186CNV / 284ANV: Service Manual
Manufacturer reserves the right to change, at any time, specifications and designs without notice and without obligations.
24
Code 88-37 VFD Internal Fault - PFCM Temp Sens
The VFD has internal temperature sensors to monitor critical power
components and take action if operating temperatures cross thresholds
that may shorten the VFDs operating life. If the PFCM temperature
sensor fails it will no longer be capable of preventing the PFC circuit
from operation above the safe reliable temperature threshold. If this fault
is active the VFD will continue to operate normally, since the only way
to correct this fault is to replace VFD.
Code 88-38 VFD Internal Fault - DC Discharge
Code 88-78 VFD Lockout - Int DC Discharge
The unit VFD converts boosts 230VAC line voltage and then converts to
DC voltage before switching the DC voltage on and off rapidly to create
a 3 phase waveform and operate compressor at varying speeds. This
fault becomes active when the DC voltage is shorted to ground and the
VFD will open the power relay. While this fault or malfunction is active
the unit is inoperable. The VFD will attempt to reset itself automatically
but if problem persists, the fault will escalate to 88-78 malfunction and
lock out system for 4 hours. Manually power cycle outdoor unit with
disconnect, if malfunction persists replace VFD.
