Maxx Ice MIM250 User manual

1
Automatic Ice maker
Service manual
MIM250

2
Table of contents
Installation Guidelines ---------------------------------------------------------3
How the Ice Maker Works ----------------------------------------------------4
Water System --------------------------------------------------------------------5
Wiring Connections and Controller ------------------------------------------8
Exploding Drawing -------------------------------------------------------------11
TroubleShooting ----------------------------------------------------------------13
Before Maintenance ------------------------------------------------------------13
Basic Checking ------------------------------------------------------------------13
TroubleshootingGuide ----------------------------------------------------------14
Adjustment and Replacement -------------------------------------------------19
Advanced component troubleshooting techniques --------------------------20
Spare parts list ------------------------------------------------------------------- 26

3
Installation Guidelines
Note: Installation should be performed by a trained Service Technician.
For proper operation of the ice machine, the following installation guidelines must be followed.
Failure to do so may result in loss of production capacity, premature part failures, and may void all
warranties.
Ambient Operating Temperatures
Minimum Operating Temperature: 50°F (10°C)
Maximum Operating Temperature 100°F (38°C).
Note: These products are not designed for outdoor installation.
Incoming Water Supply
Minimum incoming water temperature: 40°F (5°C)
Maximum incoming water temperature: 90°F (32°C)
Minimum incoming water pressure: 15 psig
Maximum incoming water pressure: 80 psig
Note: If water pressure exceeds 80 psig, a water pressure regulator must be installed.
Drains: Route bin drain, purge drain and water condenser drain individually to a floor drain. The
use of condensate pumps for draining water on equipment producing over 200 lbs./day is not
recommended by Manufactor. We assumes no responsibility for improperly installed equipment.
Water Filtration
A water filter system should be installed with the ice machine.
Clearance Requirements
Self contained air cooled ice machines must have a minimum of 6 inches (15cm) of clearance at the
rear, top, and sides of the ice machine for proper air circulation. Since undercounter machines
breathe from the front, top and side clearances are minimal.
Stacking
If the ice machines are to be stacked, refer to the instructions in the stacking kit. We does not
endorse stacking aircooled ice machines.
Dispenser Application
A thermostatic bin control kit must be installed if the ice machine is placed on a dispenser. A bin
top may or may not be required.
Ice Maker Maintenance
Maintenance Procedure
1. Clean the icemaking section per the instructions below. Cleaning should be performed a
minimum of every 6 months. Local water conditions may require that cleaning be performed more
often.
2. Check ice bridge thickness. Proper thickness should be 1/16-1/8’’.
3. Check water level in trough. See troubleshooting for proper water level and adjustment.
4. Clean the condenser to insure unobstructed air flow.
5. Check for leaks of any kind: Water, Refrigerant, Oil, Etc.
6. Check the bin switch for proper adjustment.
7. Check all electrical connections.

