Part Number 80-0111-9 6/11 7
TROUBLESHOOTING
QM45/Q130/Q170/Q210/Q270 . . . . . . . . . 99
Diagnosing an Ice Machine
that Will Not Run . . . . . . . . . . . . . . . . . 99
Diagnosing Ice Thickness Control
Circuitry . . . . . . . . . . . . . . . . . . . . . . . .100
Ice Production Check . . . . . . . . . . . . . 103
Installation and Visual Inspection
Checklist . . . . . . . . . . . . . . . . . . . . . . . 104
Water System Checklist . . . . . . . . . . .105
Ice Formation Pattern . . . . . . . . . . . . .106
Safety Limit Feature . . . . . . . . . . . . . . 108
Analyzing Discharge Pressure . . . . . . 115
Analyzing Suction Pressure . . . . . . . .117
Hot Gas Valve . . . . . . . . . . . . . . . . . . . 121
Comparing Evaporator Inlet/Outlet
Temperatures . . . . . . . . . . . . . . . . . . .125
Discharge Line Temperature Analysis 126
Refrigeration Component Diagnostic
Chart . . . . . . . . . . . . . . . . . . . . . . . . . . 128
Final Analysis . . . . . . . . . . . . . . . . . . .130
Refrigeration Component Diagnostic Chart
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .131
QM20/QM30 . . . . . . . . . . . . . . . . . . . . . . . .134
Diagnosing an Ice Machine
that Will Not Run . . . . . . . . . . . . . . . . . 134
Refrigeration Diagnostics . . . . . . . . . . 135
Ice Formation Pattern . . . . . . . . . . . . .137
QM45 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 139
Electrical . . . . . . . . . . . . . . . . . . . . . . . 139
Refrigeration Diagnostics . . . . . . . . . . 140
Flooding Expansion Valve . . . . . . . . . .143
Starving Expansion Valve/
Low Refrigerant Charge . . . . . . . . . . .143
Overcharged System . . . . . . . . . . . . . 143
SM50 . . . . . . . . . . . . . . . . . . . . . . . . . . . . .144
Diagnosing an Ice Machine
that Will Not Run . . . . . . . . . . . . . . . . . 144
Ice Machine Will Not Harvest . . . . . . . 145
Ice Quality Is Poor — Cubes are
Shallow, Incomplete or White . . . . . . .146
