A refrigerator that has not been cleaned with an ammonia-based cleaner, yet still gives off a clear ammonia smell, is probably in need of repair. Small, portable refrigerators and older domestic units frequently contain ammonia-based coolants; consequently, a sharp ammonia smell from the fridge often indicates a coolant leak.
Ammonia Smell From the Fridge
Long before the development of modern coolants, ammonia, or NH3, was routinely used to keep refrigerators cool, allowing homeowners to store fresh foods for short periods. While ammonia refrigeration is not as common these days, it is still used in miniature refrigerators or for portable units found in campers and RVs. An ammonia smell in your RV typically is due to a refrigeration leak.
This characteristically pungent aroma is one of the main advantages to using ammonia as a coolant, enabling owners to detect even the slightest leak almost instantaneously. A rapid response often reduces the cost and complication of the repairs necessary to keep the unit in working order.
Advantages and Disadvantages
In addition to being readily detectable by the human nose, ammonia is also relatively cheap to produce and fairly efficient. Refrigerators that use ammonia do not use the standard compression/expansion cycles favored by most modern refrigerators; they function on temperature fluctuations, allowing them to operate on limited amounts of electricity.
On the downside, ammonia tends to be corrosive and is combustible when mixed with oxygen; therefore, in most domestic refrigerators, ammonia has been replaced with less toxic, less flammable chlorofluorocarbons or hydrofluorocarbons, more commonly known as CFCs and HFCs. Ammonia does have an advantage over CFCs and HFCs in that it is less damaging to the environment, and breaks down to nitrogen in just a few days.
Ammonia and Safety
Ammonia vapors are highly irritating to the skin, eyes and respiratory tract. To prevent an accumulation of fumes, once an ammonia leak has been detected, open all doors and windows to increase the ventilation in the room. Should irritation occur, leave the room immediately, and rinse the affected areas with copious amounts of cold water.
Because ammonia is caustic, this is not a repair that should be undertaken by unskilled DIY enthusiasts.
Getting Professional Service
Aside from vintage refrigerators, ammonia-based coolant systems are typically found only in large industrial applications and special-purpose fridges for niche applications. Because of this, even if your specific refrigerator is a vintage domestic model, you may have better results if you turn to an RV or cottage outfitter for service.
Most ammonia-based fridges are compact electric models or full-height propane powered models, used in RVs, cottages and off-grid installations. If your local RV dealers don't keep a technician on staff to deal with refrigeration issues, it's very likely they can at least recommend the nearest service provider with experience and expertise in ammonia-cooled systems.
Removing the Odor
Should an ammonia smell linger once the unit has been repaired, the aroma can be easily removed by filling a few shallow dishes with fresh coffee grounds and leaving them in the unit for 24 hours. The grounds are covered with tiny pores that readily absorb the odors in the air around them.
Lisa Parris is a writer and former features editor of "The Caldwell County News." Her work has also appeared in the "Journal of Comparative Parasitology," "The Monterey County Herald" and "The Richmond Daily News." In 2012, Parris was honored with awards from the Missouri Press Association for best feature story, best feature series and best humor series.