4
8. Oil the fan motor if the motor has an oil fitting.
Cleaning and Sanitizing
Harvest problems may occur if the following procedures are not performed every 6 months.
1. Remove the ice machine front panel.
2. Make sure that all the ice is off of the evaporator. If ice is being made, wait for cycle completion,
then turn the machine “OFF” at the selector switch.
3. Remove or melt all ice in the storage bin.
4. Add recommended amount of approved ice machine cleaner to the water trough according to
label instructions on the container.
5. Initiate the clean cycle at the controller board switch by turning on the machine and activating the
switch marked as “CLEAN”. Note: This must be done within 3 minutes of turning the machine
“ON”. Allow the cleaner to circulate for approximately 15 minutes to remove mineral deposits.
6. After 15 minutes (or 30 minutes automatically), stop the process and drain the sump. Refill with
clean water run another 5 minutes and drain again. Fill the trough with fresh incoming water.
7. Terminate the wash cycle at the switch by placing the switch in the “OFF” position. Remove the
splash curtain (if available) and inspect the evaporator and water spillway (the plastic top of the
evaporator) to assure all mineral residue has been removed.
8. If necessary, wipe the evaporator, spillway and other water transport surfaces with a clean soft
cloth to remove any remaining residue. If necessary, remove the water distribution tube,
disassemble and clean with a bottlebrush. Reassemble all components and repeat steps 4 through 7
as required to remove residue.
9. Turn OFF ice machine water supply and clean the water trough thoroughly to remove all scale or
slime buildup. If necessary, remove the water trough to reach all splash areas and float.
10. Prepare 1½ to 2 gallons (5.7 to 7.5 liters) of approved (EPA/FDA) sodium hypochloride food
equipment sanitizer to form a solution with 100 to 200 ppm free chlorine yield.
11. Add enough sanitizing solution to fill the water trough to overflowing and activate the switch to
the “CLEAN” position and allow circulation to occur for 10 minutes and inspect all disassembled
fittings for leaks. During this time, wipe down all other ice machine splash areas, plus the interior
surfaces of the bin, deflector and door with the remaining sanitizing solution. Inspect to insure that
all functional parts, fasteners, thermostat bulbs (if used), etc. are in place.
12. After 3 minutes, stop the process and drain the sump. Refill with clean water run another 5
minutes and drain again. Fill the trough with fresh incoming water.
13. Place the switch to the “ON” position and replace or close the panel. Discard the first two ice
harvests.
How the Ice Maker Works
Refer to the Operation section of the User’s Manual (pages 12 to 14) for a clear description of how
the ice maker makes ice and uses water.
There are 3 systems: the Cooling System, the Water System and the Electrical System.

5
Cooling System

6
ITEM NO
DESCRIPTION
1
Compressor
2
Discharge tube
3
Cu three ways
4
Condenser
5
Drier and filter
6
Capillary tube
7
Connection tube
8
Hot gas valve
9
Hot gas tube
10
Evaporator (Ice Mold)
11
Fan blade(φ200X28°)
12
Suction pipe
13
Motor 5W
14
Motor 10W
15
Temperature sensor of the evaporator
16
Temperature sensor of the condenser
17
Controller
During the icemaking stage, the hot gas solenoid valve is closed. The hot refrigerant gas is
pumped out of the compressor to the condenser. The hot gas is cooled by fanforced air to cool the
liquid refrigerant after passing through the condenser. The drier and filter reduce possible dirt and
moisture in the refrigerant. The refrigerant expands in the evaporator cooling it so ice will form
while in the presence of water. Low pressure refrigerant gas returns to the compressor from the
evaporator where the cycle continues.
During the ice harvest stage, the solenoid valve is open. The hot refrigerant gas is pumped out of
the compressor to the evaporator through the hot gas valve. As the hot gas is not cooled by the
condenser, the refrigerant warms the evaporator. Ice in contact with the evaporator begins to melt
on the back side. The ice gradually ice slides off of the evaporator and drops to the storage bin.

7
Water System
ITEM NO.
DESCRIPTION
1
Water supply tube
2
Water inlet connector
3
Nut of water inlet tube
4
Supporting tube
5
Water pump inlet tube
6
Floater valve
7
Water trough
8
Water pump
9
Water pump outlet tube
10
Ice slideway
11
Water distribution tube
12
Evaporator (Ice Mold)
13
Magnetism switch
14
Gasket
15
Screw cap
When the water inlet is connected with the main water supply, water will fill the trough through the
float valve until the water level in the trough closes the valve. During the icemaking stage, water is
pumped from the water trough to the water distribution tube. The distributed water flows over the

8
surface of the cold evaporator where the purest water is converted to ice. The unfrozen water
returning to the trough. At the end of freeze cycle and during harvest, the water dump valve is
opened and the mineral laden remaining water is pumped down the drain.
Wiring Connection :

