H6 & P4 Error CodesUpdated 4 days ago

Introduction

The "H6" and "P4" error codes indicate an exhaust temperature too high protection. This article is for Vertex Ducted Central Split (DYC-18) systems. 

Cause: The exhaust temperature sensor reads a temperature that is too high (More than 239°F / 115°C). 

Troubleshooting Diagram

Troubleshooting Notes

• Connect a pressure gauge to measure whether the return gas pressure is too low (normally 0.7-0.9 Mpa). If the pressure is too low, add refrigerant. 
• Measure the resistance of the temperature sensor and check whether it drifts by comparing it with the resistance table. If it drifts, replace the sensor. 
• If the temperature sensor resistance is normal, check the exhaust in item 8 and compare it with the actual exhaust temperature. Use an infrared thermometer to measure the exhaust temperature. If the temperature of the main control board is unreasonable, replace the main control board. 
• If the above steps are normal, check whether the refrigerant system is normal, such as return air blockage, poor evaporation, compressor wear, etc.