Manitowoc Undercounter Calling For Service

Before Calling for Service
Checklist
If a problem arises during operation of your ice machine, follow the checklist below before calling for service. Routine adjustments and maintenance procedures are not covered by the warranty.
Ice machine does not operate.
No electrical power to the ice machine.
Replace the fuse/reset the breaker/turn on the main switch/plug power cord into receptacle.
ON/OFF/ WASH toggle switch set improperly.
Move the toggle switch to the ON position.
Damper in open position (down).
Damper must be in upright position and capable of swinging freely.
Ice machine stops, and can be restarted by moving the toggle switch to OFF and back to ICE.
Safety limit feature stopping the ice machine.
Refer to “Safety Limit Feature” on the next page.
Ice machine does not release ice or is slow to harvest.
Ice machine is dirty.
Clean and sanitize the ice machine. See pages 4-1.
Ice machine is not level.
Level the ice machine. See page 2-4.
Low air temperature around ice machine (air-cooled models).
Air temperature must be at least 35°F (1.7°C).
Water regulating valve leaks in harvest mode (water-cooled models).
Replace water regulating valve.
Ice machine does not cycle into harvest mode.
The six-minute freeze time lock-in has not expired yet.
Wait for freeze lock-in to expire.
Ice thickness probe is dirty.
Clean and sanitize the ice machine. See pages 4-1.
Ice thickness probe wire is disconnected.
Connect the wire.
Ice thickness probe is out of adjustment.
Adjust the ice thickness probe. See page 3-5.
Uneven ice fill (thin at top of evaporator).
Ice quality is poor (soft or not clear).
Poor incoming water quality.
Contact a qualified service company to test the quality of the incoming water and make appropriate filter recommendations.
Water filtration is poor. Replace the filter.
Ice machine is dirty. Clean and sanitize the ice machine. See pages 4-1.
Water siphon is not working. Check the water siphon system.
Water softener is working improperly (if applicable). Repair the water softener.

Ice machine produces shallow or incomplete cubes, or the ice Ice thickness probe is out of adjustment.
Adjust the ice thickness probe. See page 3-5. fill pattern on the evaporator is incomplete.
Water trough level is to high or too low. Check the water level. See page 3-4.
Water float valve filter screen is dirty. Remove and clean the filter screen. See page 4-4.
Water filtration is poor. Replace the filter.
Hot incoming water. Connect the ice machine to a cold water supply. See page 2-7.
Water float valve is not working. Remove the water float valve and clean it. See page 4-4.
Incorrect incoming water pressure. Water pressure must be 20-80 psi (137.9 - 551.5 kPA).
Ice machine is not level. Level the ice machine.

Low ice capacity.
Water float valve filter screen is dirty. Remove and clean the filter screen. See page 4-8.
Incoming water supply is shut off. Open the water service valve.
Water float valve stuck open or leaking. Remove the water float valve and clean it. See page 4-4.
The condenser is dirty. Clean the condenser. See page 4-9.
High air temperature around ice machine (air-cooled models).
Air temperature must not exceed 110°F (43.3°C). Inadequate clearance around the ice machine.
Provide adequate clearance.

Objects stacked around ice machine, blocking airflow to condenser (air-cooled models).
Remove items blocking airflow.
Safety Limit Feature
In addition to the standard safety controls, your Manitowoc ice machine features built-in safety limits that will stop the ice machine if conditions arise which could cause a major component failure.
Before calling for service, re-start the ice machine using the following procedure:
1. Move the ON/OFF/ WASH switch to OFF and then back to ON.
A. If the safety limit feature has stopped the ice machine, it will restart after a short delay. Proceed to step 2.
B. If the ice machine does not restart, see “Ice machine does not operate” on the previous page.
2. Allow the ice machine to run to determine if the condition is reoccurring.
A. If the ice machine stops again, the condition has reoccurred. Call for service.
B. If the ice machine continues to run, the condition has corrected itself. Allow the ice machine to continue running.