9
Circuit Description
1. Electrify Status For The First Time
As the icemaker is properly installed. switch on the water tap, let the water trough full (reach on the
level), then turn the Power switch to the ON position on the back panel. The icemaker will start
working automatically
In this status, the time is fixed about 3 minutes. This function is also helpful to protect the
compressor avoiding restart within 3 minutes.
At this status, the White, Green, Yellow and Red LEDs are light together.
2. Ice-making Status
The compressor, motor fan and pump are powered on. The hot gas solenoid valve is powered off.
When this green LED is lit, the unit is working in the ice making mode controlled by a temperature
probe on the evaporator. When the green LED is flashing, the unit is working in the ice making
mode controlled by a fixed timer.
The fan motor is also controlled by a condenser sensor. When the ambient temperature is too lower,
the motor fan stop working for good condensation to refrigerant.
3. Ice Harvest Status
The pump is powered off. The hot gas solenoid valve, compressor and motor fan is powered on.
The fan motor is also controlled by a condenser sensor. When the ambient temperature is too lower,
the motor fan stop working for good condensation to refrigerant.
The Yellow LED indicates the ice harvest status.
4. Ice Full Status And Cold Preservation Stage
If the ice bin is fulfilled with ice, the machine stops making ice and turn to cold preservation stage
automatically.
In this status, the compressor works regularly to keep the lower temperature for lower ice melting.
The rest of the electric components are powered off. The WHITE LED indicates the ice full status
and the GREEN AND YELLOW LEDs together indicates the cold preservation status .
5. Cleaning Status
Turn the machine CLEAN SWITCH at the CLEAN in 3 minutes after the POWER SWITCH is
turned on, the machine turn to Cleaning Status. At this status, the pump is powered on. Compressor,
motor fan and are powered off. The GREEN and YOLLOW LEDs are flashing together. To stop the
cleaning mode, turn the machine “OFF” at the Power switch or it will turned off automatically after
30 minutes.
NOTE: In order to start the Clean Status the power switch must be on. The CLEAN switch must be
turned in 3 before the COMPRESSOR starts. To clean, it is no use turning the CLEAN switch when
machine is in ice-making status or ice-harvest status.
Controller box:
Instructions for LEDs and buttons:
1. White LED: Ice full indicator light.
When this LED is lit, the ice storage bin is full of ice or there is something between the ice-full
sensor and the evaporator. The unit will stop making ice. When ice cubes are taken out of the ice
storage bin making the ice-full probe free, the white LED will keep flashing for 3 minutes. Then the
unit will restart and return to the ice making mode.
2. Green LED: Ice making indicator light.
When this LED is lit, the unit is working in the ice making mode controlled by a temperature probe
on the evaporator. When the green LED is flashing, the unit is working in the ice making mode
controlled by a fixed timer.
3. Yellow LED: Ice harvest indicator light.
When this LED is lit, the unit is working in the ice harvest mode controlled by ice-full probe.

10
When green LED and yellow LED is lit, it means the unit is working in the cold preservation
stage .
4.Red LED: power indicator light.
The power is on when the red LED is lit.
5. Mode button:
Mainly for service. When this button is pressed, it can change from ice making mode to ice harvest
mode, or from ice harvest mode to ice making mode. You can judge the mode from the status of the
green and yellow LEDs.
6. Ice size adjust:
1. Press and hold the “Clean” button and the “Mode” button together for at least 3 seconds. The
unit will enter the Ice Size Adjustment mode. The “ICE” LED (green) will be blinking
continuously during the ice size adjustment.
2. While in the Ice Size Adjustment mode, press the “Clean” button or the “Mode” button for the
desired ice size.
Smaller ice setting:
By pressing the “Clean” button, you can decrease the size of the ice cubes. The “FULL” LED (red)
will flash as you lower the ice size and will finally be blinking at the setting of smallest ice size.
Larger ice setting:
By pressing the “Mode” button, you can increase the size of the ice cubes. The “HARVEST” LED
(yellow) will flash as the larger size is set and will blink when the setting of largest ice size has been
reached.
After 10 seconds without any operation, the unit will automatically memorize the current state and
return to the previous mode.
NOTE: If during the ice size adjustment, the “BIN FULL”, “ICE” and “HARVEST” LEDS blink
all at once, this indicates that the unit is in the default factory setting of the ice size adjustment.

