Defrost Control - GE AS0CD09 Series Technical Service Manual

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