ACiQ FHCC error code

What it means

FHCC means the refrigerant leak sensor is not working correctly. Because that sensor is part of the R-454B A2L leak-detection system, treat FHCC as stop-use until a pro verifies the safety system.

Urgency

Likely causes

1. Dirty filters, blocked coil airflow, or an outdoor clearance problem increasing pressure or temperature
2. Low charge, overcharge, leak, or refrigerant-flow restriction
3. Discharge, pressure, or refrigerant sensor reading outside range
4. Compressor, valve, or outdoor board issue after airflow and charge are verified

Homeowner fix

Turn the system off, ventilate the space, avoid flames, sparks, and smoking, and do not reset the unit back into normal operation. Expected result: the system stays off until a licensed technician verifies the leak sensor and refrigerant circuit.

When to call a pro

Call a licensed HVAC technician before normal operation. Tell them the display is FHCC and the installation manual says the refrigerant sensor malfunctioned.

Repair vs replace

A leak-sensor replacement or minor leak repair may be reasonable, especially under warranty. If the repair involves a coil, buried line set, or repeated refrigerant loss, compare the quote with replacement.

• ACiQ Multi-Zone Extreme Series 2-Zone 18,000 BTU R-454B 208/230V (ACIQ-18Z-HH-M3C)

  Multi-Zone Extreme Series

• ACiQ Multi-Zone Extreme Series 3-Zone 27,000 BTU R-454B 208/230V (ACIQ-27Z-HH-M4C)

  Multi-Zone Extreme Series

• ACiQ Multi-Zone Extreme Series 4-Zone 36,000 BTU R-454B 208/230V (ACIQ-36Z-HH-M5C)

  Multi-Zone Extreme Series

• ACiQ Multi-Zone Extreme Series 5-Zone 48,000 BTU R-454B 208/230V (ACIQ-48Z-HH-M6C)

  Multi-Zone Extreme Series

For your technician

Technician note: Midea states the refrigerant sensor cannot be repaired and must only be replaced with the manufacturer-specified sensor; verify A2L safety operation after replacement. Page context: ACiQ maps this display to the Multi-Zone Extreme Series line; source: ACiQ Multi-Zone Service Manual and shared Midea D5CMRA Table 20 display reference; display convention: match the letter F, letter H, letter C, and letter C marker exactly before comparing neighboring codes.

Which systems show it

• ACiQ Multi-Zone Extreme Series R-454B systems using the shared Midea/ACiQ multi-zone platform.
• ACiQ Multi-Zone Standard Series R-454B systems where the ACiQ service manual lists the same EC/EH/EL/PC diagnostics.
• ACiQ wall-mounted, cassette, duct, console, and AHU indoor units listed in service manual section 7.2.

Sold under more than one brand

Shared with Midea. ACiQ and Midea document this code from the same manufacturer source, so FHCC means the same thing on either badge and the steps above apply.

Related troubleshooting

Use the symptom guide alongside the exact display code if the unit is flashing, cycling, or showing comfort symptoms.

Reset note

Turn the system off, ventilate the space, avoid flames, sparks, and smoking, and do not reset the unit back into normal operation. Expected result: the system stays off until a licensed technician verifies the leak sensor and refrigerant circuit.

Manual trigger

FHCC means the refrigerant leak sensor is not working correctly. Because that sensor is part of the R-454B A2L leak-detection system, treat FHCC as stop-use until a pro verifies the safety system.

Related codes

Source

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