Carrier 25VNA Service Manual page 14

FLASH CODE
OPERATION
(Amber LED)
Event 49
Fault 53
Fault 54
Fault 55
Event 56
Fault 57
Event 58
25VNA EVENT / FAULT (CONT.)
Heat or Cool
Possible Causes
Mode
Contactor dropping out momentar-
ily
Both
Voltage glitches and low line
voltages
Damaged Inverter Drive
Sensor Harness not connected to
ODU control
Broken or loose harness wire
Both
Broken or Damaged Sensor
Hardware damage to ODU control
Sensor Harness not connected to
ODU control
Broken or loose harness wire
Both Suction Thermistor not properly at-
tached or in wrong location
Broken or Damaged Sensor
Hardware damage to ODU control
Sensor Harness not connected to
ODU control
Broken or loose harness wire
Both Coil Thermistor not properly at-
tached or in wrong location
Broken or Damaged Sensor
Hardware damage to ODU control
Coil Thermistor not properly at-
tached or in wrong location
Outdoor Ambient Temperature
Both
sensor improperly installed (sensor
body may be in contact with sheet
metal)
Sensor Harness not connected to
ODU control
Broken or loose harness wire
Both
Electrical short destroyed Trans-
ducer electronics
Heat damage during brazing
Suction Thermistor not properly at-
tached or in wrong location
Both
Broken or loose harness wire
14
ACTION
Verify contactor harness from ODU con-
trol ("CC" harness); check for loose con-
nection, stripped wires, short to ground
or short between wires; confirm good
connection is made at control board and
at contactor
if persistent contact power provider
Change out ODU control before Inverter
Drive; if this does not help then change
out the Inverter drive
Ensure plug is connected to ODU con-
trol
Check harness for continuity; resistance
should measure 10 k at 77 +/ --- 20
Refer to thermistor 10 k thermistor curve.
If bad, replace OAT/OCT thermistor
sensor assembly
Check harness for continuity; resistance
should measure 10 k at 77 +/ --- 20
Refer to thermistor 10 k thermistor curve.
If bad, replace OAT/OCT thermistor
sensor assembly
Replace ODU control
Ensure plug is connected to ODU con-
trol
Check harness for continuity; resistance
should measure 10 k at 77 +/ --- 20
Refer to thermistor 10 k thermistor curve.
If bad, replace OST sensor
Ensure Sensor is properly attached to
the accumulator entry ---tube
Check harness for continuity; resistance
should measure 10 k at 77 +/ --- 20
Refer to thermistor 10 k thermistor curve.
If bad, replace OST sensor
Replace ODU control
Ensure plug is connected to ODU con-
trol
Check harness for continuity; resistance
should measure 10 k at 77 +/ --- 20
Refer to thermistor 10 k thermistor curve.
If bad, replace OAT/OCT thermistor
sensor assembly
Ensure Sensor is properly clipped to the
distributor entry ---tube
Check harness for continuity; resistance
should measure 10 k at 77 +/ --- 20
Refer to thermistor 10 k thermistor curve.
If bad, replace OAT/OCT thermistor
sensor assembly
Replace ODU control
Ensure Sensor is properly clipped to the
distributor entry ---tube
Properly install OAT sensor
Ensure plug is connected to ODU con-
trol
Check harness for stripped wires, shot to
ground or short between wires.
Compare transducer voltage reading to
gauge reading at service valve (see
Transducer Output Function graph);
Check system for electrical shorts and
correct; replace transducer.
Compare transducer reading to gauge
reading at service valve (see transducer
measurement chart); replace transducer
Ensure plug is properly attached to suc-
tion tube
Check harness for continuity; resistance
should measure 10 k at 77 +/ --- 20
Refer to thermistor 10 k thermistor curve.
If bad, replace OST thermistor sensor
assembly
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