Temperature Control; Defrost Timer - Maytag AFU1202BW Service

Component Testing
!
WARNING
power to be connected. When removing any wiring from terminals they must be replaced on the same terminals.
Ensure all ground wires are connected before certifying unit as repaired and/or operational.
On no-defrosting models, check control feeler tube
cover to verify air is allowed to pass freely under it
and circulate around the feeler tube.
If compressor continues to run, disconnect wire from one
control terminal. If compressor stops, control has failed
and must be replace. If compressor still runs, check
cabinet wiring for a short circuit.

Temperature Control

Freezer temperature should vary considerably by
changing control knob setting. If not, check control cut-in
and cut-out temperatures as follows:
1. On no-defrost models, disconnect control feeler tube
cover from food liner side by pulling straight out at its
center. Fasten a thermocouple to feeler tube with a
rubber band.
Attaching Thermocouple to Feeler Tube
No Defrost Models
On refrigerated shelf models, use a few drops of
water to freeze the bulb on thermocouple to the
freezer shelf near control feeler tube thermal contact
point.
2. Set control halfway between "Off" and "MAX.-Cool".
Close cabinet door and wait for compressor to run
through 2 or 3 complete cycles.
3. If cut-in and cut-out temperatures are not within 2 or 3
degrees of those specified below replace the control.
Temperature Control
Auto Warm Calibration Pt.
Defrost Cut-in
45°
cut-in
15 ± 3 −6.8 ± 2 −18.4 ± 2
Yes
14 ± 3 +8 ± 2
No
©2004 Maytag Services
Cold cut-out
Cut-out
135° 315°
−29.2 ± 2
−8 ± 2 −22 or below
MID 180°
16023585
To avoid risk electrical shock, personal injury, or death,
always disconnect electrical power source to the freezer
before attempting to service, unless test procedures require

Defrost Timer

Freezer coil defrost system is actuated by an electric
timer which is located on the rear leg of the cabinet.
Timer initiates defrost cycle every twelve hours of
compressor running time, regardless of control setting or
of interior temperatures.
1st Click —Timer switches off compressor and freezer
fan circuit. At the same time it energizes the defrost
circuit for approximately 30 minutes.
Once defrost heater warms coil header to approximately
52 degrees, defrost thermostat contacts open to shut off
the heater.
Defrost Timer Circuits
Line
(white)
3
Timer
1
Line
(red)
2nd Click—Timer switches off defrost circuit and starts
compressor and freezer fan to end the defrost cycle.
Compressor, freezer fan, and defrost timer are now
controlled by the temperature control for a period of
approximately 12 hours, after which a new defrost cycle
begins.
Line
(white)
3
Timer
1
Line
(red)
To compressor
2
4
Control
To compressor
2
4
Control
19