Carrier 38GXC - Manual (Page 18)

18
DIAGNOSTIC CHARTS (CONT.)
Reset main power and
restart system using remote.
Problem persists?
No further action is
required
No
Yes
Measure Volts DC on
outdoor TB between S & N.
Ok? **
Yes
Check the wires (type) and
connections between
Indoor and outdoor units
*
No
Fix connection or
replace wiring
No
Yes
Replace outdoor board.
* Thermostat wires cannot be used. Wires should be connected
communication error.
** There is 3 minutes to make the measurement before the diagnostic light comes back on.
Measure Volts DC on
indoor TB between S & N.
Ok? **
No
Replace indoor board.
Recheck wiring and
connections
Notes:
Before measuring the Volts DC on outdoor TB,
disconnect the field wire on terminal S.
Before measuring the Volts DC on Indoor TB,
disconnect the field wire on terminal S.
Have the red probe of the meter on terminal S
and the black probe on terminal N. Reconnect
wiring when measurements are complete.
Reset circuit breaker. Is
problem fixed?
Problem fixed
Yes
Yes
No
Reset main power and
restart system using remote.
Problem persists?
No further action is
required
No
Yes
Measure Volts DC on
outdoor TB between S & N.
Ok? **
Yes
Check the wires (type) and
connections between
Indoor and outdoor units
*
No
Fix connection or
replace wiring
No
Yes
Replace outdoor board.
per connection diagrams. Failure to do that will result in a
Polarity needs to be maintained between indoor and outdoor units
Measure Volts DC on
indoor TB between S & N.
Ok? **
No
Replace indoor board.
Recheck wiring and
connections
Notes:
Before measuring the Volts DC on outdoor TB,
disconnect the field wire on terminal S.
Before measuring the Volts DC on Indoor TB,
disconnect the field wire on terminal S.
Have the red probe of the meter on terminal S
and the black probe on terminal N. Reconnect
wiring when measurements are complete.
Reset circuit breaker. Is
problem fixed?
Problem fixed
Yes
Yes
No
A09362
Fig. 30 – Communication Error
Reset main power and
restart system using remote.
Problem persists?
Check sensor resistance.
Appendix A4
No further action is
required
No
Yes
Check input and output
on indoor or outdoor board.
Yes
Check sensor connector
at ID or OD board
Connection good?
No
Fix connection
Yes
No
Replace board
No
Replace sensor
Double check connection,
for corrosion or high
resistance.
Yes
Reset main power and
restart system using remote.
Problem persists?
Check sensor resistance.
Appendix A4
No further action is
required
No
Yes
Check input and output
on indoor or outdoor board.
Yes
Check sensor connector
at ID or OD board
Connection good?
No
Fix connection
Yes
No
Replace board
No
Replace sensor
Double check connection,
for corrosion or high
resistance.
Yes
A09363
Fig. 31 – Temperature Sensor
38/
40GX
C
(Q
)