Service Guide

24
9) Defrost–The defrost icon turns on and "dEF" is displayed during defrost. There is a
5-min. minimum defrost time and a 1-hr.maximum defrost time.
1a) Time-Initiated: 4-hr. cumulative Comp run time defrost timer starts. Once 4-hr.
cumulative Comp run time defrost timer terminates (Comp energized more than
4hrs.).
1b) Manually-Initiated: To initiate a manual defrost, press the manual defrost button on
display.
Defrosticon turns on and "dEF"is displayed. DH energizes. If on, Comp and EvapFM
icons turn off. Comp and EvapFM icons turn off, Comp, ConFM, and EvapFM
de-energize.
2a) Time-Initiated Defrost-Termination:
(1) DTh warms to 59°F (15°C). Defrost icon and "dEF" continue. DHde-energizes.
3-min. Comp delay timer starts, 7-min. EvapFM delay timer starts, and 18-min.
temperature display delay timer starts.
(2) 3-min. Comp delay timer terminates. "dEF" continues. Defrost icon turns off and
Comp icon turns on and Comp and ConFM energize.
(3) 4 min. later, 7-min. EvapFM delay timer terminates. Comp, ConFM, and "dEF"
continue. EvapFM icon turns on and EvapFM energizes. Note that the 7-min.
EvapFM delay time is a maximum; if the defrost thermistor cools to 25°F (-3.9°C)
before the 7-min. EvapFM delay timer terminates, EvapFM icon turns on and
EvapFM energizes.
(4) 11-min. later, 18-min. temperature display delay timer terminates. "dEF" is
replaced by cabinet temperature.
2b) Manually-Initiated Defrost-Termination:
(1) DTh warms to 59°F (15°C). Defrost icon and "dEF" continue. DHde-energizes.
3-min. Comp, ConFM, and EvapFM delay timer starts, and 15-min. temperature
display delay timer starts.
(2) 3-min. Comp, ConFM, and EvapFM delay timer terminates. "dEF," Defrost icon
turns off, Comp and EvapFM icons turn on, and Comp, ConFM, and EvapFM
energize.
(3) 12-min. later, 15 min. temperature display timer terminates. "dEF" is replaced by
cabinet temperature.
Defrost Diagnosis:
1) Time-Initiation or Manual Initiation: 4-hr. Comp cumulative run time defrost timer
terminates or CM defrost button pressed.
(1) CM Diagnosis: Conrm defrost icon turns on, "dEF" is displayed, and Comp and
EvapFM icons turn off. If not, replaceCM. Next, check that CM C1 (R or V) and
CM F5 (Y or W/BU) do not have 115VAC to neutral (W). If 115VAC is present,
replace CM. Check for 115VAC at CM H4 (O) to neutral (W). If 115VAC is not
present, replace CM.
(2) DH Diagnosis: Conrm DH energizes (amp draw). If not, check for 115VAC at
DT (BK) to neutral (W). If 115VAC is not present, check DT continuity. If open, let
cool and reset. If DT does not close, replace DT. If DT is closed, check DH amp
draw and continuity.