Amana Bottom Mount Refrigerator service manual Adaptive Defrost Operation, Power Up Condition

Electronic Functional Description

As the temperature decreases, resistance increases. As the temperature increases, resistance decreases. An open thermistor or thermistor circuit will result in failure of refrigerator to cool. Shorted thermistor will result in refrigerator to run 100 percent of time except for defrost.

•Freezer temperature setting and thermistor value will determine if compressor/condenser fan and evaporator fan switches are open or closed. Compressor/condenser fan switch must be open for 6 minutes before switch can close again (compressor dwell time).

•Refrigerator temperature setting and thermistor value will determine if fresh food fan switch is to be open or closed.

•Cutout and cutin temperature values must be reached and maintained for 15 seconds before output state will change (digital delay).

Factory set freezer and refrigerator settings Part # 12067101

Frozen			Fresh
Food			Food		Level
Cut-out			Cut-out
F° (C°) ±			F° (C°) ±
	1.5°		1.5°
-10 (-23)			29	(-2)	9
-8 (-22)			31 (-0.6)		8
-6 (-21)			33 (-0.6)		7
-5		(-21)	34	(1)	6
-4		(-20)	35	(2)	5
-3		(-19)	36	(2)	4
-2		(-19)	37	(3)	3
0		(-18)	39	(4)	2
2		(-17)	41	(5)	1
-10 (-23)			----		Max Ref
		----	29	(-2)	Max Frz

•Refrigerator or freezer control calibration can by adjusted.

Adaptive Defrost Operation

•Defrost occurs after predetermined length of compressor run hours. Compressor run time between defrost changes or adapts, depending upon recent history of defrost lengths (time it takes for defrost terminator to open once defrost heater has been turned on). Defrost terminator opens at 55°F (13°C) and closes at 20°F (-7°C).

•Compressor run time between defrost (CRTD) will be one of 3 values under normal operation: CRTD (1), or CRTD (2) or CRTD (3) defined as 8, 12, and 16 hour lengths. If defrost length is low (DT-LO defined as 21 minutes) indicating small frost load CRTD for next defrost cycle is advanced to next level. If defrost length is high (DI - HI defined as 24 minutes) indicating large frost load CRTD for next defrost cycle is lowered to next level. Initial value at power CRTD (0) is 4 hours.

•Vacation mode CRTD equals 96 hours. Vacation mode CRTD is interrupted with door openings. Defrost interval will revert back to the previous interval before Vacation mode.

•Six minute dwell time occurs after defrost terminator opens before compressor and condenser fan motor will operate. Ten minute dwell time occurs after defrost terminator opens before evaporator fan motor will operate.

•Conventional defrost can be selected.

Power Up Condition

Nine temperature indicators will flash after refrigerator is powered up. Refrigerator begins normal operation immediately, except for 6 minute dwell before energizing compressor circuit. Indicator lights will stop flashing after Display On or Alarm Off pads are pressed.

EEPROM Update in Control Memory

EEPROM is permanent programmable memory device. Once function is changed and stored in EEPROM, function is stored permanently and will not be effected by power loss.

•After keyboard programming changes have been made to refrigerator and freezer temperatures, entry tone, and door audio alarm, status is permanently stored in EEPROM after keyboard is disabled.

Accessing Program Mode

1.Open refrigerator door.

2.Press Display On pad.

3.Press Vacation pad.

4.Press following pads in sequence within

6 seconds: Max Ref, Max Frz, Max Ref, Max Frz.

5.When access is granted, audio annunciator will sound 3 times and control will be in program Mode A.

RS1200001 28 November 1996