This is for troubleshooting the E-320 , We found in 2017 some of the control boards had hair line cracks on some solder connections , these should have all been corrected now in the field . There is a HUB DOC-153717 That shows where the cracks were located , they could only be seen with and magnifying glass .
E320 on Mini VRF and C– Series (OLP) sensor open or short.
2 Causes:
1. Shorted or open Compressor top sensor (see below for testing sensor)
2. Defective circuit board
It has been confirmed by Engineering that some units have wiring that needs to be routed differently in the cabinet. If
wiring does not have enough slack and is too tight, it can cause a defect to the solder joint if the harness vibrates and
pulls on the plug connection.