Fault Code E6: Indoor / Outdoor Communication Fault - Braemar KDHA R32 Ducted Inverter (KDHA070–160 / KCHA070–160)

Applies To

Braemar KDHA R32 ducted inverter systems only, as covered in KDHA‑03‑A Service Manual.

Indoor Units

  • KDHA070D1S
  • KDHA100D1S
  • KDHA125D1S
  • KDHA140D1S
  • KDHA160D1S

Outdoor Units

  • KCHA070D1B
  • KCHA100D1B
  • KCHA125D1B
  • KCHA140D1B
  • KCHA160D1B

Service Manual Reference (KDHA‑03‑A)

  • Error Code Listing: Error Codes section, pages 28–30 (E6 – Communication Fault)
  • Diagnostic Guidance: Troubleshooting – Flowcharts, from page 31 onward (communication and control faults)
  • Wiring Schematics (Indoor ↔ Outdoor): pages 16–19

What Does E6 Mean?

E6 indicates a communication fault between the indoor unit and the outdoor unit.

If valid communication signals are not detected between the indoor and outdoor control boards within a specified time, the system will stop operation as a protective measure.

Common Symptoms

  • System does not start heating or cooling
  • Indoor fan may run, but compressor does not operate
  • E6 fault code displayed on the wired controller or indoor unit display
  • Power reset may temporarily clear the fault, but E6 returns

Likely Causes

Based on the KDHA service manual error code logic and troubleshooting flowcharts, common causes include:

  • Communication wiring issue
    • Communication cable disconnected or not terminated correctly
    • Damaged cable (cut, crushed, or pinched)
    • Poor or corroded terminal connections
  • Incorrect wiring
    • Wiring connected to incorrect terminals
    • Incorrect polarity between indoor and outdoor units
  • Power supply issue
    • Power not present at either indoor or outdoor unit
    • Voltage instability affecting control boards
  • Control board fault
    • Indoor PCB fault
    • Outdoor main PCB fault

Notes for Service

  • Verify the indoor ↔ outdoor communication cable is connected to the correct terminals at both units and is secure.

  • Inspect wiring for damage, corrosion, or loose connections.

  • Confirm correct polarity and wiring size as per the KDHA wiring diagrams.

  • Ensure stable and correct power supply to both indoor and outdoor units.


  • All service work must be carried out by licensed technicians trained in handling flammable refrigerant R32, in accordance with KDHA service manual safety requirements.