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We have a Maytag refrigerator that was not cooling in the fresh food compartment. We have no technician diagnostic sheet with this unit. We replaced the thermistor the air damper is now open but it is freezing the fresh food compartment. The freezer is fine. We checked the unit found damper closed.
The customer called back 2 days later and the fresh food is now freezing everything.
There are no problems with the defrost system.
The evaporator fan motor is fine.

Thanks in advance.

Model Number
MFF2557HEB
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Run through the diagnostic mode below to see what error codes you have stored. I suspect the Jazz control if the unit will pass all of the diagnostic tests, including the thermister and damper checks.

Programming Mode:
Note: The Program Code is located on the Serial Plate on this unit after the word Code.
1. Open the Fresh Food door and hold the Fresh Food door light switch closed while pushing the Freezer
Temperature Down Key pad 3 times consecutively.
Note: The 3 Keystrokes must be done consecutively and within 10 seconds.
2. Release the Fresh Food door light switch.
3. The control will display PE to confirm entry into the programming mode.
P
Freezer Refrigerator
E
4. Entry is confirmed by pressing the Freezer Down key once more.
Note: All control functions will be turned off (Compressor, Defrost, Evaporator Fan, the damper will
remain in its current position).
5. The control will display the current Program Code. This value should be validated with the Program Code
printed on the unit serial plate.
2
Freezer Refrigerator
5
Note: If the Program Code is correct, the Programming Mode is exited by closing the Refrigerator door(s).
6. To set the desired Program Code number press the Freezer and Refrigerator Up keys. The
corresponding digit will be advanced with each key press.
7. Once the desired Program Code is displayed, press the Freezer Down Key until the Program Code
begins flashing indicating it has been saved.
Note: If you attempt to enter an invalid Program Code the control will not save the new code, but will flash the old
code and this will be displayed. (The unit will NOT run with a Program Code of 00).
8. Once the Program Code has been saved the Programming Mode is exited by closing the Refrigerator
door(s). If the new code is incorrect this process should be repeated after closing the Refrigerator door(s).
The Programming mode can be exited at any time by closing the Refrigerator Door(s).
Defrost Operation:
The Control Board adapts the compressor run time between defrosts to achieve optimum defrost intervals by
monitoring the length of time the defrost heater is on.
After initial power up, defrost interval is 4 hours compressor run time. Defrost occurs immediately after the 4 hours.
Note: Once unit is ready to defrost there is a 4 minute wait time prior to the beginning of the defrost cycle.
Optimum defrost is 15 minutes. Each additional minute the defrost thermostat remains closed, 1 hr. is subtracted from
the previous defrost interval. Each minute the thermostat opens prior to optimum defrost, it extends the next defrost
interval 1 hr. When defrost thermostat opens there is a 4-6 minute drip time before compressor restarts or Control
Board will terminate defrost at 25 minutes if defrost thermostat has not opened and will reset the defrost interval to the
8 hr. minimum setting.
4 hours of continuous compressor run resets the next defrost interval to 8 hours and will initiate a defrost, if 8 hours of
compressor run time has also occurred.
Forced Defrost Mode:
Power up Refrigeration mode will occur unless both the cold control and defrost terminator are open, in that case the
defrost mode will occur for 2 minutes.
The forced defrost function is performed using the refrigerator display and keypad. Enter the Forced Defrost
Mode by performing the following sequence of events:
1. Hold the refrigerator door light switch closed.
2. Press the Refrigerator Temperature Down keypad 3 times consecutively.
Note: The 3 keystrokes must be consecutive and within 10 seconds.
Service Specifications
March 2006 4 12827952
! WARNING
To avoid risk of electrical shock that can cause death or severe personal injury, disconnect unit from power before
servicing unless tests require power. Discharge capacitors through a 10,000-ohm resistor before handling. Wires