11
Exploding Drawing

12
Item No.
Description
2
Ice scoop
3
Top panel
7
Drain nut
9
Condenser
10
Hot gas valve body (EVU3)
11
Hot gas valve coil（042N4212）
16
Compressor
17
Compressor starting device component
18
Water trough
22
Floater valve
23
water inlet pipe screw
24
Drain valve
25
Water out tube of pump
26
Water pump
27
Water inlet
28
Condenser sensor
29
Evaporator sensor
31
Water sprinkler
32
Evaporator (Ice Mold)
33
Ice slideway
35
Wiring harness
36
Magnetism switch
38
Power plug
41
EBM motor 5W
42
Fan blade (φ200X28°)
43
EBM motor 10W
49
Power switch
50
Clean switch
51
Under louver
52
Door
54
Locked screw(Block screw)
55
Foot
57
Drier
60
15A fuse of controller
61
Control box

13
Troubleshooting
Before Maintenance
1. Be sure the electrical supply is 115 VAC, 60Hz, 15A and is properly grounded to protect
maintenance personnel against electrical shock.
2. Are any electrical leads loose? Danger of short circuit? If so, disconnect power.
Basic Troubleshooting
Some problems can be pinpointed through the service technician’s senses of hearing, sight and
touch. Examples are listed below.
Listen
Listen to the user’s description of how the ice maker was operating, especially the depiction of
unusual phenomena. Ask how the unit was operating before the user called for service and try to
deduce the defect from the comments.
Does the machine sound normal when it is running (like a window air conditioner)?
Look
Check the cooling system tubing, especially the welded joints. If some oil can be seen, the gas
may be leaking resulting in less than the normal amount of ice is being produced.
Is the cycle of the icemaking and ice harvesting normal (Does water run, is the fan running and
is the evaporator getting cold enough)?
Check the water system especially at the connections. Are there any water leaks?
Check the flow of water through the water filter and if not, replace the water filter.
Check if the ice maker was installed according to the user’s manual (level and air space).
Inspect the ice maker to see if it needs to be cleaned. Please note, cleaning a dirty ice maker is
not a warranty repair!
Feel
Touch the tubing at the evaporation weld, feeling the temperature. During the icemaking stage,
it should feel cold. During the ice harvest stage, it should feel hot.
If appropriate, touch the capillary tube or TXV tubing (near the drier). It should feel warm
during the ice making stage.
Troubleshooting Guide
This troubleshooting guide in the user manual should be read before this guide. Be sure only when
the trouble shooting in user manual can’t help you solve the problem, turn to this guide.
Troubleshooting Guide
ELECTRICALSHOCK HAZARD
Disconnect Electrical Power Before
Beginning Removal of Parts

