H3 & PD Error CodesUpdated 4 days ago

Introduction

The "H3" and "PD" error codes indicate high pressure abnormal failure protection in Heating mode. This article is for Vertex Ducted Central Split (DYC-18) systems. 

Cause: The pressure valve checked by the pressure sensor exceeds the protection value. 

Abnormal high pressure (Heating mode) > 3.6Mpa

Troubleshooting Diagram

Troubleshooting Notes

• Check whether the pressure sensor wiring is firm and confirm the wiring is normal. 
• Check whether the indoor coil side has poor dissipation and ensure there is no problem with heat dissipation. Connect the pressure gauge, operate unit, measure the actual pressure value, and check the 16th parameter on the display board. Compare the measured value with the spot check value. 
• If the measured value is different from the spot check value and the difference is too large, replace the pressure sensor. 
• If the measured value is the same as the spot check value and does not exceed the protection range, replace the main control board. 
• If the measured value is the same as the spot check value and exceeds the protection range, it is a system problem and requires checks for system blockage, leakage, insufficient refrigerant, etc.