Manitowoc Marine Q 1800 Service Manual page 4

Refrigeration System
Sequence of Operation
Self-Contained Water-Cooled Models .........................................................................................................28
Operational Analysis (Diagnostics)
General............................................................................................................................................................29
Before Beginning Service ..............................................................................................................................30
Ice Production Check ....................................................................................................................................30
Installation/Visual Inspection Checklist ......................................................................................................31
Water System Checklist ................................................................................................................................31
Ice Formation Pattern ...................................................................................................................................32
Safety Limits...................................................................................................................................................34
Hot Gas Valve Temperature Check .............................................................................................................37
Analyzing Discharge Pressure During Freeze or Harvest Cycle
Procedure..................................................................................................................................................38
Freeze Cycle Discharge Pressure High Checklist .................................................................................38
Freeze Cycle Discharge Pressure Low Checklist ..................................................................................38
Analyzing Suction Pressure During Freeze Cycle
Procedure..................................................................................................................................................39
Freeze Cycle Suction Pressure High Checklist .....................................................................................40
Freeze Cycle Suction Pressure Low Checklist ......................................................................................40
How to Use the Refrigeration System Operational Analysis Tables.........................................................41
Refrigeration System Operational Analysis Table
Dual TXV..................................................................................................................................................42
Pressure Control Specifications and Diagnostics
High Pressure Cutout (HPCO) Control.......................................................................................................43
Cycle Time/24 Hour Ice Production/Refrigerant Pressure Charts
Q1800 ..............................................................................................................................................................44
Refrigerant Recovery/Evacuating and Recharging
Normal Self-Contained Model Procedures..................................................................................................45
System Contamination Cleanup ...................................................................................................................47
Replacing Pressure Controls Without Removing Refrigerant Charge ....................................................49
Filter-Driers....................................................................................................................................................51
Total System Refrigerant Charges ...............................................................................................................51
Refrigerant Definitions..................................................................................................................................52
Refrigerant Re-Use Policy.............................................................................................................................53
HFC Refrigerant Questions and Answers ...................................................................................................54
Table of Contents