24VNA6 / 25VNA4 seriesCarrier 88 fault code (24VNA6 / 25VNA4)

Unexpected VFD Reset; VFD Reprogramming Failure; VFD Internal Error - Current Sensor; VFD Internal Error - IPM Temp Sensor; VFD Internal Error - DC Link Sensor; VFD Internal Error - PFCM Sensor A; VFD Internal Error - PFCM Sensor B; VFD Internal Error - Line Volt Sensor; VFD Internal Error - PFCM Temp Sensor; VFD Internal Error - DC Discharge

1. Code 88-15 VFD Internal Fault - Unexpect Reset / Code 88-55 VFD Lockout - Unexpected Reset

   Communication between the VFD and PCM is monitored continuously. If communication fails, the PCM will initiate a VFD reset in an attempt to restart the communicating components of VFD. The system will shut down and restart after 5 minute compressor protection timer expires. Three occurrences of code 88-15 within a 1 hour period will result in 88-55 malfunction and 2 hour lockout. Inspect PCM to VFD communication harness for damage and connectivity, replace if necessary. If this does not fix problem, the VFD communicating components have been damaged and VFD requires replacement.

   24VNA6-25VNA4-1SM, p. 23

2. Code 88-27 VFD Reprogramming Failure

   Code 88-27 indicates that an attempt to reprogram the VFD failed. If this diagnostic is not recent, then a subsequent reprogramming attempt may have succeeded. The technician should check the current VFD software version against the latest software release. If the VFD software is not the most current, then the VFD should be reprogrammed manually using the Infinity Control or the Carrier Service Tech App.

   24VNA6-25VNA4-1SM, p. 23

3. Code 88-31 VFD Internal Fault - Current Sensor / Code 88-71 VFD Lockout - Comp Current Sensor

   The VFD measures the compressor current value internally. If the compressor current measurement is not reported to VFD, it will shut down and attempt a restart after 5 minute compressor protection timer expires. Operating VFD without monitoring compressor current may result in compressor damage. Three occurrences of code 88-31 within a 4 hour period will result in 88-71 malfunction and 4 hour lockout. While this fault or malfunction is active the unit is inoperable. This malfunction, once set, is unlikely to go away and indicates VFD damage. Manually power cycle outdoor unit with disconnect, if malfunction persists replace VFD.

   24VNA6-25VNA4-1SM, p. 23

4. Code 88-32 VFD Internal Fault - IPM 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 IPM temperature sensor fails it will no longer be capable of preventing the IPM module 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.

   24VNA6-25VNA4-1SM, p. 23

5. Code 88-33 VFD Internal Fault - DC Link Sensor / Code 88-73 VFD Lockout - DC Link Sensor

   The VFD measures the DC voltage value internally. If the DC voltage measurement is not within acceptable operating parameters the VFD will shut down and attempt a restart after 5 minute compressor protection timer expires. Three occurrences of code 88-33 within a 4 hour period will result in 88-73 malfunction and 4 hour lockout. While this fault or malfunction is active the unit is inoperable. This malfunction, once set, is unlikely to go away and indicates VFD damage. Manually power cycle outdoor unit with disconnect, if malfunction persists replace VFD.

   24VNA6-25VNA4-1SM, p. 23

6. Code 88-34 VFD Internal Fault - PFCM Sensor A / Code 88-74 VFD Lockout - PFCM Sensor A

   The VFD has internal current measurement to protect PFC components from exceeding current thresholds that may shorten the VFDs operating life. If the PFCM Sensor A exceeds safe reliable value, the VFD will shut down immediately and attempt a restart after 5 minute compressor protection timer expires. Three occurrences of code 88-34 within a 4 hour period will result in 88-74 malfunction and 4 hour lockout. While this fault or malfunction is active the unit is inoperable. This malfunction, once set, is unlikely to go away and indicates VFD damage. Manually power cycle outdoor unit with disconnect, if malfunction persists replace VFD.

   24VNA6-25VNA4-1SM, p. 23

7. Code 88-35 VFD Internal Fault - PFCM Sensor B / Code 88-75 VFD Lockout - PFCM Sensor B

   The VFD has internal current measurement to protect PFC components from exceeding current thresholds that may shorten the VFDs operating life. If the PFCM Sensor B exceeds safe reliable value, the VFD will shut down immediately and attempt a restart after 5 minute compressor protection timer expires. Three occurrences of code 88-35 within a 4 hour period will result in 88-75 malfunction and 4 hour lockout. While this fault or malfunction is active the unit is inoperable. This malfunction, once set, is unlikely to go away and indicates VFD damage. Manually power cycle outdoor unit with disconnect, if malfunction persists replace VFD.

   24VNA6-25VNA4-1SM, p. 23

8. Code 88-36 VFD Internal Fault - Line Volt Sens / Code 88-76 VFD Lockout - Line Volt Sensor

   The VFD has internal voltage measurement to protect components from operating outside of voltage thresholds that may shorten the VFDs operating life. If the line volt sensor value is outside of safe reliable range, the VFD will shut down immediately and attempt a restart after 5 minute compressor protection timer expires. Three occurrences of code 88-36 within a 4 hour period will result in 88-76 malfunction and 4 hour lockout. While this fault or malfunction is active the unit is inoperable. This malfunction, once set, is unlikely to go away and indicates VFD damage. Manually power cycle outdoor unit with disconnect, if malfunction persists replace VFD.

   24VNA6-25VNA4-1SM, p. 23

9. 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.

   24VNA6-25VNA4-1SM, p. 24

10. 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.

    24VNA6-25VNA4-1SM, p. 24