Friedrich VRP12K, Service And Parts Manual

Page: 174 / 221

174 PB
TROUBLESHOOTING
Diag
#
Description Diagnostic Check point Solution
32
MCS Compressor Current Fault.
The MCS board has flagged a current fault
on the Compressor axis and notified the FMC
1.Short on the MCS board
2. Improperly wired compressor
3. Grounded/Demagged compressor
1.Short on the MCS board
2. Improperly wired compressor
3. Grounded/Demagged compressor
33 Compressor Lubrication
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
34 Unit Not Provisioned
Provisioned is defined as both switch and
“provision” data has been set
Replace with provisioned the FMC
35
MCS DC Bus Over Voltage
The MCS board has flagged an Over Voltage
fault on the MCS DC Bus and notified the FMC
The MCS bus voltage rose above ~465 VDC
when one of
the motor axis was enabled.
Power cycle the unit and see if the problem
persists, if so:
1. Replace the MCS board
36
MCS DC Bus Under Voltage
The MCS board has flagged an Under Voltage
fault on the MCS DC Bus and notified the FMC
The MCS board has flagged an Under Voltage
fault on the MCS DC Bus and notified the FMC
Power cycle the unit and see if the problem
persists, if so:
1. Check line voltage
2. Replace the MCS board.
37 MCS Board Over Temperature
1. The MCS board is reporting a board
temperature of greater than 60°C
2. The MCS board components are not being
properly cooled while running
under heavy load. (greater than 70°C/160°F)
1. Verify proper installation
2. Replace MCS board
38 MCS Heatsink Over Temperature
1. The MCS board is reporting a heat sink
temperature of greater than 60°C
2. The MCS heat sink components are not
being properly cooled while running
under heavy load. (greater than 70°C/160°F)
1. Verify proper installation
2. Replace MCS board
39 PSC Fan Low RPM
The Indoor Fan’s RPM is less than 60% of its
commanded RPM for 5 minutes
40 Wall Controller not Connected
The FMC determines the Wall Controller is
not connected
Check all wiring between the FMC and Wall
Controller
41 EEV Fault The EEV returns a fault status in the FMC
43 MCS Communication Failure If no “good” message between the FMC and
MCS has occurred in 15 min‑ utes the error
is reported.
Replace the communication wire between
the MCS
and FMC.
44 Reversing Valve out of Position (Stuck) The RV is in the incorrect position (On/Off)
for the mode that the system is in
The Discharge Air temperature is not
indicative of active cooling or heating for 5
minutes
46 Indoor Coil > 175°F for 5 consecutive minutes The T5 sensor reads a temperature greater
than 175°F for 5 consecutive minutes