Manitowoc QuietQube Indigo Series Technician's Handbook page 146

QuietQube® Model Final Analysis
The column with the highest number of Checkmarks
identifies the refrigeration problem.
COLUMN 1 - HARVEST VALVE LEAKING
Replace the valve as required.
COLUMN 2 - LOW CHARGE/TXV STARVING
Normally, a starving expansion valve only affects the
freeze cycle pressures, not the harvest cycle
pressures. A low refrigerant charge normally affects
both pressures. Verify the ice machine is not low on
charge before replacing an expansion valve.
1. Do not add charge to QuietQube models. The
symptoms of a QuietQube condensing unit low on
charge will result in a safety limit #1 in cool
ambient temperatures. Check the liquid line
temperature at the ice machine. The liquid line will
be hot with a normal or below normal head
pressure in freeze when the ice machine is low on
refrigerant.
2. Find the refrigerant leak. The ice machine must
operate with the nameplate charge. If the leak
cannot be found, proper refrigerant procedures
must still be followed Change the liquid line drier.
Then, evacuate and weigh in the proper charge.
3. Verify refrigerant charge by weight when
recovering to prevent misdiagnosis of the
expansion valve.
146 Part Number STH026 8/12