP settings and see if you can get a flame and that the flue is unobstructed. If you feel there isn;t gas flowing, it might be a solenoid issue. These can get dirty, or they might not be getting the correct signal from the main issue of RV failure: the control board.

    Control Boards

    If all your other checks look ok, then we are left with the usual suspect when it comes to RV refrigerator issues: the control board. This somewhat delicate piece of electrical circuitry controls the entire system and is the "brain" of your system. This little piece of electronics controls the gas flow solenoid, the ignition, and the electrical heating elements, as well as any fans or additional features. Diagnosing one is a bit technical, so calling your Manufacturers support line might be an option. Generally the only way to fix a control board issue is to simply replace the entire board.

    That about does it for fridge troubleshooting, but sometimes you'll just be interested in an entirely new appliance.

     

    Buying a New Refrigerator

    When looking to purchase a new refrigerator you'll need to keep a few things in mind:
    • The physical size of the unit and the opening in which it needs to fit
    • The capacity of the interior for those items you want to keep cold
    • The options and features of the unit
    • And finally, the price ranges

    Exterior Size

    Different RVs have different sized refrigerators and if you aren't intending to build a custom cabinet to mount one in, you'll need to be aware of the existing opening and the size of your replacement unit. Each manufacturer has a reference chart to help you with selecting the right replacement unit for your old fridge.

    Interior Capacity

    Your fridge can only hold so much, so make your decision on the capacity based on your intended usage. Keep in mind that not all RV refrigerators that are the same physical size on the outside, have the same physical interior space!

    Double check to make sure you are getting the right size for your needs.

    Options and Features

    Ice makers, double doors, freezer compartments, vegetable crisper and other options vary between model number and manufacturer. Make sure to plan ahead for your use cases and choose the options that matter the most to you.

    Price Range

    Costs of RV refrigerators range from approximately $1000 to $3500 dollars with some models being higher than that. However, these are durable appliances made of stainless steel and heavy duty materials to withstand the demands of life on the go. A durable refrigerator should last you years of trouble free use and enhance your time spent RVing.

    Refrigerator Installation

    Once you've made a decision about which new refrigerator to purchase, all that's left is installation. If you are comfortable working with LP gas lines and electrical wires, you can install one yourself. Assuming no alterations to your cabinetry, it is a matter of unplugging and unhooking the existing unit and replacing these connections on your new modern fridge. Check your owners manuals for model specific installation instructions and always keep safety in mind.

    Enjoy your new fridge!

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