SECTION 9 - MAINTENANCE
QUANTECH
155
FORM QTC4-NM1
ISSUE DATE: 4/2/2018
9
TABLE 25 - TROUBLESHOOTING GUIDE (CONT'D)
PROBLEM POSSIBLE CAUSE ACTION
SYSTEM STATUS:
MOTOR CURRENT
LIMITING
A high motor current anticipatory control
has activated current limiting.
Ambient temperature is high, normal
response from controller
Remote or panel limiting is in effect,
Normal response.
Excess charge in system, adjust charge.
Condenser coils dirty, Clean condenser.
Fans NOT operating. Check fans.
VSD FAULT:
HIGH BASEPLATE
TEMPERATURE
Coolant level low. Add coolant.
Glycol Pump is defective. Replace Glycol Pump.
VSD Board is defective Replace VSD Logic Board.
IBGT Module is defective. Check defective IGBT Module.
VSD FAULT:
LOW DC BUS VOLTAGE
SCR / Diode Module is defective. Check SCR / Diode Module.
SCR Trigger Board is defective. Check SCR Trigger Board.
NOTE: Always remove power to the chiller and assure the DC Bus voltage has bled off.