removed during disassembly must be replaced on correct terminals to ensure proper grounding and polarization.
3. Release the refrigerator door light switch.
4. The control will display Fd to confirm entry into the Forced Defrost Mode.
F
Freezer Refrigerator
5. Entry is confirmed by pressing the Refrigerator Down key once more. The unit is off and in the Defrost Mode.
Note: All control functions will be turned off (Compressor, Defrost, Evaporator Fan, the damper will
remain in its current position).
6. The control will default to the short run period test as shown here:
Freezer Refrigerator
S
Note: You can toggle between the (S)hort and (L)ong test mode by pressing the Refrigerator Up Key.
Long Test mode is used for factory test and should not be used in the field.
Freezer Refrigerator
L
7. Once the desired mode is displayed, confirm the forced defrost by pressing the Refrigerator Down Key once.
The defrost will begin immediately and the display will return to a normal operating display with set point values.
4
Freezer Refrigerator
4
8. Close the Refrigerator door(s). You are in the defrost mode.
Note: Forced Defrost mode can be exited at any time prior to step 7 by closing the Refrigerator Door(s).
Service Test Mode:
The service test functions are performed using the refrigerator display and keypad. Enter the Service Test Mode
by performing the following sequence of events:
1. Hold the refrigerator door light switch closed.
2. Press the Refrigerator Temperature Up keypad 3 times consecutively.
Note: The 3 Keystrokes must be done consecutively and within 10 seconds.
3. Release the refrigerator door light switch.
4. The control will display SE to confirm entry into the service mode.
S
Freezer Refrigerator
E
5. Entry to the Service Menu is confirmed by pressing the Refrigerator Up key once more.
6. The control will display its software version for 3 seconds.
2
Freezer Refrigerator
5
7. Following the software revision display the freezer display will read the first test number in the
diagnostic tree. The refrigerator display will be blank.
1
Freezer Refrigerator
Note: All control functions will be turned off (Compressor, Defrost, Evaporator Fan, the damper will
remain in its current position).
8. You are now in the SERVICES TEST operational mode and may use the diagnostic tests.
The Service Test Mode can be exited at any time by closing the Refrigerator Door(s).
Service Specifications
March 2006 5 12827952
! WARNING
To avoid risk of electrical shock that can cause death or severe personal injury, disconnect unit from power before
servicing unless tests require power. Discharge capacitors through a 10,000-ohm resistor before handling. Wires
removed during disassembly must be replaced on correct terminals to ensure proper grounding and polarization.
Service Test 1 – Defrost Thermostat & Defrost Circuit Test
When selected this test will display the state of the defrost thermostat. In order to perform this test the defrost heater will
be energized. The test is activated and deactivated using the Refrigerator Up key. Once activated, this test must be
deactivated to move to another test number. The Freezer Up / Down keys allow selection of the test to be
performed.
This test also allows observation and measurement of proper defrost function. You can observe defrost heat and voltages
while the test is activated.
1
Freezer Refrigerator
O
DEFROST THERMOSTAT OPEN
1
Freezer Refrigerator
S
DEFROST THERMOSTAT SHORTED (CLOSED)
Service Test 2 – Compressor/Condenser Fan Test
When selected and activated this test will operate the Compressor/Condenser Fan circuit. You should evaluate proper
operation of the compressor and condenser fan. The Refrigerator Up key will toggle between “O” / “F” (ON & OFF)
the compressor drive circuit. The test must be “deactivated” or in the OFF position to move to another test selection.
2
Freezer Refrigerator
O
2
Freezer Refrigerator
F
OBSERVE COMPRESSOR & CONDENSER FAN FUNCTION
Service Test 3 – Evaporator/Freezer Fan Test
When selected and activated this test will operate the freezer fan. The Refrigerator Up key will toggle between “O” /
“F” (ON & OFF) the fan drive circuit. You will have to inspect the fan for proper function. The test must be “deactivated” or
in the OFF position to move to another test selection.

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