by Jack Bradshaw – Foretravel
If the absorber coils are more than 3 degrees out of level, the fluid will accumulate in the downhill turns. This will stop the gravity circulation of the fluid and block the upward recirculation of the hydrogen. The fluid level in the boiler also will be affected, as tilting in the direction of the boiler initially will flood the boiler, and tilting away from the boiler will starve it. A starved boiler will overheat, because of total or partial loss of circulation. If the refrigeration solution is grossly overheated, the sodium chromate in the solution could precipitate, forming small, hard particles capable of restricting or blocking small passages. This damage to the refrigeration solution is cumulative and permanent.
Most of us have heard of “burping” the refrigerator by turning it upside down. This procedure uses the fluid to backflush the system and, it is hoped, dislodge any debris that may be restricting circulation. Although this may work, most often the cure is only temporary, as the debris is still present, and the problem likely will recur.
How much are 3 degrees? For every 8 feet of length or width, 3 degrees equal 5 inches. Thus, an RV measuring 32 feet long and 8 feet wide would have to be 20 inches of level on one end or 5 inches Iowan one side to be 3 degrees off level. When half of the bubble of a level falls inside the black ring, this is approximately 1.5 degrees. Most likely, if the coach is level enough for your comfort, it is level enough for the refrigerator. However, when level, the absorber circulation will be at maximum efficiency.
What if I forget to turn off the refrigerator when the coach is severely out of level and then the refrigerator quits working? Cooling units made since 1983 have an improved style of boiler construction. A water jacket effect makes it difficult for the boiler temperature to elevate to the point of precipitating the sodium chromate. If the temperature stays in the average range, it will take several hours of critically off-level operation to cause damage. If this does happen, however, turn off the refrigerator and level the coach so all the fluid will return to the absorber vessel and boiler. Allow the cooling unit temperature to come down to the ambient temperature -this will probably take a couple of hours. Then turn the refrigerator back on and it should resume working.
Why do I get so much frost so quickly? Frost comes from moist air. If your freezer is generating a great deal of frost, it could be that an air leak is allowing this moist air to enter the refrigerator all the time, not just when the door is opened. The most likely suspect would be the door gasket. This can be corrected with a replacement gasket, which should be available for most models. A slight tear in the door gasket may be repaired using vinyl cement. If the gasket checks out okay, it is possible that air could be entering just behind the door seal because of a slight separation in the plastic inner liner from the metal cabinet frame. A small bead of clear silicone sealant around the perimeter of the liner will fix the problem. Make sure that all possible air leaks are sealed to prevent outside air entering the unit.
How often should the freezer be defrosted? There is no specific time interval. Remember, the freezer plate is absorbing heat. Moisture in the air will condense as frost on the subfreezing temperature of the freezer plate. The amount of moisture available is dependent on the humidity and frequency of opening the freezer door. Ice making also will contribute moisture for frost. As frost builds up on the freezer plate, the frost becomes an insulator of sorts. Heat must first penetrate the frost in order to get to the plate so it can be transferred to the absorber an out the roof vent. The more frost present, the less effective the heat transfer. If there is an inch of frost between your ice cream and the freezer plate, the temperature transfer will be much slower. In mild weather, this may not be as noticeable, but if the weather turns very hot it could affect the food temperature in the freezer. In warm weather, don’t let the frost accumulate to more than 1/4 inch.