Current Transformer (CT) System Abnormality

What it means

This code appears on Daikin split, ducted and cassette air conditioners and means the outdoor board is reading an implausible current from the current transformer (CT) or current detection circuit, such as almost no current while the compressor should be running. Without this reading the board cannot protect the compressor, so the unit stops. The same code can mean something else on other brands.

Models covered: Daikin split air conditioners and Daikin ducted/cassette (SkyAir) units, which share the same error code system; the code shows on the wired remote or via the wireless remote check function.

Related codes: H0L5E1U2

Symptoms3

• The unit stops shortly after starting and H8 appears.
• No cooling or intermittent cooling before it stops.
• The code may return after every restart.

Possible causes4

• A loose or burnt connection in the compressor or current sensing circuit.
• A faulty current transformer or current detection circuit on the outdoor PCB.
• Low or unstable supply voltage.
• A compressor fault that stops it drawing the expected current.

How to diagnose5

1. Switch the unit off at the breaker for several minutes, then restart.
2. Check that the supply voltage is stable.
3. A technician checks the compressor and supply connections on the outdoor board after discharging it.
4. The technician measures the running current with a meter and compares it with the board's reading or Daikin specifications.
5. If the actual current is normal and the code persists, the board is the likely fault.

How to fix5

1. Repair loose or burnt connections.
2. Fix the voltage problem or fit a voltage protector.
3. Replace the outdoor PCB if its current detection circuit is proven faulty.
4. If the compressor is not running properly, test it per the service manual.
5. Run and test the unit and confirm the code does not return.

Repair cost

In Saudi riyals; the highlighted part is the expected range for this fault.

Connection repairs are cheap; on most models the CT is part of the outdoor board, so replacing the board drives the higher cost.

Prices are rough estimates including the part and the technician’s fee, and vary with brand, model and part source.
Prices last updated: September 2026

Frequently asked questions