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

⚠️ Safety Notice – Reverse Cycle Air Conditioners

This equipment must only be installed, commissioned, serviced and repaired by suitably qualified and licensed personnel.


Before commencing work, complete a task-specific risk assessment and ensure electrical isolation procedures, safe access, adequate service clearances and appropriate PPE have been considered. All work must comply with applicable regulations, standards and manufacturer requirements.


Particular care must be taken when working around electrical systems, refrigerant circuits, moving parts, roof spaces, ceiling spaces, confined spaces and working-at-heights hazards where applicable.


Do not proceed if safe access, required clearances, confined space risks or appropriate safety controls cannot be achieved and maintained. 


Safety takes priority over diagnosis, repairs, installation schedules and customer expectations. If the task cannot be completed safely, it must not proceed until the risks have been adequately controlled.


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.