14

15

16

17

18

19
Adjustment and Replacement
Replace Control box, fuse and the sensor of temperature
Replacing Control Box Fuse and Temperature Sensor
Remove the rear cover and the louvered front panel or the side panel on a modular unit.
Locate the electronic control box in the unit.
Carefully pull out the temperature sensors (one at the evaporator, another at the condenser).
Loosen the screws holding the control box, replace with a new one. Reverse the foregoing steps
to reassemble.
If you need to replace the fuse, open the front panel of the control box and you will find this
figure:
If you need to replace a temperature sensor, pull out the sensor, open the panel of the control
box, pull out the other end of the sensor, replace with a new one. Reverse these steps to reassemble.
Replacing the water pump
Disconnect electrical power.
Remove the front cover.
Unplug the lines connected with the water pump, including the water outlet tube of the pump.
Loosen the screws. Replace the pump with a new one.
Reverse the above steps to reassemble.
Replacing the cooling system components
To replace the condensing components, see the Cooling System figure.
1. Replacing the compressor and the compressor kit (includes relay, thermal protect)
If only the compressor kit needs to be
replaced, remove the top panel and left
panel, locate the compressor, take off
the clip, replace the defective
components.
Reverse the above steps to reassemble.
ELECTRICAL SHOCK HAZARD
Disconnect electrical power before
beginning removal of parts.
If the compressor needs to be replaced, remove the top cover and locate the compressor.
Unplug lines and remove ground line, open the Process/Suction, evacuate refrigerant, take out
compressor, replace with a new one, join together, then recover refrigerant, weigh in the charge on
the nameplate.
Reverse the above steps to reassemble.
2. Replacing the fan motor and fan blade
Remove the top and right panels.
Locate the fan motor, unplug the lines connected with the fan motor, loosen the screws of the
holding bracket and fan motor bracket, remove the damaged unit and replace with a new one.
Reverse the above steps to reassemble.
ELECTRICALSHOCK HAZARD
Disconnect Electrical Power Before
Beginning Removal of Parts

20
3. Replacing the hot gas valve, drier and evaporator
Remove the top panel.
Locate the drier and hot gas valve, open weld, replace the drier and hot gas valve, weld, recover
refrigerant, evacuate and weigh in the charge on the nameplate.
Reverse the above steps to reassemble.
If needed, replace the evaporator.
Remove the front and top panels, locate the evaporator, open the Process/Suction, open the two
welds, replace with a new evaporator. Recover refrigerant, evacuate and weigh in the charge on the
nameplate.
Reverse the above steps to reassemble.
ADVANCED COMPONENT TROUBLESHOOTING TECHNIQUES
Refrigeration System
Refrigerant Cycle and Components
Before diagnosing the refrigeration system, it is very important that the refrigeration charge be
correct. Whenever the refrigeration system has been opened, the filterdrier must be replaced and the
proper refrigerant charge must be weighed in.
Refrigerant Pressures
The suction pressure at the beginning of the freeze cycle can vary +/10 psi (.7 bar) depending on
operating conditions. Pressures less than this may indicate an undercharge. The discharge pressure
on air cooled units will vary with ambient conditions.
Refrigerant in a gas state is pumped throughout the refrigeration system by a hermetic compressor
to the condenser. Heat is removed from the refrigerant either by forced air movement through an
aircooled condenser or transferring heat from the refrigerant to water through a watercooled
condenser. The refrigerant changes to a liquid when cooled. The refrigerant in a liquid state passes
through a filter drier.
The filter drier traps small amounts of moisture and foreign particles from the system. The filter
drier must be replace whenever the refrigeration system is opened or if the refrigerant has been
completely lost.
Compressor
The compressor runs during the entire cycle. If the valves in the compressor are damaged, the
compressor will be unable to pump refrigerant efficiently. Damaged valves may be the result of
another problem in the refrigeration system such as liquid refrigerant returning to the compressor or
high head pressure. When a compressor is replaced it is important that the refrigeration charge be
weighed in and the system checked for proper operation to prevent a repeat failure.
An inefficient compressor will usually have a higher than normal suction pressure at the end of the
cycle. The freeze cycle will be longer than normal and/or the harvest cycle may be excessively long.
Check the compressor amperage draw 5 minutes into the freeze cycle. If the amp draw is less than
70% of rated full load amps, the compressor may be inefficient. These symptoms may also be
caused by other problems, therefore it is important to use the troubleshooting charts when
diagnosing a problem.
The air condenser is located in the back of the cabinet. Air is pulled through the condenser by a fan
motor and discharged through the right hand side panel. The Undercounter air intake and discharge
is through the front panel.
Do not block airflow as it will cause premature failure of the machine and will void the
warranty.