Refrigeration System

Section 7

 

 

Safety Limit #1

Refer to previous page for safety limit operation.

Freeze time exceeds 60 minutes for 6 consecutive freeze cycles.

Possible Cause

Check/Correct

Improper installation

See “Installation/Visual Inspection Checklist”

Water system

Low water pressure [20 psi (138 kPa) min.]

 

High water pressure [80 psi (552 kPa) max.]

 

High water temperature (90°F/32.2°C max.)

 

Clogged water distribution tube

 

Dirty/defective water fill valve

 

Dirty/defective water dump valve

 

Defective water pump

 

Loss of water from sump area

Electrical system

Low incoming voltage

 

Ice thickness probe out of adjustment

 

Harvest cycle not initiated electrically

 

Contactor not energizing

 

Compressor electrically non-operational

Miscellaneous

Restricted condenser airflow

 

High inlet air temperature (Self-Contained -110°F/43.3°C max.;

 

Remote - 120°F/49°C max.)

 

Condenser discharge air recirculation

 

Dirty condenser filter

 

Dirty condenser

 

Restricted condenser water flow

 

Low water pressure [20 psi (138 kPa) min.]

 

High water temperature (90°F/32.2°C max.)

 

Dirty/defective water regulating valve

 

Water regulating valve out of adjustment

Refrigeration system

Improper refrigerant charge

 

Non-Manitowoc components

 

Defective harvest valve

 

Defective compressor

 

TXV starving or flooding (check bulb mounting)

 

Non-condensables in refrigeration system

 

Plugged or restricted high side refrigerant lines or component

SAFETY LIMIT NOTES

Because there are many possible external problems, do not limit your diagnosis to only the items listed in this chart.

A continuous run of 100 harvests automatically erases the safety limit code.

The control board will store and indicate only one safety limit – the last one exceeded.

If the toggle switch is moved to the OFF position and then back to the ICE position prior to reaching the 100-harvest point, the last safety limit exceeded will be indicated.

If a Safety Limit light did not flash prior to the ice machine restarting, then the ice machine did not stop because it exceeded a safety limit.

7-10

Part Number 80-1634-3

Page 76
Image 76
Manitowoc Ice S1800 service manual Safety Limit Notes, Possible Cause Check/Correct