Page 8
– Bulletin 100-50-5.2
Table 4 - Troubleshooting
SYMPTOM
CHECK
Will not power up
Wiring terminals (power) at transformer and controller
Supply voltage (see Technical Specification section)
Subcooling below
setpoint
EPR valve setting (too low)
Pressure Transducer Range (correct transducer set up in controller; 0-300, etc.)
Pressure Transducer Type (correct transducer set up in controller; gauge/sealed versus absolute)
Temperature Sensor Type (correct sensor set up in controller; 2K or 3K (see Appendix J - Sensor
Installation, page 16)
Temperature Sensor wiring (ensure sensor locations are not mis-matched)
Proper foam insulation on piping and sensors
Return Gas High Limit (
rghL
) set too low
Subcooling above
setpoint
EPR valve setting (too high)
Liquid condition entering expansion valve
Pressure Transducer Range (correct transducer set up in controller; 0-300, etc.)
Temperature Sensor Type (correct sensor set up in controller; 2K or 3K, see Appendix J - Sensor
Installation, page 16)
Subcool Control expansion valve (correct valve set up in controller; 1596, 2500 steps, etc.)
Subcool Control expansion valve sizing (if valve position in controller is at 100% when symptom
exists, valve may be undersized)
Heat exchanger sizing
Proper system refrigerant charge
Oil return (oil logging in heat exchanger)
Liquid line filter (clogging or excessive pressure drop)
No Subcooling
Subcool Control power
Pump down signal (ensure Subcool Control expansion valve is not closed)
Proper system refrigerant charge
Liquid line filter (clogging or excessive pressure drop)
Proper Subcooler Off Temperature Differential (
SboF
) (see Section 4 - System Operation, page 4)
Subcool Control Expansion Valve operation
Subcooling Unstable
Wiring terminals (power) at transformer and controller
Wiring terminals (sensors) at controller
Sensor locations
Sensor operation (See additional information under Section 7 - Troubleshooting, page 7)
Proper heat exchanger flow direction
Stability of head pressure control valves (upstream of Subcool Control expansion valve)
Stability of suction pressure control valves (downstream of Subcool Control expansion valve)
Stability of rack controller (verify compressors are not short cycling)
Controller PID setting (See Section 6 - PID Tuning, page 6)
No Communication
Wiring at controller and master communication board
Addresses of controllers (see Section 5 - Controller Networking, page 5)
Communication errors
Wiring terminals at controller and master communication board
Network wiring from controller to master communication board (see Section 5 - Controller
Networking, page 5)
Proper network wire grounding (see Section 5 - Controller Networking, page 5)
Termination resistors (see Section 5 - Controller Networking, page 5)
Network parameters in controller and master communication board (baud rate, parity, etc; see
Section 5, page 5)
Third party controllers on Subcool Control network
Setpoints not saved
ESC must be set within 60 seconds of changes being made
