Tips For Troubleshooting Dometic 3 Way Fridge Problems

Is your Dometic 3-way fridge not cooling properly? Dealing with a fridge that isn't cooling your food and drinks can quickly put a damper on your camping trip. But before you call for expensive repairs, there are several troubleshooting tips you can try to diagnose and fix the issue yourself.

We'll go over how these popular RV absorption refrigerators work, break down the most likely issues, and give you step-by-step instructions for getting your fridge back up and running.

Understanding How Dometic 3-Way Fridges Operate

Unlike most household refrigerators, RV absorption fridges don't use compressors. Instead, they rely on a chemical process to create a cooling effect. This process can utilize three different energy sources - propane gas, 120V AC electricity, or 12V DC from your RV's battery.

Here's a quick overview of how absorption cooling works in a Dometic fridge:

• The boiler heats up a mixture of hydrogen gas and ammonia.
• The ammonia evaporates and travels to the condenser where it cools back into a liquid.
• The liquid ammonia goes to the evaporator where it absorbs heat and evaporates again.
• This cycle of evaporation, cooling, and re-evaporation pulls heat out and creates the chilling effect inside the fridge.

Key components of the system include the boiler, condenser, evaporator, absorber, and piping connecting them. The absorption process can use electricity from a heating element or combustion from an LP gas flame.

Common Dometic Fridge Issues

When trouble strikes your Dometic fridge, there are a few common problems to look for:

• Not cooling sufficiently - Food isn't getting cold enough. The fridge may cool somewhat just not down to proper temperatures.
• Not getting cold at all - The fridge interior is the same temperature as the outside. There is no cooling happening.
• Intermittent cooling - The fridge works sometimes but not others. Temperatures fluctuate.
• Strange noises - Hums, buzzes or gurgling sounds coming from the fridge.
• High temperature alarm - The alarm sounds indicating the fridge is too warm.
• Error codes - The display panel flashes odd numbers and letters like "noFL" or "noAC".

Finding the root cause of these refrigeration issues requires a logical, step-by-step diagnosis starting with the basics.

Checking the Basics First

Before diving into advanced troubleshooting, its wise to check some basic things first:

• Is it level? - Absorption fridges need to be as close to perfectly level as possible. Use a bubble level to check.
• Are vents blocked? - Ensure vents aren't obstructed by anything preventing airflow.
• Is there ventilation? - Fridges need ample air circulation. Don't cram other items too closely around it.
• Does the door seal? - A faulty door gasket can let out the cold. Make sure the seal is intact.
• Is the burner lit? - On gas mode, verify the burner is igniting and producing a flame.
• Is the power source correct? - Make sure the fridge is plugged in or connected to the battery.

Taking these simple preliminary steps can reveal issues affecting cooling before you dig deeper.

Troubleshooting by Energy Source

The next area to troubleshoot is the energy source. Since absorption fridges use gas, 120V AC or 12V DC, problems could exist with any of those systems.

Gas Troubleshooting

If your Dometic fridge isn't cooling on propane mode, try these gas troubleshooting steps:

• Inspect the burner, lines, flue and orifice for blockages preventing gas flow.
• Check the gas valve operation - tap it with a screwdriver handle while activated.
• Test the thermistor continuity using a multimeter to see if it's functioning.

Electric Troubleshooting

For issues running the fridge electrically, focus your diagnosis here:

• Check all fuses and wiring related to the fridge 120V supply.
• Test the heating element using an ohmmeter. It should show continuity.

DC Troubleshooting

To troubleshoot the 12V DC operation, try these steps:

• Inspect all 12V fuses and connections between fridge and RV battery.
• Check DC voltage at the control board input terminals while powered.
• Test the thermocouple continuity using a multimeter.

Advanced Diagnostic Techniques

If the basics check out, yet the fridge still isn't cooling right, it's time to dig deeper:

• Use service mode on the control panel to read any error codes present.
• Test input and output voltages at the control board with a multimeter.
• Check the thermistor resistance with an ohmmeter. Compare to spec.
• Check the igniter resistance. It should be 40-70 ohms.
• Inspect the flue and orifice for soot buildup indicating combustion issues.

These advanced troubleshooting techniques require electrical testing tools and technical skill. Have these tasks done by a professional if you're uncomfortable probing circuits.

Refrigerant System Concerns

Occasionally an issue exists within the sealed refrigerant system itself:

• Low refrigerant charge - Not enough hydrogen/ammonia mixture due to leaks.
• Refrigerant leaks - Cracks or failed seals releasing the mixture.
• Blocked evaporator/condenser - Dirt or debris restricting refrigerant flow.

Repairing these refrigerant problems requires removing the fridge, evacuating the system, locating leaks, replacing parts, resealing, recharging, and reinstalling. Refrigerant work should be left to certified technicians due to the expertise required.

Carrying Out Repairs

Once you've diagnosed the issue, here are some common Dometic fridge repairs:

• Cleaning - Removing debris/soot from burners, vents, flues.
• Replacing thermistor - Installing new thermistor if faulty.
• Replacing thermocouple - Swapping out bad thermocouple.
• New burner - Fitting an OEM replacement burner.
• Sealing cabinet - Resealing leaks in cabinet insulation.
• Door gasket - Removing and replacing a worn out door gasket.
• Control board - Installing new control board if original is damaged.

Take proper safety precautions if disconnecting any propane lines or dealing with refrigerant. Wear protective equipment to avoid burns or exposure to hazardous gases.