How to Check Ammonia Level in an RV Fridge

Modern RVs are loaded with amenities which is one reason why they are so popular. One amenity that makes them a permanent abode for many is their refrigerator. RV refrigerators aren’t just practical but also quite eco-friendly since they use ammonia as a refrigerant. However, ammonia is also prone to leaking which can lead to health hazards. With RV usage increasing with each passing day, it is important to have some degree of know-how to address issues that may arise from your RV’s refrigerator.

Getting the Maximum From Your RV Fridge

An ammonia refrigerant-based fridge like those in an RV has some prerequisites to function properly. Firstly, there should be adequate ventilation on all sides. This essentially means clearance on all sides and both the bottom and the top. Secondly, the fridge must stand on a completely level surface. The irregular surface can disrupt the flow of refrigerant leading to poor cooling. Last but not least, is the heating source. RV fridges are equipped with heaters (AC heater or a 12VDC heater, sometimes both). These heaters heat the coils that make the coolant flow through the tubes. Make sure that these heating sources are warm enough for adequate cooling.

Ensuring all the prerequisites mentioned above are vital for a perfect RV fridge. However, it is also necessary to give some time (8-10 hours) to allow for adequate cooling once the refrigerator has been turned on. In case the refrigerator still doesn’t get to its normal temperature (35-41 Fahrenheit), it is time to look for signs of one of the main culprits – ammonia leakage. The following passages would help you figure out if there’s any seepage of ammonia from your RV fridge.

Identifying Ammonia Leakage

Ammonia is a colorless gas, but it exudes a strong smell that is instantly detected by a human nose. To be clearer, ammonia generally smells like sweat, urine, or a fish. If you detect such an odor from your RV refrigerator, then ammonia leakage has possibly occurred. Another good indicator of ammonia leakage is the presence of yellowish/greenish powder around the exterior insulation pack or sometimes on the walls of the refrigerator.

Many refrigerators tend to gurgle after a short while when they are switched on. This gurgling phenomenon also happens to be indicative of ammonia leakage. For the fourth and final sign of ammonia leakage, you would have to get a bit creative. Using your hands, check if the rear of the fridge is getting disproportionately hotter compared to the cooling inside. If yes, then you may have to deal with ammonia leakage.

Other telltale signs of ammonia leakage include broken or damaged coils/tubing through which ammonia circulates throughout the system. Since ammonia can cause corrosion, therefore, any unusually rusted surface is a good pointer toward ammonia seepage.

After identifying ammonia leakage, it is time to measure the ammonia level in your RV fridge. This is so you know how low the refrigerant gas is and how much is needed to bring the fridge back to its proper functioning level. There are a variety of ways to check ammonia levels. All methods are described in detail below:

How to Check Ammonia Level in an RV Refrigerator?


Ammonia Detector

The most precise way of gauging ammonia levels in an RV refrigerator is to use an ammonia detector. The detector checks the level of ammonia to relay whether your fridge is working properly or not. Ammonia detectors come in a variety of capacities, though a low concentration range detector will be ideally suited for an RV fridge. Audio, visual or haptic feedback lets you know whether or not ammonia is leaking.

To use an ammonia sensor, place it either near the compressor, coils, or above the compressor. After holding it for a few seconds you will be able to get a reading. If the reading is above 0PPM (Parts per million) then there is a leak. If the reading exceeds 100PPM, then a hazardous level of ammonia is present in the surrounding. Immediate action must be taken under such circumstances.


Phenolphthalein Test

As the name suggests, the phenolphthalein test has its roots in chemistry. Thankfully, it isn’t as complex as chemistry tends to get. Also, it is quite cheap in that you will only need phenolphthalein paper. On the flip side, you won’t get a precise reading like an ammonia detector.

To conduct this test, first, you will need to slightly damp the strip using distilled or at least boiled water before holding it near or above the compressor. The moisture would allow better absorption of ammonia which will lead to a more accurate result. Upon detecting ammonia, the paper will turn itself from white to pink. The darker the pink color is, the more the leakage of ammonia is there.


Litmus Paper

Phenolphthalein test and litmus paper test work in an identical way. Both have the same pros and cons, meaning you can use one or another without any compromise. However, where a phenolphthalein paper turns pink upon getting in contact with ammonia, a litmus paper turns blue. A strong/dark blue color indicates a heavy presence or leak of ammonia gas. If the color remains unchanged, then there is no leakage.


Sulfur Sticks

Both the sulfur stick and phenolphthalein test are very identical in that they both are qualitative and use a chemical reaction to detect whether or not there’s an ammonia leak. Sulfur is used in matching sticks, so it is clear to deduce that the sulfur sticks are match sticks themselves. Light up a sulfur stick and bring it close to the compressor of the refrigerator or inside the box. Monitor the color of the flame during the whole process as it will indicate the presence of ammonia. White smoke from the stick is indicative of an ammonia leak.


Cloth Detection Method

A detection cloth is a special kind of cloth that has been infused with bromothymol blue. It isn’t as easily available, but it can be purchased online or from some hardware stores. To use this cloth to detect ammonia leakage, place it close to the fridge storage area and wait for 30-40 minutes.

After 30-40 minutes, take a look at the cloth. If it has turned from blue to green, then there is a high amount of ammonia leakage. If the cloth is still blue, then there is no leakage. Worthy to mention here is that this method should only be kept as a last option. Reasons for this recommendation are the relative unavailability of detection cloth, long detection time, and a qualitative result.


Dealing with the Aftermath

It is advised to take precautionary measures immediately in case you have detected ammonia leakage. Some of the measures mentioned below will prove to be very handy for you under such an incident:

  • Open the windows and doors for the ammonia to escape. Ammonia has a high rate of diffusion, and it can quickly spread inside your entire RV. Letting it ventilate through all the possible points is a good strategy.
  • Many times leak emerges from the cooling unit. In such a case, you will need to replace it. However, replacing a cooling unit is a job best left to a professional technician. It is also worth noting that replacing the cooling unit comes at a significant price.·  If you are unable to get hold of a technician and the RV is the only abode for you, then try neutralizing the smell of ammonia by spraying vinegar. It absorbs ammonia gas and within a few hours, you will hopefully be able to relax comfortably in your RV.


The safe level of ammonia for your fridge will depend on the model of fridge that you have. Check your owner's manual or contact the manufacturer to find out what the safe level is for your particular fridge.

If the ammonia level in your fridge is too high, you will need to ventilate the area and call a professional to service your fridge. Do not try to fix the problem yourself, as you could be seriously injured.

If the ammonia level in your fridge is too low, you will need to add more ammonia. This can be done by mixing ammonia and water in a 1:1 ratio and adding it to the fridge. Again, do not try to fix the problem yourself, as you could be seriously injured.

Ammonia refrigerators are a great option for RVs, but they can be dangerous if not used properly. Be sure to check the ammonia level before using your fridge, and never try to service it yourself. If you have any questions or concerns, please contact a professional.

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Ever since I was a kid, I've been fascinated by travel. I inherited this passion from my parents. Since my college years and to this day, I have had a passion for traveling in a motorhome. I am here to share my experiences with you.

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