Analyzing Suction Pressure - Manitowoc QR0670C Technician Manual

Freeze Cycle Discharge Pressure Low Checklist
Problem
 Cause
Improper Installation
 Refer to "Installation/Visual Inspection Checklist"
Improper Refrigerant Charge
 Undercharged
 Wrong type of refrigerant
Other
 Non-Manitowoc components in system
 High side refrigerant lines/component restricted
(before mid-condenser)
 Defective head pressure control valve
 Defective fan cycle control (Not used on CVD675/
CVD1476)
 Water regulating valve incorrectly set (CVD1476
only)
NOTE: Do not limit your diagnosis to only the items
listed in the checklists.

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.
NOTE: Analyze discharge pressure before analyzing
suction pressure. High or low discharge pressure may
be causing high or low suction pressure.
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