I have been in the refrigeration industry for twenty-six years. The last twenty years I have specialized in the reconditioning of RV Refrigerators. During this time I have written and published the first “how to” manual on the subject of reconditioning RV Refrigerator Cooling Units. This manual is the “The Ford Procedures”. In addition, I have designed and manufacture the specialized tools needed to do the reconditioning. To date, I have trained nearly 300 individuals across the United States and Canada in the Ford Procedures. In the upcoming issues of RV Technician, I will be covering different aspects of reconditioning RV Refrigerators.
Properly Diagnosing RV Refrigerators
In the RV Technician, summer 2003 publication, my article covered troubleshooting the cooling unit core. I would like to recap one section of that article.
Procedure 3, Probe Inspection.
NOTE: Do not troubleshoot cooling unit using 12V connection or LP gas. 110 VAC insures accurate results.
Bypass all controls by connecting 110VAC directly to the heat element. This allows testing of the cooling unit without interference from other controls. Insure that the heat element is the required wattage of the unit being serviced by probing the heat element with an amp probe.
A Helpful Hint
When checking the wattage of a heat element with an amp probe, you are allowed a 10% fluctuation either way. Example: If the required wattage is 250W, and the amp reads anywhere from 225-275W, the heat element will work adequately for that refrigerator. If the amp reading is lower than or exceeds the 10% fluctuation, replace the heat element with a new heat element. NOTE: Don’t take for granted that a new one will be the correct wattage. Check it with an amp probe.
Plugged Cooling Unit
My students and customers have often inquired about a plugged cooling unit. On the older model refrigerators, when the refrigerator is operating in an unleveled position, it is supplying unsatisfactory cooling to the refrigerator compartment. This allows the liquid portion of the chemicals in the cooling unit to pick up debris that is lying on the bottom of the cooling unit. (Debris finds it’s way into the unit during factory assembly). The old style boiler tubes have a small inside diameter. This was a contributing factor to a plugged cooling unit. Depending on how much debris is in the cooling unit and how long the refrigerator runs out of level plays a part in how long it runs before it plugs. During detailed testing I found some cooling units would plug in just over one hour, while others would run with insufficient cooling for up to five days before plugging.
When a heat source, (gas or electric), is applied to the cooling unit boiler, it perks like a coffeepot. At the strongest point of perking, the debris is picked up and carried up the boiler tube. Eventually, because of its size and weight, it becomes too heavy to be carried up the full length of the boiler tube. It falls, collects in one area, and forms a blockage. If left running in this condition, the cooling unit overheats and the blockage is baked until it is as hard as a rock. From about 1980 to 1990, I repaired boiler tubes in approximately 30% of the cooling units that I reconditioned. This was the only place I ever found a cooling unit to be plugged. In the case of a plugged boiler tube, follow “The Ford Procedures”.
Troubleshooting
The following conditions would indicate that boiler tube is plugged:
After unit has run for approximately one hour:
- No rapid boil
- No temperature at the top of the steamline just before condenser
- No temperature in the freezer
- Little or no temperature in the bottom absorber coil
- Steamline is extremely hot where it exits the boiler pack.
Reconditioning
The first option is always to try to unplug the boiler tube, then clean and flush the entire cooling unit. If cleaning the boiler tube is unsuccessful, the next option would be to remove the plugged boiler tube and replace it with new tubing. It is critical to pay close attention to the tube length, the inside diameter of the tube, and the size, shape, bends, and turns of the tube. The replacement boiler tube needs to be an exact replacement. Heat element sleeves and flue tubes also have to be removed from the old boiler tube and rewelded on to the new boiler tube. Again, this requires an exact replacement.
The good news is that the refrigerator manufacturers have been using a new style of boiler for some time. The plugged cooling unit will only be found on very old models. My compliments to the refrigerator manufacturers.
Believe It Or Not
Many absorption refrigeration users have, on the advice of the misinformed, tried different remedies to overcome problems with their refrigerators. I have acquired, through my customers, a list of these myths and remedies, of which I will share with you in my articles.
***NOTE: No offense is intended to anyone in the areas indicated in my myths and remedies. I use these areas because the information came from someone that resides in that area. This is only to be viewed with humor, although these remedies were actually reported to me by individuals that tried them.
The Kentucky Confusion Contusion
When a customer from Kentucky took his absorption refrigerator to someone who was uneducated in this field, he was told to put the refrigerator in the back of his pickup truck and drive as fast as he could along a bumpy road.
This, of course, did not solve the problem, so the gentleman brought the refrigerator to us. We reconditioned the cooling unit on his absorption refrigerator. When we were finished, it worked like a new one.
If you have any myths and remedies, send them to Ford RV Refrigeration. We would like to share them with our readers.
Remember, it’s all about EDUCATION. It’s easy when you know how. For further education on RV refrigerators read future issues of the #1 RV Tech magazine, RV Technician.
Coming soon: More troubleshooting hints and old time myths and remedies.
Source: The Ford Procedures Manual by Roger D. Ford courtesy of Ford RV Refrigeration. For more information, go to www.rvrefrigeration.com or contact me at 1746 Big Bear Hwy, Benton, KY 42025. 270-354-9239 or email info@rvrefrigeration.com.
Article published in RV Technician- Fall 2004
