FE & H8 Error CodesUpdated 4 days ago

Introduction

The "FE" and "H8" error codes indicate a T3 or T5 sensor disconnect error. This article is for Vertex Ducted Central Split (DYC-18) systems. 

Cause: The probe is in the wrong position. 

Troubleshooting Diagram

Troubleshooting Notes

• Check whether the positions of the T3 and T5 probes have changed. For example, if the exhaust probe T5 falls out, the measured temperature is not the real exhaust temperature. 
• Check whether the T3 and T5 probes are installed in the correct position on the pipe. Eliminate the possibility of a wrong installation. 
• Use a multimeter to measure the sensor resistance to see if the sensor is damaged. 
• If all of the above is OK, replace the main control board of the external unit.