How Do Propane (Gas Absorption) RV Refrigerators Work?

When you’re out camping off-grid, you don’t always have the luxury of shore power. That’s where propane RV refrigerators — also called gas absorption refrigerators — shine. They keep food cold and drinks icy even when you’re miles from the nearest outlet. But how exactly do they work without a compressor or moving parts? Let’s break it down. It's important to understand in order to keep it running like new.

The Science Behind Gas Absorption Cooling

Unlike residential fridges that use a compressor and refrigerant, RV propane fridges use a heat-driven chemical reaction to move heat out of the refrigerator box. The key players are:

• Ammonia (the refrigerant)

• Water (absorbs and releases ammonia)

• Hydrogen gas (balances pressure so ammonia can evaporate at low temps)

• Heat source (propane flame or 120V/12V electric element)

Here’s how it works step by step:

1. Heating the solution – A small propane flame (or electric heating element) heats a mix of ammonia and water inside a boiler.

2. Separation – The heat causes ammonia to vaporize and separate from the water.

3. Condensation – The hot ammonia gas moves through coils, releasing heat to the outside air and condensing back into a liquid.

4. Evaporation (cooling cycle) – In the evaporator, the liquid ammonia mixes with hydrogen gas. As the ammonia evaporates, it absorbs heat from inside the fridge box — cooling your food.

5. Absorption – The ammonia gas is absorbed back into the water solution, and the cycle repeats continuously as long as heat is applied.

In short: heat in → cooling out. That’s the magic of absorption refrigeration.

Why Propane RV Refrigerators Are Popular

• Boondocking friendly – They run for weeks on a single propane tank.

• Quiet operation – No compressor means no buzzing or cycling sounds.

• Durable – With no moving parts, they last for years when properly maintained.

Limitations to Watch Out For

• Level matters – Absorption fridges need to be fairly level (within 2–3 degrees) to circulate coolant properly. ALWAYS level out your coach when you get to a spot you plan to stay. Overheating the cooling unit from off-level operation is the number one cause of cooling unit failure.

• Slower cooling – They take longer to cool down compared to compressor fridges.

• Temperature sensitive – High ambient heat can reduce efficiency if ventilation isn’t adequate.

Maintenance Tips for Gas Absorption RV Fridges

• Keep vents clear for proper airflow.

• Check door seals regularly for leaks.

• Inspect burner and flue for soot buildup if running on propane.

• Install fans in the rear vent to improve cooling in hot weather.

Choosing the Right RV Refrigerator

Brands like Norcold and Dometic manufacture high-quality propane absorption refrigerators trusted by RVers for decades. Whether you’re replacing an old cooling unit, troubleshooting a flame issue, or upgrading to a newer model, having the right parts makes all the difference.

For genuine Norcold, Dometic, and Furrion refrigerator parts and support, visit RVFridgeGuys.com — the experts in RV refrigeration.

Final Thoughts from the Fridge Guys

A propane RV refrigerator might feel like magic, but it’s really just clever chemistry using heat to move heat. As long as you keep it level, ventilated, and well-maintained, it will keep your food safe and drinks cold wherever your adventures take you.

Make sure to keep some spare parts on hand so that you can get the most of your adventures and keep the maintenance to a minimum.

Top replacement parts to keep on hand BEFORE they fail:

Norcold Refrigerators

• Thermistor (this senses the temperature in the refrigerator and tells it when it turn on and off)
• Power board (this is the brains of the refrigerator and sends voltage where it needs to go)
• Optical board (this is the front controls of the refrigerator and is critical to get your refrigerator to turn on and off and change modes)
• AC heater (this is the component responsible for heating up the ammonia when running AC mode)
• Burner/ Orifice (this part produces the flame to boil ammonia on LP/ propane)

Dometic Refrigerators

• Thermistor (this senses the temperature in the refrigerator and tells it when it turn on and off)
• Power board (this is the brains of the refrigerator and sends voltage where it needs to go. Dometic often calls this part a "circuit board" but the meaning is the same)
• Optical board (this is the front controls of the refrigerator and is critical to get your refrigerator to turn on and off and change modes)
• AC heater (this is the component responsible for heating up the ammonia when running AC mode)