Dometic Duo-Therm air conditioner: keeps tripping the breaker. Unit is 4 years old. 57915-331 Everytime we use it; it cools the camper just fine but out of the blue it trips the breaker and won't work. Sometimes it cycles off and on, off and on. This unit is in a travel trailer, with a ducted system. suggestions ?

First clean the condensor with air blower or water pump and clean the filters.If the same problem persists there is a choke up in the refrigeration piping, cut from the discharge side and suction side flush the system with nitrogen, replace the filter drier and choked capillary if it is a capillary system, brace back the discharge and suction piping to the compressor again, leak test with nitrogen, evacuate the system charge refrigerant and start the system.

Just had the same problem. Turned out to be the run capacitor, about $15 incl. shipping. Real easy to fix. just be sure to unplug the main power for safety. Hardest part was putting up the ladder to get on the roof. On mine, there is 2 capacitors, a start capacitor and the run capacitor. The run capacitor was the bigger of the two. Be sure to match up the numbers on the capacitor when buying the new one. The dual run capacitor on mine was 45+5 uF, 370V, 50/60Hz, these are the numbers you would want to match up. While your up ther you may want to check to be sure the fan is spinning freely and also clean the condenser with air or water.
Good Luck!

On the above response, you better have some reasonable knowledge on A/C units, this is not a job for the inexperienced. Just saying