Bosch Mini Split F1 Error Code

What F1 means

F1 means an outdoor ambient temperature sensor error on Bosch Climate 5000 Gen 2 / legacy single-zone systems (indoor lamp group: 1 lit) - the outdoor ambient (T4) thermistor is 'open circuit or short circuited' or reading outside its window. Heat Pump Answers' Gen 2 table matches (F1 = outdoor ambient sensor, EC 53 / Gen 3 EH 6x equivalent). On a multi-zone outdoor board, F1 instead names indoor head A as the room with a failed sensor.

First checks before service

This page currently documents the safe reset triage. If the code returns, use the linked source manual or a qualified technician for code-specific diagnosis.

1. 1. One-time fault event (power disturbance or transient sensor reading) common DIY

   Check: Power-cycle at the breaker/disconnect (or unplug for CPAP), restore, and run the system while watching for the code.

   Fix: If the code does not return after a full run cycle, the fault was transient — monitor, no repair needed.

2. 2. Fault persists after a clean reset occasional pro only

   Check: If the code returns immediately or every session, note the conditions (startup, heating, after rain).

   Fix: A persisting code points at the component the manual assigns to this code — that repair is technician territory.