RV Refrigerator Repair
The absorption style RV refridgerator is a low maintenance
device, but there are some things that you can do to help it do it's job. The most important thing is to keep it
clean and prevent any obstructions in the venting system.
When operating in the LPG gas mode, the products of
combustion are removed by the flue. After a period of time, soot and rust particles accumulate on the inside
surface of the flue. Road vibrations will loosen these deposits and they crumble and fall to
the burner below. The finer particles fall into the burner itself, while the larger pieces remain on top of the
burner and cause problems with the flame sensor. As the fine particles build up inside the burner, they alter the
burners volume and shape. This results in an improper flame and affects the heat output of the burner. The flame
may look normal, but it is not producing the required amount of heat to operate the cooling unit.
It is hard to tell by looking at the flame - a proper flame
and a slightly reduced flame will look the same. There is no adjustment that you can make.
The orifice should be soaked in alcohol (no, NOT
Vodka!) and allowed to air dry. Replace the orifice if you suspect it is partially blocked after cleaning it.
Blow out the burner with compressed air. Check the gas pressure at the refrigerator gas pressure test port using
a manometer. You can build your own manometer for a few dollars (see manometer) for details and instructions. If the gas
pressure is not 11" w.c., you may have a thermostat problem or a main regulator problem.
The BTU input (meaning the amount of heat) is about the
same for the propane flame or the AC heating element by design. This is because the cooling unit is fabricated to
process a certain amount of heat to make the 'cool'. It does not matter to the cooling unit whether this heat comes
from a flame or an electric heating element.The heat source, meaning the propane flame or the electrical heating
element, is used to "elevate" the ammonia/water mixture to the top of the cooling unit. There after it is gravity
and the PHYSICAL change of state of the chemicals that does the rest of the cooling work.
The air flow across the back of the refrigerator is also
gravity controlled - hot air rises and flows out the roof vent. Cooler air is drawn in through the bottom or side
vent to replace this rising air.
Any assistance, especially in HOT weather, will help with this heat
dissipation. A fan to move the air need not be a large one to effect a higher efficiency. Also, the addition of
sheet metal baffles to direct the moving air through the evaporator fins can be very effective.
Use a mirror to look up into the back of the refrigerator
compartment. There should be a maximum of one inch clearance between the evaporator coils and the facing wall. If
the clearance is more than this then your refrigerator will benefit by the addition of baffles. It may be necessary
to remove the refrigerator to install the baffles, but that is not a hard task to do and may result in a very much
improved cooling efficiency. This rising air collects heat from the evaporator fins as it passes by, thus removing
heat from the cooling unit.
If your unit cools better/faster on one source as compared to
the other, there is most likely a deficiency with the other system.