ACiQ mini split error code Hd
Refrigerant leakage protection. Also shown as HD.
- TypeProtection
- SystemRefrigerant circuit
- Can I fix it?Technician job
- Applies toK-series (ACiQ-K09W-HP…, TCL-built)
What Hd means on a ACiQ
The refrigerant leak sensor (on units fitted with one) detected refrigerant in the indoor unit and shut the system down. Treat this seriously: ventilate the room.
On this platform, Hd is a protection: the system stopped or throttled itself to prevent damage; many clear on their own once conditions return to normal.
Common causes
- A refrigerant leak inside the indoor unit or at its connections.
- A contaminated or failed leak sensor.
How to fix it yourself
Do the reset and the visual checks, but the underlying repair needs a technician with a meter and the service manual.
- Open windows and ventilate the room. Do not use open flames nearby.
- Turn the system off at the breaker.
- Do not reset and run it until the source is found.
Switch off power at the breaker before opening either unit. Capacitors in the outdoor unit hold a charge for several minutes after power is cut.
When to call a technician
Call a technician; this is a safety shutdown.
Which ACiQ units show Hd
This page applies to ACiQ Standard single-zone (ACiQ-09Z-HP…B / W-HP) and multi-zone and K-series (ACiQ-K09W-HP…, SZDM / WHP / KZHP) units on the K-series (ACiQ-K09W-HP…, TCL-built). ACiQ's own documentation lists Hd as "Refrigerant leakage protection", the same definition used across the TCL platform it is built on. If your unit shows a code with a different shape (for example a four-character code, or a plain number), it is from a different table; use the lookup with your exact code.
Where ACiQ shows this code
K-series (ACiQ-K09W-HP…, TCL-built): The indoor display shows the code in place of the set temperature. E codes are faults: something has failed and needs diagnosis. P, H, d and F codes are protections: the system stopped or throttled itself to prevent damage, and many clear on their own once conditions return to normal.
Other ACiQ codes
Same part of the system as Hd:
Hd on other brands
The same characters do not always mean the same thing. Check the brand on your unit.
- Zone Air Hd Refrigerant leakage protection
Questions people ask
Can I reset a ACiQ Hd code myself?
Yes. Turn the system off at the breaker for five minutes, then restart it. If Hd comes back, the fault is real and needs the checks above.
Is it safe to keep running a ACiQ showing Hd?
Not repeatedly. A protection code means the unit stopped itself to prevent damage, and resetting it over and over can turn a cheap repair into a compressor failure. Reset once, check the basics, and stop if it returns.
What will a technician check for Hd?
Call a technician; this is a safety shutdown. Ask for the measurements, not just a parts quote.
Sources
- ACiQ Standard Single-Zone Mini Split Service Manual (SZ-Z-HP / W-HP), Quick Maintenance by Error Code
- ACiQ Mini-Split Air Handler and Condenser Service Manual (MS-SZDM / WHP / KZHP), error code table
Updated September 2026. Codes and definitions vary by model year. If your manual disagrees with this page, your manual wins. Send a correction.