In addition to standard safety controls, the control board has two built in safety limit controls which protect the ice machine from major component failures.
Safety Limit #1: If the freeze time reaches 60 minutes, the control board automatically initiates a harvest cycle. If three consecutive 60-minute freeze cycles occur, the ice machine stops.
Safety Limit #2: If the harvest time reaches 3.5 minutes, the control board automatically returns the ice machine to the freeze cycle. If three consecutive 3.5 minute harvest cycles occur, the ice machine stops.
Safety Limit Stand-By Mode:
The first time a safety limit shut down occurs, the ice machine turns off for 60 minutes (Stand-by Mode). The ice machine
will then automatically restart to see if the problem reoccurs. During the Stand-By Mode the harvest light will be flashing continuously and a safety limit indication can be viewed. If the same safety limit is reached a second time (the problem has reoccurred) the ice machine will initiate a safety limit shut down and remain off until it is manually restarted. During a safety
limit shut down the harvest light will be flashing continuously.
Determining Which Safety Limit Stopped The Ice Machine
When a safety limit condition causes the ice machine to stop, the harvest light on the control board continually flashes on
and off. Use the following procedures to determine which safety limit has stopped the ice machine.
1. Move the toggle switch to OFF.
2. Move the toggle switch back to ON.
3. Watch the harvest light. It will flash one or two times, corresponding to safety limits 1 and 2, to indicate which safety limit stopped the ice machine.
After safety limit indication, the ice machine will restart and run until a safety limit is exceeded again. Safety Limit Notes
• A safety limit indication is completed before the water pump starts. Water contacting the ice thickness probe in the freeze cycle will cause the harvest light to flash. Do not mistake a harvest light flashing in the freeze cycle with a safety limit
indication.
• 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 ON position prior to reaching the 100-harvest
point, the last safety limit exceeded will be indicated.
• If the harvest light did not flash prior to the ice machine restarting, then the ice machine did not stop because it exceeded a safety limit.

Freeze time exceeds 60 minutes for 3 consecutive freeze cycles.
Possible Cause
Improper installation
• See “Installation Instructions” Section 2 of this manual Water system
• Low water pressure (20 psi minimum.)
• High water pressure (80 psi maximum.)
• High water temperature (90°F/32.2°C maximum.)
• Clogged water distribution tube
• Dirty/defective water float valve
• Loss of water from sump area
• Defective water pump
Electrical system
• Ice thickness probe out of adjustment
• Harvest cycle not initiated electrically
• Compressor relay not energizing
• Compressor electrically non-operational
Restricted condenser air flow (air-cooled models)
• High inlet air temperature (110°F/43.3°C maximum.)
• Condenser discharge air recirculation
• Dirty condenser filter
• Dirty condenser fins
• Defective fan cycling control
• Defective fan motor
Refrigeration system
• Non-Manitowoc components
• Improper refrigerant charge
• Defective hot gas valve
• Defective compressor
• TXV starving or flooding (check insulation and bulb mounting)
• Non-condensables in refrigeration system
• Plugged or restricted high side refrigerant lines or component
Safety Limit #2
Harvest time exceeds 3.5 minutes for 3 consecutive harvest cycles.
Possible Cause
Check/Correct
Improper installation
• See “Installation Instructions” Section 2 of this manual Water system
• Water area (evaporator) dirty
• Water freezing behind evaporator
• Low water pressure (20 psi minimum.)
• Loss of water from sump area
• Clogged water distribution tube
• Dirty/defective water float valve
• Defective water pump
Electrical system
• Ice thickness probe out of adjustment
• Ice thickness probe dirty
• Bin switch defective
• Premature harvest
Refrigeration system
• Non-Manitowoc components
• Improper refrigerant charge
• Defective hot gas valve
• TXV flooding (check insulation and bulb mounting)
• Defective fan cycling control
Because there are many possible external problems,
do not limit your diagnosis to only the items listed in these charts.