Mitsubishi

EA

Lockout

4-way valve

Did not shift or sensor disagrees.

3 plates — walk the one on the cabinet

First check

1 Confirm O/B is energized the way THIS outdoor expects

Most US splits energize O in cool. Some Rheem/Ruud energize B in heat. Read the Mitsubishi MSZ-FS diagram, not a generic heat-pump card. Solenoid voltage during the call, pressure swap, suction temp.

Expect: Correct 24 V at the solenoid for the mode that is failing.

The rest of the walkthrough is Diagnose.

On the plates

Solenoid voltage during the call, pressure swap, suction temp.
Solenoid voltage, pressure swap, suction temp.
Solenoid voltage during a heat/cool changeover.
Pressure swap at the outdoor. A branch box does not replace the 4-way.

Plates that use EA

MSZ-FS
M-series Hyper-Heating wall indoor · i-see sensor
Diagnose MSZ-FS — Sign in
MSZ-GL
M-series wall indoor · no i-see
Diagnose MSZ-GL — Sign in
MXZ-SM
MXZ multi-zone outdoor · branch box on some
Did not shift or pipe temp disagrees.
Diagnose MXZ-SM — Sign in

Same number, other makers

EA on Mitsubishi is not the same code on these plates.