Friedrich 18 error code

What it means

The DC inverter compressor did not start normally.

Urgency

Likely causes

1. Outdoor drive board failed
2. Compressor failed

Homeowner fix

Turn the system off and power cycle once if safe. Do not open the outdoor unit or attempt compressor work.

When to call a pro

Call a Friedrich-qualified technician if code 18 returns. Tell them the service manual lists DC compressor start failure.

Repair vs replace

Drive-board or compressor repairs can be expensive; compare major repair with replacement on older out-of-warranty systems.

• Friedrich Floating Air Pro 9,000 BTU R-454B 115V (FAHSW09A1C / FPHSR09A1C)

  Floating Air Pro

• Friedrich Floating Air Pro 9,000 BTU R-454B 208/230V (FAHFW09A3D / FPHSR09A3D)

  Floating Air Pro

• Friedrich Floating Air Pro 12,000 BTU R-454B 115V (FAHSW12A1C / FPHSR12A1C)

  Floating Air Pro

• Friedrich Floating Air Pro 12,000 BTU R-454B 208/230V (FAHFW12A3D / FPHSR12A3D)

  Floating Air Pro

For your technician

Official Friedrich indoor diagnostic table, PDF p.74: code 18 - DC compressor start failure; causes are failed outdoor drive board or failed compressor. Page context: Friedrich maps this display to the Floating Air Pro line; source: Friedrich Ductless Floating Air Pro Single Zone Service Manual, R-454B Refrigerant, 96112000_00; display convention: match the eighteen marker exactly before comparing neighboring codes.

Which systems show it

Floating Air Pro

Related troubleshooting

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

Related codes

Source

Next step