Dometic Air Conditioner: “P4 / P5 / P6 / P7”
warning RV air conditioner error codes
What it means
Refrigerant-circuit temperature protections. P4 = discharge tube (compressor outlet) overheat. P5 = evaporator coil protection in cooling. P6 = condenser coil protection in cooling. P7 = evaporator coil protection in heating. Each trips the compressor to prevent damage from abnormal coil/line temperatures.
Most likely causes
- Restricted airflow over the evaporator (dirty filter/coil) or condenser (blocked rooftop vents) most likely
- Operating outside the unit's rated ambient temperature range common
- Low refrigerant charge or a refrigerant-circuit fault less common
Safe checks you can do yourself
- Clean or replace the return-air filter and check the interior evaporator grille for blockage
- Check the rooftop shroud vents for leaves/debris and clean as needed
- Avoid running the unit far outside its rated ambient range and let it rest before restarting
How to reset / clear P4 / P5 / P6 / P7
- Turn the unit off, clear any airflow restriction
- Disconnect power for about 2 minutes, then restore and restart
When to call a technician
If these codes recur after the filter and both coils/airflow paths are clean and ambient is in range, contact an authorized Dometic service agent — a refrigerant or sensor fault is likely.
Applies to
Dometic FreshJet Series 4 (FJX) · Dometic FreshJet Series 7 (FJX) · FreshJet inverter rooftop units
FAQ
What does Dometic Air Conditioner code "P4 / P5 / P6 / P7" mean?
Refrigerant-circuit temperature protections. P4 = discharge tube (compressor outlet) overheat. P5 = evaporator coil protection in cooling. P6 = condenser coil protection in cooling. P7 = evaporator coil protection in heating. Each trips the compressor to prevent damage from abnormal coil/line temperatures.
How do I reset Dometic Air Conditioner P4 / P5 / P6 / P7?
Turn the unit off, clear any airflow restriction Disconnect power for about 2 minutes, then restore and restart
What is the most common cause of P4 / P5 / P6 / P7 on a Dometic Air Conditioner?
The most likely cause is restricted airflow over the evaporator (dirty filter/coil) or condenser (blocked rooftop vents).
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Sources
- Dometic FreshJet Series 4 / Series 7 Operating Manual — 9620001685, Troubleshooting section, display codes P4, P5, P6, P7 (Dometic)
Note: FreshJet FJX inverter models only. Grouped as coil/discharge temperature protections; they are four separate codes. P8 is not listed in the manual table.
● Last verified 2026-06-29 · compiled from manufacturer documentation. Codes can vary by model year — always cross-check your unit’s manual.