294
JOHNSON CONTROLS
FORM 201.21-NM4 (616)
294
JOHNSON CONTROLS
MAINTENANCE
EVACUATING A SYSTEM
If a system or a portion of a system needs to be evacuat-
ed, it should be evacuated to a minimum of 500 microns.
The system should then be able to hold the vacuum for
10 minutes with a maximum rise of 50 microns. If the
system is not able to hold a vacuum, recheck the system
for leaks.
TROUBLESHOOTING GUIDE (CON'T)
PROBLEM
POSSIBLE CAUSE
ACTION
System Fault:
MOTOR
CURRENT
LIMITING
High motor current
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.
Condensor coils dirty,
Clean condensor.
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.
IGBT 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.
(Always remove power to the chiller and assure the DC bus voltage has bled off)