GE AS0CD09 Series, Technical Service Manual, Page: 15 / 72

13
6. Defrost Control
•
Defrost operation is controlled by timer and sensing temperature of outdoor pipe.
•
The first defrost starts only when the outdoor pipe temperature falls below 21
0
F after 60 minutes has passed from
starting of heating operation and more than 10 minutes operation of compressor.
•
Defrost ends after 12 minutes has passed from starting of defrost operation or when the outdoor pipe temperature
rises over 54
0
F even if before 12 minutes.
•
The second defrost starts only when the outdoor pipe temperature falls below 21
0
F after 60 minutes has passed from
ending of the first defrost and more than 10 minutes operation of compressor.
•Protection of the indoor heat exchanger from frosting
•
Compressor and outdoor fan stop when indoor pipe temperature is below 32
0
F and restart when the pipe temperature
is above 45 0 F.
OUTDOOR
PIPE TEMP.
More than 60 minutes of
heating operation Within
12 minutes
More than 60 minutes of
heating operation
Defrost
More than 10 minutes
running of compressor
More than 10 minutes
running of compressor
Defrost
HOT-
START
OFF
OFF
OFF
OFF
ON
ON
ON
ON
ON
ON
ON
ON
54 F
(DEFROST OFF)
21 F
(DEFROST ON)
INDOOR FAN SPEED
COMPRESSOR
4-WAY VALVE
0
0