Fault Code H5: IPM / Inverter Protection - Braemar KDHA R32 Ducted Inverter (KDHA070–160 / KCHA070–160)

Applies To

Braemar KDHA R32 ducted inverter systems only, as covered in the 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 (H5 – IPM / Inverter Protection)
  • Diagnostic Guidance: Troubleshooting – Flowcharts, from page 31 onward (inverter drive and electrical protection faults)
  • Electrical Data & Wiring: pages 15–19
  • Outdoor PCB Layouts: pages 20–24

What Does H5 Mean?

H5 indicates that IPM (Inverter Power Module) protection has activated in the outdoor unit.

The inverter drive has detected an abnormal electrical or thermal condition and has shut down compressor operation to protect the inverter module, compressor, and associated power components from damage.

Common Symptoms

  • System stops suddenly during operation
  • Compressor does not run
  • Outdoor unit shuts down and does not restart
  • H5 fault code displayed on the wired controller or indoor unit display
  • Fault may persist after isolating and restoring power

Likely Causes

Based on KDHA‑03‑A service manual logic and inverter protection behaviour, H5 will occur when the inverter detects unsafe operating conditions that could damage the IPM or compressor.

Common causes include:

IPM (Inverter Power Module) Over‑Temperature

  • Outdoor unit operating in high ambient conditions with insufficient heat dissipation
  • Restricted airflow through the outdoor unit due to:
    • Blocked air inlets or discharge paths
    • Outdoor unit installed too close to walls, fences, or other obstructions
    • Dirt, debris, or contamination inside the outdoor unit affecting airflow across the inverter heat sink
  • Ventilation openings obstructed or compromised after installation

Why this triggers H5:
The IPM contains internal temperature protection. If the module temperature exceeds safe limits, the inverter shuts down to prevent permanent semiconductor damage.

Electrical Supply Abnormalities

  • Supply voltage outside the allowable operating range
  • Voltage instability, fluctuations, or transient disturbances
  • Poor power quality from marginal electrical infrastructure or generator supply
  • Incorrect electrical connections affecting inverter input stability

Why this triggers H5:
The inverter continuously monitors supply conditions. Abnormal voltage or unstable input can cause excessive current draw and thermal stress, triggering inverter protection.

Abnormal Compressor Electrical Load

  • Compressor drawing higher than expected operating current
  • Mechanical resistance within the compressor
  • Internal compressor electrical fault detected by the inverter

Why this triggers H5:
The inverter monitors compressor current and load characteristics. Abnormal signatures are interpreted as a potential compressor or inverter risk, resulting in protective shutdown.

Inverter Drive / Outdoor PCB Fault

  • Internal failure of the IPM module
  • Inverter control circuitry malfunction
  • Degraded inverter components due to previous thermal or electrical stress

Why this triggers H5:
When inverter self‑monitoring detects conditions outside control tolerances, the outdoor PCB enforces shutdown to prevent further damage.

⚠️ IPM and inverter drive components are not field‑repairable.

Wiring or Connection Issues

  • Loose, poorly terminated, or incorrect power wiring
  • Overheated or discoloured terminals indicating high resistance
  • Incorrect wiring introduced during previous service work
  • Vibration‑related degradation of electrical connections over time

Why this triggers H5:
High resistance or intermittent electrical connections can create current spikes or heat buildup that activate inverter protection logic.

✅ Diagnostic intent:
H5 is designed to protect critical and high‑value inverter components. Repeated resets without resolving the underlying cause may result in permanent inverter or compressor damage.

Notes for Service

  • Allow the system to cool before attempting a restart, only after confirming safe operating conditions.

  • Inspect outdoor airflow and ventilation before proceeding with electrical checks.

  • Verify stable and correct power supply to the outdoor unit in accordance with KDHA electrical specifications.

  • Inspect all wiring connections for looseness, overheating, or visible damage.


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