I have been in the refrigeration industry for twenty-six years. For over 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.
Below is an article published in the RV Technician in the summer
of 2003.
Absorption refrigeration was developed by Michael Faraday in 1824. While absorption refrigeration systems can be found in industrial and commercial situations, by far the most used application is in recreation vehicles, motor homes, trailers, houseboats, Amish Communities and other remote areas. This is due to the unit being small and quiet with few moving parts-the perfect refrigerator for the road and remote areas. Natural gas, LP gas, kerosene, steam, or an electric heating element may be used for the heat source, allowing the user to operate the unit safely and with ease.
The liquid and gases used in absorption refrigeration are not harmful to our environment. Ammonia is used for fertilizer on crops. It is economical to those of us doing recharging because when it is drained from the cooling unit, it can be saved and reused later. Hydrogen is the only chemical lost from an absorption refrigerator. Small quantities of it will get released into the atmosphere where it originally came from.
TROUBLESHOOTING THE COOLING UNIT CORE
Our most common complaint from customers is insufficient cooling. Some customers have already taken their refrigerator to a dealer or RV Service Center before coming to us. Because of their lack of education, the cooling unit was condemned and the customer was told to throw it away and buy a new refrigerator. The first step in troubleshooting is to determine whether you have a control or a cooling unit problem. When diagnosing follow these easy procedures.
PROCEDURE 1: Inspect the cooling unit for any yellow coloring. Yellowing is caused by sodium chromate, a rust inhibitor, and is usually found in the boiler pack area (although yellowing can occur elsewhere). Yellowing indicates a leak in that area.
PROCEDURE 2: Open refrigerator door and check for ammonia odor. If order is present, this indicates a leak in lower evaporator section. If refrigerator is a two-door model, open freezer compartment and check for ammonia odor there as well. If detected, this indicates a leak in the upper section of evaporator coil.
PROCEDURE 3: Probe Inspection
NOTE: Do not troubleshoot cooling unit using 12-volt connection or LP gas. 110VAC ensures accurate results.
Bypass all controls by connecting 110VAC directly to heat element. This allows testing of cooling unit without interference from other controls. Ensure heat element is required wattage for unit being serviced by probing heat element with amp probe.
Volts x Amps = Watts Example: 110VAC x 2.25A = 247.5 W. (A 10% cushion either way is allowable.)
If within two minutes, a rapid boiling, often referred to as a gurgling noise, is noted coming from boiler section, unit contains a leak. This cooling unit needs to be reconditioned.
PROCEDURE 4: If no rapid boil is noted, level the refrigerator and allow unit to run for approximately one hour. After such time some warming should be noted in bottom absorber coil, cooling observed in freezer compartment, and considerable warming present at top of steam line, just before condenser. It these conditions are present, place a thermometer in refrigerator compartment and allow to run over night. Check refrigerator temperature next day. Regardless of ambient temperature, thermometer in refrigerator should read below 32°F.
The next day if the refrigerator temperature reads below 32°F we have proven the cooling unit is working properly. There is a control causing the insufficient cooling and needs to be repaired or replaced. If the refrigerator temperature is above 32°F the cooling unit is causing the insufficient cooling and needs to be reconditioned.
Normal refrigeration is considered 38° to 40° F in the box; while 0° F is the target in the freezing compartment (all temperatures are nominal). When hooking direct to the 110VAC heating element you are running the unit “wide open” with no controls. This is why lower temperatures are acceptable.
NOTE: In the heat of summer, when ambient temperature is 90°F or greater, the refrigerator temperature may only read in the high 20’s. In cooler seasons, when temperature drops significantly, that same refrigerator’s temperature may read 5°F or cooler. Ambient temperature plays a big part in these types of cooling units.
OLD TIME MYTHS & REMEDIES
Complaint: Insufficient Cooling
Many absorption refrigeration users have been advised because of the lack of education, to try the following remedies. Roll the refrigerator, hit it with a hammer, or ride down a bumpy road with the unit in the bed of a truck, or flip it upside down for a day and then return it to its upright position. When these remedies failed to produce the desired result, the unit was brought to us for proper diagnosis and repair.
If the refrigerator did work after this remedy in all probability, the cooling unit was never bad. Either dirt was in the gas line or orifice, or there was a bad connection in the wiring or one of the controls. Throwing, dropping, torching and hammering on the unit could be very dangerous unless no charge exists in the unit, in which case a leak is present. None of these remedies will repair a leak.
Remember it’s all about EDUCATION. It’s easy when you know how. For further education on RV refrigerators contact Ford RV Refrigeration, 1746 Big Bear Hwy. Benton, KY 42025, PH# 270-354-9239 or e-mail us at info@rvrefrigeration.com or www.rvrefrigeration.com
Article published in RV Technician- Summer 2003
