High Compressor Discharge Pressure Shutdown

Common Symptoms

• Unit displays alarm code 00013 on the Display Module and shuts down the compressor
• Red alarm indicator lights up on the Display Module panel
• Refrigeration compartment temperature starts rising after the shutdown
• You may hear the unit attempt to restart and then trip off again on the same alarm
• High-side refrigerant gauges show abnormally elevated discharge pressure readings
• Condenser fan may still be running but the compressor has stopped
• Alarm log (accessed via the MENU key) shows 00013 logged with a timestamp

Probable Causes (Ranked by Likelihood)

• Dirty or plugged condenser coil blocking airflow and heat rejection Very Likely
• Condenser fan motor failed or fan blade broken, causing no airflow across the coil Very Likely
• Refrigerant overcharge putting excess refrigerant into the high side Likely
• Non-condensable gases (air, nitrogen) in the refrigerant circuit raising head pressure Likely
• High ambient temperature conditions pushing discharge pressure above the cutout setpoint Possible
• Defective or stuck high-pressure cutout switch sending a false shutdown signal Possible
• Liquid line or liquid line solenoid restriction forcing refrigerant to back up into the high side Less Likely

Step-by-Step Diagnostic Procedure

1. Check the alarm log first. Press MENU on the Display Module and scroll to the alarm history to confirm 00013 is active or recently logged. Note how many times it has tripped, as repeated trips in a short window point toward a persistent mechanical issue rather than a one-time event.

2. Inspect the condenser coil visually from the outside. Look for dirt, debris, insect nests, or road grime packed into the fins. A coil that you cannot see light through when you shine a flashlight from the inside needs to be cleaned before you can diagnose anything else. Wash it out with water from the inside out if possible.

3. Verify condenser fan operation. With the unit running in MANUAL mode, confirm the condenser fan motor spins freely, the blade is not cracked or missing a section, and the motor is not overheating. A fan drawing too much current or not spinning to full speed will cause head pressure to spike.

4. Check refrigerant pressures with a manifold gauge set if you have one available. On R-404A systems, high-side discharge pressure above approximately 350-375 psig at normal ambient temperatures (around 90-95 degrees F) is abnormal and confirms high head pressure. Compare readings to the pressure-temperature chart for R-404A or whatever refrigerant the unit is charged with (check the nameplate).

5. Look for signs of refrigerant overcharge. If discharge pressure is high but suction pressure is also abnormally high, and the unit has recently had refrigerant added, an overcharge is likely. Overcharge diagnosis and correction requires a certified refrigerant technician with recovery equipment.

6. Test the high-pressure cutout switch if pressures look normal. With gauges connected, verify the switch opens at its rated cutout pressure (typically around 375-400 psig for R-404A systems on Vector units). If the switch trips at a pressure well below spec, the switch itself may be faulty and need replacement.

7. Check ambient conditions. If the unit is sitting in direct sun in extreme heat (above 100 degrees F ambient) with poor airflow around the condenser, high discharge pressure can be a real condition, not a component failure. Make sure the trailer is positioned to allow air to flow through the condenser area and not recirculate hot exhaust air.

8. If cleaning the condenser and confirming fan operation does not clear the alarm and the unit continues to trip, stop running it and call a refrigeration technician. Internal refrigerant system work (recovering refrigerant, checking for non-condensables, correcting charge) requires EPA 608 certification and specialty equipment.

Frequently Asked Questions