A.O. Smith CAHP-MC-38 Installation, Operation And Maintenance Instructions page 41

Operation
Move to "
MANUAL DEFROST
pressing the Up/Down button,
then press SELECT button to
start this process.
The " " interface
Manula Defrost
will be displayed subsequently.
Press YES button to excute the
defrosting process or press the
NO button to cancel the
process.
The defrosting command will
be sent to all the heat pump if
YES button is pressed in the
previous step and the UIM will
display "COMMAND
SENDING ... "
Press BACK button to return to
the previouse UIM interface.
Note: This operation can't be selected when heat pump unit is ON.
Manual Defrost Operation Process
" by
M A I N T E N A N C E S E T T I N G
A U X H E A T E R D I F F
A U X H E A T E R
A U X H E A T E R T Y P E
M A N U A L D E F R O S T
H P T E M P A D J
S E L E C T
M A N U A L D E F R O S T
Y E S
M A N U A L D E F R O S T
M A N U A L D E F R O S T
M A I N T E N A N C E S E T T I N G
A U X H E A T E R D I F F
A U X H E A T E R
A U X H E A T E R T Y P E
M A N U A L D E F R O S T
H P T E M P A D J
S E L E C T
Display
2 ℃
W I T H
T A N K L E S S
0 ℃
B A C K H E L P
A L L T H E U N I T S R U N
D E F R O S T I N G ?
N O
A L L T H E U N I T S R U N
D E F R O S T I N G ?
C O M M A N D S E N D I N G ...
A L L T H E U N I T S R U N
D E F R O S T I N G ?
S U C C E E D E D ！
B A C K
2 ℃
W I T H
T A N K L E S S
0 ℃
B A C K H E L P
Description
The manual defrosting is
successful if the UIM
display "SUCCEEDED!"
and all the heat pump
should enter the
defrosting cycle.
If the UIM display
"FAILED!", it indicates the
manual defrosting is
unsuccessful, please
check the communication
between the central
controller and the heat
pump units.