Carrier 38GXC - Manual (Page 19)

19
DIAGNOSTIC CHARTS (CONT.)
Is unit running in outdoor
ambient higher than
110 °F?
Beyond operating range
Outdoor coil clean?
Clean coil.
Problem persists?
Problem solved
Check outdoor coil
temperature thermistor .
Chart 4, ok?
Check motor for open
or short. Ok?
Check output on outdoor
board. Ok?
Replace outdoor board
Replace thermistor .
Problem persists
Problem solved
Replace outdoor motor
Yes
No
No
Yes
No No
No
Yes
No
Yes
Yes
Yes
No
Is unit running in outdoor
ambient higher than
110 °F?
Beyond operating range
Outdoor coil clean?
Clean coil.
Problem persists?
Problem solved
Check outdoor coil
temperature thermistor .
Chart 4, ok?
Check motor for open
or short. Ok?
Check output on outdoor
board. Ok?
Replace outdoor board
Replace thermistor .
Problem persists
Problem solved
Replace outdoor motor
Yes
No
No
Yes
No No
No
Yes
No
Yes
Yes
Yes
No
A09364
Fig. 32 – High Condensing Temperature
Is unit running in outdoor
ambient higher than
110 °F?
Beyond operating range
Outdoor coil clean?
Clean coil.
Problem persists?
Problem solved
Check connections from
OD board. Loose, corroded,
or high resistance?
Check output on
outdoor board. Ok?
Connect low side gauge at
suction service valve.
Measure discharge temp.*
Check amp draw to
compressor? Values within
range?
Replace outdoor board
Replace compressor
Clean/repair connection
Problem persists?
Problem solved
Replace outdoor board
High head, high suction? High head, low suction?
Unit is overcharged.
Reclaim charge and weigh
in correct charge.
Yes
Yes
Yes
Yes
Yes
Yes
No
No
No
No No
No
No
Yes
Yes
No
No
Yes
Yes
Restriction in refrigeration
circuit.
Yes
Outdoor motor ok?
No
Replace motor
*Measure discharge temperature at the sensor on the discharge
tube. See Appendix A5
Is unit running in outdoor
ambient higher than
110 °F?
Beyond operating range
Outdoor coil clean?
Clean coil.
Problem persists?
Problem solved
Check connections from
OD board. Loose, corroded,
or high resistance?
Check output on
outdoor board. Ok?
Connect low side gauge at
suction service valve.
Measure discharge temp.*
Check amp draw to
compressor? Values within
range?
Replace outdoor board
Replace compressor
Clean/repair connection
Problem persists?
Problem solved
Replace outdoor board
High head, high suction? High head, low suction?
Unit is overcharged.
Reclaim charge and weigh
in correct charge.
Yes
Yes
Yes
Yes
Yes
Yes
No
No
No
No No
No
No
Yes
Yes
No
No
Yes
Yes
Restriction in refrigeration
circuit.
Yes
Outdoor motor ok?
No
Replace motor
*Measure discharge temperature at the sensor on the discharge
tube. See Appendix A5
A09365
Fig. 33 – Compressor Overcurrent Protection
38/
40GX
C
(Q
)