Scotsman CU1526 - Troubleshooting Freeze Time and Compressor Issues; Further Troubleshooting for Freeze Time Shutdowns; Diagnosing Compressor Not Operating

Service Diagnosis
Problem Likely Cause Probable Solution
Shut down on maximum
freeze time
Pump hose disconnected Check hose
Compressor not operating
Check compressor contactor,
check controller using test mode
Check compressor start
components, check PTCR
resistance and temperature
Check compressor voltage
Check compressor windings
Low refrigerant charge
Add some refrigerant and restart
unit. If cycle time improves, look for
leak.
Hot gas valve leaks through during
freeze
Check hot gas valve for hot outlet
during freeze
Thermostatic expansion valve bulb
loose
Check bulb
Thermostatic expansion valve
producing very low or very high
superheat
Check evaporator superheat,
change TXV if incorrect
Compressor inefficient
Check compressor amp draw, if
low and all else is correct, change
compressor
May 2008
Page 29
CU1526, CU2026, CU3030
Service Manual