Manitowoc Indigo Series Technician's Handbook page 211

QuietQube® Models - Analyzing Suction Pressure
The suction pressure gradually drops throughout the
freeze cycle. The actual suction pressure (and drop
rate) changes as the air and water temperature
entering the ice machine changes. These variables
also determine the freeze cycle times.
To analyze and identify the proper suction pressure
drop throughout the freeze cycle, compare the
published suction pressure to the published freeze
cycle time.
Analyze discharge pressure before analyzing
NOTE:
suction pressure. High or low discharge pressure may
be causing high or low suction pressure.
Step
1. Determine the ice machine operating
conditions. *Temperature of air entering the
condenser. Look up and determine the
published suction pressure.
2. Perform an actual suction pressure check at the
beginning, middle and end of the Freeze cycle.
*Freeze cycle begins when the water pump
starts
3. Compare the actual Freeze cycle suction
pressure (step 2) to the published Freeze cycle
pressure. Determine if the suction pressure is
high, low or normal.
Part Number Preliminary 6/11
Procedure
211