Carrier 42HWG009 Technical Data & Service Manual page 24

2) Preceding condition is
a) The first step is "the accumulated compressor on time is greater than 30
minutes."
b) Second step is the one of below two
-The first condition ; If Real-Delta>Defrost-Delta for 60 continuous seconds and
the following conditions are all true then defrost initiates.
)The outdoor coil temperature<-2°C
)The compressor has been on continuously for 15 minutes.
OR
-The second condition ; If the outdoor coil temperature is less than -20°C and
the following conditions are all true then defrost initiates.
)The outdoor fan has been on continuously for 60 seconds.
)The compressor has been on continuously for 3 minutes.
• Defrost mode
The normal system operations are stopped and the system operates as follows.
a) The indoor fan, outdoor fan will be de-energized.
b) The compressor and R.V.S. will be energized.
• Defrost termination
The defrost cycle will terminate in one of the following cases.
a) The outdoor coil temperature is greater than or equal to +25°C.
b) 10 minutes after the start of defrost cycle.
• Auto refresh
During normal heating operation, if the unit becomes OFF mode condition, then
defrost mode will be performed at the OFF mode state of louver and display when
the second step of preceding conditions is satisfied regardless of first step.
Self-Diagnostic Function
The control will contain diagnostic test to verify the integrity of the system.
Once a malfunction is detected, the diagnostic control section will force the system mode
to OFF for 3 minutes. After the OFF delay, system mode is released and allowed to return
to its normal state. The system will be allowed to restart on its own. The diagnostic control
section will allow the system to fail 5 consecutive times before shutting down the system.
The lamp is scanned every half second and the error codes are displayed by the
flashing frequency of
minutes off and after the 5th retry failure) as follows.
lamp. The error codes are displayed during SHUT-OFF (3
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