June 1, 2008

TT #54 Back to Basics RV Refrigerators

By: Rob Lowe

Technical Tips #54 


Back to Basics: RV Refrigerators

Does anyone remember the old style RV refrigerators which were a giant leap from the ice boxes we had in our pop-up campers? RV Refrigerators have changed a lot from the small basic models available twenty-five years ago. Newer models are divided into two and four door versions to allow the freezer or fridge to be accessed without lowering the temperature in the other section. All of the doors contain a lot more adjustable shelving and many of the commonly accessed items are able to be accommodated in the doors. Typical interior sizes range from 8 to 12 cubic feet, or about one half the size of a home refrigerator. Modern models are semi-defrosting versions with many containing built-in ice makers and water dispensers. These automatic ice makers spare you from the task of filling ice cube trays with water and emptying them a few hours later.

From a technical perspective, RV refrigerators have changed as well. You do not need to manually light the gas burner to begin operation. Most no longer have a 12 Volt heater to allow operation on batteries, however all require 12 Volt battery power to operate. These microprocessor controlled refrigerators maintain the temperature in both the freezer and the refrigerator portion electronically using built in sensors and electronic circuit boards to monitor operation. An electronic display allows easy variation of the temperature and modes with many switching operating modes automatically depending upon which power sources are available. Insulation quality and quantity has improved dramatically so that the refrigerator does not need to be left on while travelling. It will maintain safe temperatures, keeping food fresh, for six to eight hours as long as the doors remain closed. Some can operate off a 1500-2000 watt inverter for short periods of time and these models can safely be left operating while travelling.

The most common reason that these refrigerators fail to operate is poor electrical connections in the control circuitry. We regularly find that one intermittent connection leads to replacement of the circuit board. Dometic, one of the well known makers of RV refrigerators reports that 80% of the circuit boards returned to it during their three year warranty are not defective. This would indicate that the problems consumers were experiencing with their refrigerators were likely caused by faulty connections not a defective control circuit board. Replacing the board "fixed" the refrigerator however the problem was not correctly diagnosed.

We recommend using Corrosion Block® on all connections. Just one drop on each connection terminal of the circuit board should prevent any corrosion. In addition many of the junction type connections can be treated with a drop of this chemical. Just apply the application tube to the joint between the two sections and pump a drop or two from the tin. The chemical's ability to "wick up" inside the connection coating the bare metal and arresting any corrosion will allow the refrigerator to continue to operate for years without problems. Make it a habit to recoat these connections every couple of years to maintain optimum protection. In the past we would also have suggested regular cleaning of the gas burner chimney base however improvements to the metal used for these chimneys have greatly reduced the corrosion of the metal and almost eliminated the need for blowing out the gas runner tube and vacuuming out debris from the burner.


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