37
Fault
Solution
Fault
Solution
No Display on Master Module
• Check main disconnect for power
• Check circuit breakers in module
• Check transformer in modules
• Check for 24V at J1 on board
100% Demand,
chiller won’t load
• Turn chiller on
• Check sensors
• Check load limit setting in system variables
Excessive Cycling
• Check VSP setting is system variables
• Check entering CHW sensor location
• Look for system problem (low water Volume,
low load)
EX 1,2, Interlock
• Check appropriate interlock component
• Check jumpers on TB11 in master control
EX 4 Interlock
• Check for proper rotation, phasing
• Check PPM device
High Discharge Pressure (HP)
• Check strainers in condenser headers
• Check condenser water flow
Waiting For Chilled Water Flow
• Check CHW pump
• Check flow switch operation
• Check filter strainers
• Check TB11 inputs #3 - #7
Low Suction Pressure (LP)
• Check refrigerant charge / leaks
• Check expansion valve
Low Suction Temperature
• Check suction sensor
• Check set-points in system variables
• Check for flow restriction
Waiting For Condenser
Water Flow
• Check CW pump
• Check flow switch operation
• Check filter strainers
• Check TB11 inputs #3 - #8
Communication Error
• Check settings in system variables
• Check cables at J11 comm ports
• Check dip switch settings
Low Chilled Water Temp
• Check LCHW sensor
• Check set-points in system variables
• Check for flow restriction
Circuit Fault
• Check components in control circuit
• Check wire crimps in control circuit
• Check ratio of HP to LP
No Demand
• Check entering CHW sensor
• Check set-points in system variables
• Check sensor location
P Lan Error
• Check cables at J11 comm ports
• Check for possible power issues
100% Demand all the time
• Check entering CHW sensor
• Check set-points in system
variables
Troubleshooting
Multistack modular chillers use the Carel PCO3 master control. A user manual for the PCO3 controller is supplied with the submittal package. The user
manual details the different status screens and explanations of system or module faults. Use the following guide to troubleshoot modules and the PC03
controller.
