186CNV / 284ANV: Service Manual
Manufacturer reserves the right to change, at any time, specifications and designs without notice and without obligations.
21
To troubleshoot this fault, remove the PCM-VFD harness from the PCM
while leaving the other end connected to the VFD. Check the resistance
between the pins 6 & 7 of the harness connector. The resistance should
be approximately 720 ohms. If the resistance is much higher than 720
ohms, then remove the connector at the other end of the cable from the
VFD. Check the resistance between pin 6 of the PCM connector and pin
5 of the VFD connector, then pin 7 of the PCM connector and pin 6 of
the VFD connector. If either of these shows a resistance higher than just
a few ohms, then the cable is the cause of the problem. If the cable
checks OK, the problem may be with the VFD. Check the resistance
between pins 5 and 6 of the VFD connector. If this resistance is
significantly higher than 720 ohms, then the problem is within the VFD.
Code 66-42 VFD Control Relay Shorted Lockout
The PCM commands the VFD to close a relay in the power circuit
during VFD initialization. If PCM senses the VFD relay coil is shorted
to ground this code is set. While this code is active the VFD will not be
powered and system is inoperable. 12VDC is fed from Pins 6&7 of the
PCM connector into pins 5&6 of the VFD connector via communication
cable as long as system is ready to run (other faults that stop system from
operation are not active). Check to ensure comm harness is not damaged
and shorting to ground or another wire.
To troubleshoot this fault, remove the PCM-VFD harness from the PCM
while leaving the other end connected to the VFD. Check the resistance
between the pins 6 & 7 of the harness connector. The resistance should
be approximately 720 ohms. If the resistance is much lower than 720
ohms, then remove the connector at the other end of the cable from the
VFD. Check the resistance between pins 5 and 6 of the comm cable
connection at VFD. If this resistance is significantly lower than 720
ohms, then the problem is within the VFD.
VFD Related Faults General Info
Occasional VFD faults may occur that are caused by specific external
circumstances. In these cases the VFD will self-recover and continue to
operate normally. Once faults escalate to malfunctions permanent
damage may be present. The service person should use judgement when
replacing components to determine if occasional external conditions are
present or if equipment is damaged and require replacement because
system is not providing expected performance.
Code 81-13 VFD System Fault - PFC
Code 81-53 VFD System Lockout - PFC
The power factor correction circuit (PFC) in VFD introduces an
inductance which corrects the current phase shift inherent with powering
motors. This in turn minimizes the reactive power transmitted back to
input power cables. This fault is set when the PFC circuit exceeds a peak
current limit when driving compressor. System will shut down and VFD
will reset, if demand persists, system will attempt to resume normal
operation. After 2 occurrences within 10 minutes, code 81-53 is set and
system is locked out for 4 hours. A power cycle will clear malfunction
lockout timer. Continued malfunctions indicate high current situation.
This is likely due to VFD or compressor damage. Measure reactor(s)
resistance. As reactor charges the resistance will be reduced to 0. If
measurement is open, replace reactor. Otherwise replace VFD.
Code 81-14 VFD System Fault - Unbalanced PFCM
Code 81-54 VFD System Lockout - Unbalance PFCM
Applicable to 4 and 5 ton models only with multiple reactors. This fault
occurs when current in PFCM circuits is not balanced. It is most likely
caused by a disconnected or faulty reactor. The VFD will shut down and
attempt to restart after each occurrence of code 81-14. After 2
occurrences within 10 minutes, code 81-54 is set and system is locked
out for 4 hours.
Disconnect and measure resistance of both reactors in system. As reactor
charges the resistance will be reduced to 0. If measurement is open,
replace reactor. Otherwise replace VFD.
Code 81-58 VFD System Lockout - Wiring Error
This fault occurs when the VFD senses that 1 or more of the compressor
wires are not connected to VFD. While this fault is active the system is
inoperable. Check compressor wire harness at each end and ensure
connections are tight fitting and wires are undamaged. Perform
continuity test on compressor harness with DMM. Check resistance of
compressor windings at VFD end of compressor harness to ensure no
windings are open. Refer to Table 3 for compressor winding resistance
by outdoor model.
Code 82-11 VFD System Fault - Line Current Lim
The VFD monitors input current and will limit or reduce compressor
speed if the current rises above threshold. Current limits are model
specific. While code 82-11 is active the VFD will continue to operate
compressor at a reduced or limited speed, while fan operation will not be
affected directly. This code will clear once VFD input current drops
below threshold. Low input voltage combined with high load is the most
likely cause of this code. Check system for overcharge and
indoor/outdoor coil blockage as well as input voltage.
Code 82-13 VFD Reset with Power Dropout
Code 82-53 VFD Lockout - Reset with Power Drop
This code indicates the VFD has reset itself due to a line voltage loss.
When this code is set the PCM will complete a shutdown, reset the VFD,
and restart if demand is still present. The system should resume
operation after the 5 minute compressor protection time delay expires. 3
occurrences of code 82-13 within a 1 hour period will result in a code
82-53 and 2 hour lockout. Occasional occurrences of this code may
happen due to momentary power loss or electrical noise from utility.
Check tightness of all line voltage connections. Loose connections can
cause momentary voltage drop due to vibration and trigger this fault. If
all connections are tight, additional steps involving the local power
utility or addition of external power conditioner may be required.
Code 82-15 VFD Fault with Power Dropout
Code 82-55 VFD Lockout - Fault with Power Drop
This code indicates the VFD has shutdown due to a line voltage loss.
When this code is set the PCM reset the VFD, and restart if demand is
still present. The system should resume operation after 5 minute
compressor protection time delay expires. 4 occurrences of code 82-15
within a 1 hour period will result in a code 82-55 and 2 hour lockout.
Occasional occurrences of this code may happen due to momentary
power loss or electrical noise from utility. This code can be paired with
other codes if electrical noise is present. Check tightness of all line
voltage connections. Loose connections can cause momentary voltage
drop due to vibration and trigger this fault. If all connections are tight,
additional steps involving the local power utility or addition of external
power conditioner may be required.
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