Dometic rooftop air conditioner · 1 model line
Dometic rooftop air conditioner code P4: Discharge tube overheat protection
Dometic documentation lists P4 as “Discharge tube overheat protection”.
What code P4 means by model
| Model line | What the manufacturer says | Source |
|---|---|---|
| Dometic FreshJet Series 4 / Series 7 (FJX) | The Dometic FreshJet FJX operating manual lists P4 as discharge tube overheat protection. | Dometic FreshJet Series 4, FreshJet Series 7 Operating Manual |
What you can safely check
- Record P4, selected mode, setpoint, outdoor conditions, and how long the unit had been running.
- Stop FreshJet operation from normal controls if the code returns.
- Keep visible air intake openings, air nozzles, and ventilation grilles clear before service.
Stop and call a technician for
- Discharge tube temperature protection, sealed-system condition, refrigerant-circuit work, fans, sensors, and rooftop compartment diagnosis should be handled by authorized Dometic service or qualified RV HVAC personnel.
Disconnect power before any FreshJet service. Refrigerant-circuit, sealed-system, sensor, fan, drive, electrical protection, roof seal, and internal component work is for authorized Dometic service or qualified RV HVAC personnel.
Write this down before you call
- Full FreshJet model and serial number from the data label
- Wall control or display code photo
- Shore-power or campsite voltage context and active loads
- Recent service history and prior recurring codes
Other codes on Dometic FreshJet Series 4 / Series 7 air conditioners
Full table: Dometic FreshJet Series 4 / Series 7 air conditioners
- P0 Over temperature or over current on the IPM module
- P1 Under voltage protection
- P2 Unit AC over-current protection
- P3 Overvoltage protection
- P5 Evaporator coil protection in cooling mode
- P6 Condenser coil protection in cooling mode
- P7 Evaporator coil protection in heating mode
- P9 Compressor drive abnormal or compressor does not start
- E0 Communication failure
- E1 Room temperature sensor fault
- E2 Evaporator coil temperature sensor fault
- E3 Condenser coil temperature sensor fault
- E7 Outdoor temperature sensor failure
- E8 Discharge tube temperature sensor failure
- E9 Compressor drive or IPM module fault
- EA Current sensor fault
- EE Outdoor EEPROM fault
- EL LIN-BUS/CI-BUS communication failure
Related troubleshooting guides
- Dometic FreshJet FJX constantly switches itself off
- Dometic FreshJet FJX low air output
- Dometic FreshJet FJX not cooling within temperature limits
- Dometic FreshJet FJX not heating within temperature limits
- Dometic FreshJet FJX voltage protection and campsite power
- Dometic FreshJet FJX water enters the vehicle
- RV rooftop air conditioner is not cooling enough