Trane 4TXM2318BF300AA Service Manual page 138

[17] 4-Way Valve Reversing Failure
If connection between 4-way
valve and PCB is good
If coil of 4-way valve
fixed well and if its
characteristic is
If system meets
condition of 4-way
valve reversing: Pd-
Ps>0.6Mpa
Measure if CN5 voltage
on PCB is 208/230VAC
after 4-way valve reversing
conditon is met
If there is air noise after 4-way
valve reverses, and if the
temp. of connection pipes
with 4-way valve is
Y
correct
Y
Y
Y
normal
N
Reconnect
N
Fix again or replace the sensor
Y
Check if compressor is operation
N
Replace PCB
N
Replace 4-way valve
136