Bosch F3 error code

What it means

F3 means compressor discharge temperature sensor error. In plain English, the named temperature or air-quality sensor is not sending a believable reading, so the control cannot trust that part of the system.

Urgency

Likely causes

1. The named sensor has failed or drifted out of range
2. Sensor connector or harness is loose, damaged, or corroded
3. Control board input is misreading the sensor circuit

Homeowner fix

Turn the system off with the remote, then power cycle once at the breaker or disconnect if you can do that safely. Do not open covers, unplug sensors, or spray cleaner into the sensor area.

When to call a pro

Call a licensed HVAC technician if F3 returns after one safe reset or the condition will not clear. Tell them the official source lists F3 as Compressor discharge temperature sensor error.

Repair vs replace

This fault is usually repairable. Replacement is worth comparing only if an older system also needs major board, compressor, or refrigerant-circuit work.

• Bosch Climate 5000 A/B legacy R-410A 9,000 BTU Regular (BMS500-AAU009-1AHWXB / BMS500-AAS009-1CSXRA)

  Climate 5000 A/B legacy R-410A

• Bosch Climate 5000 A/B legacy R-410A 12,000 BTU Regular (BMS500-AAU012-1AHWXB / BMS500-AAS012-1CSXRA)

  Climate 5000 A/B legacy R-410A

• Bosch Climate 5000 Gen 4 R-454B 6,000 BTU Regular (BMS500-AAU006-1AHWXD / BMS500-AAS009-1CSXRD)

  Climate 5000 Gen 4

• Bosch Climate 5000 Gen 4 R-454B 9,000 BTU Max Performance (BMS500-AAU009-1AHWXD / BMS500-AAS009-1CSXHD)

  Climate 5000 Gen 4

For your technician

Technician note: verify sensor placement, connector condition, resistance/output against the service data, harness continuity, and PCB input. Source: Bosch Climate 5000 G2 A/B IDU service manual Table 14 and ODU service manual Table 12; supporting diagnosis sections where listed; Table 12/Table 14; temperature-sensor diagnosis. Page context: Bosch maps this display to the Climate 5000 A/B legacy R-410A line; source: Bosch Home Comfort official Climate 5000 G2/A-B Ductless AC-HP IDU and ODU Service Manuals, wall-mounted error-code tables and diagnosis sections; display convention: match the letter F and three marker exactly before comparing neighboring codes.

Which systems show it

Climate 5000 A/B legacy R-410A

Related troubleshooting

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

Related codes

Source

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