Friedrich VRP Series Service & Parts Manual page 68

Diagnostic Codes
Diag Description
33 Compressor Lubrication
34 Unit Not Provisioned
35 Motor Board DC Bus Over Voltage
36 Motor Board DC Bus Under Voltage
37 Motor Board PCB Over Temperature
39 PSC Fan Low RPM
40 Wall Controller not Connected
41 EEV Fault
42 Compressor Speed Sync Error
43 Motor Board Communication Issue
68
TROUBLESHOOTING
Diagnostic Check point
1. The Compressor has run at low
frequency ( less than 35 Hz) for 200 con‑
secutive minutes and requires lubrication
2. Monitors if the FMC has not provisioned
Provisioned is defined as both switch and
"provision" data has been set
The bus voltage on the motor board is too
high. (> 420VDC)
The bus voltage on the motor board is too
low. (< 200VDC)
The temperature on the PCB is too high
to continue operation. (IPM temperatures
> 96°C)
The Indoor Fan's RPM is less than 60% of
its commanded RPM for 5 minutes
The FMC determines the Wall Controller is
not connected
The EEV returns a fault status in the FMC
The compressor speed feedback does not
match what the drive expects the speed
should be.
FMC not receiving feedback information
from the motor boad.
Solution
Replace with provisioned the FMC
"This error should automatically correct
itself. If error persists:
1. Verify input voltage to step down
transformer (265V models only)
2. Verify input voltage to the motor board.
3. Attempt to reboot the unit.
4. Replace the motor board."
"This error should automatically correct
itself. If error persists:
1. Verify input voltage to the motor board.
2. Attempt to reboot the unit.
3. Replace the motor board."
"This error should automatically correct
itself. If error persists:
1. Verify that no air recirculation is
happening in the outdoor section of the
unit.
2. Attempt to reboot the unit.
3. Replace the motor board.
4. Replace compressor."
Check all wiring between the FMC and
Wall Controller
"This error should automatically correct
itself. If error persists:
1. Check compressor wires for damage.
2. Verify connection of the compressor
wires.
3. Verify indoor/outdoor fan operation.
4. Verify system pressures.
5. Replace the motor board."
"1. Verify wiring from FMC to RS‑485
board.
2. Verify wiring from RS‑485 board to
motor board.
3. Check for visible damage on RS‑485
board. Replace if damaged.
4. Check for visible damage on motor
board. Replace if damaged.
5. Check for visible damage on the FMC.
Replace if damaged.
6. Check the motor board for the following
LED sequence RED: off, YELLOW: blinking,
GREEN: blinking. If LED sequence is
active, replace the motor board, else
replace the FMC."