Fuses F1 or F2 blown — Solenoid valve or wiring fault

What does F1 or F2 (blown) mean?

One or both of the F1 and F2 fuses on the outdoor multi controller circuit board have blown. This indicates a potential electrical problem with components like the solenoid valves (SV1, SV2, 21S4) or the bypass valve (SS), or their associated wiring.

• Short circuit in a solenoid valve (SV1, SV2, 21S4) or bypass valve (SS)
• Damaged or loose wiring connections to the valves
• Internal fault on the multi controller circuit board

Click steps to track your progress.

1. 1

   Turn off the main power supply to the Mitsubishi Electric MXZ outdoor unit at the electrical breaker.

2. 2

   Visually inspect the wiring around the solenoid valves (SV1, SV2, 21S4) and the bypass valve (SS) for any signs of damage or loose connections.

3. 3

   If no obvious external issues are found, contact a qualified service technician to diagnose and repair the fuse, valves, or wiring.