Section 7
. Refrigeration System
Part Number 80-1558-3
7-11
ANALYZING DISCHARGE PRESSURE
DURING FREEZE OR HARVEST CYCLE
Procedure
1. Determine the ice machine operating conditions:
Air temp. entering condenser
______
Air temp. around ice machine
______
Water temp. entering sump trough
______
2. Refer to Operating Pressure Chart for ice machine
being checked.
Use the operating conditions determined in step 1 to
find the published normal discharge pressures.
Freeze Cycle _______
Harvest Cycle_______
3. Perform an actual discharge pressure check.
4. Compare the actual discharge pressure (step 3) with
the published discharge pressure (step 2).
The discharge pressure is normal when the actual
pressure falls within the published pressure range for the
ice machine’s operating conditions.
Freeze Cycle Discharge Pressure High Checklist
Freeze Cycle Discharge Pressure Low Checklist
NOTE: Do not limit your diagnosis to only the items listed in the checklists.
Freeze Cycle
PSIG (kPa)
Harvest Cycle
PSIG (kPa)
Beginning of Cycle
__________
__________
Middle of Cycle
__________
__________
End of Cycle
__________
__________
Possible Cause
Check/Correct
Improper installation
See “Installation/Visual Inspection Checklist”
Restricted condenser water flow (water-cooled
models)
Low water pressure [20 psi (138 kPa) min.]
High inlet water temperature (90°F/32.2°C max.)
Dirty condenser
Dirty/defective water regulating valve
Water regulating valve out of adjustment
Improper refrigerant charge
Overcharged
Non-condensables in system
Wrong type of refrigerant
Other
Non-Manitowoc components in system
High side refrigerant lines/component restricted (before mid-condenser)
Defective head pressure control valve (remote models)
Possible Cause
Check/Correct
Improper installation
See “Installation/Visual Inspection Checklist”
Improper refrigerant charge
Undercharged
Wrong type of refrigerant
Water regulating valve (water-cooled condensers)
Out of adjustment
Defective
Other
Non-Manitowoc components in system
Defective head pressure control valve (remote models)
Defective fan cycle control
Summary of Contents for S0850M
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