Trane 4TTA3030AD000A - Troubleshooting Guide; Compressor Fails to Start; Compressor Wont Run

4 4TTA3AD-SF-1A
TROUBLESHOOTING
L2 L1
T2 T1
IN
OUT
L2 L1
T2 T1
Single Pole Contactor (MS)* Double Pole Contactor (MS)*
Contactor Coil
24 VAC
HIGH
VOLTAGE
IN
OUT
HIGH
VOLTAGE
*Refer to Wiring Diagram to determine if a single pole or double pole contactor is used.
Check for open IOL
(Internal Overload)
Check resistance of
C to S and C to R
Does the
resistance check
show an open
circuit from C to S
or C to R?
YES
Allow compressor
time to cool and
re-test
NO
Check for open
windings.
YES
Does a resistance check
show an open circuit
between R and S?
Replace the
compressor
NO
Check for locked
rotor
Is voltage present
at C to S and C
to R with locked
rotor amps on C?
YES
Check Start-
Capacitor and
Relay (if present)
and Run Capacitor
Do the start
components and
run capacitor
check good?
YES
Replace the
compressor
NO
Replace start
components and/
or run capacitor
NO
Check wiring to
compressor
C, S and R
Check for high
voltage to contactor
Is high voltage present
at T1 and T2 ?
YES
NO
Check power
supply from
disconnect and/or
breaker panel.
Compressor won’t run
Contactor is closed
Is contactor
energized?
(contacts closed)
Is voltage
present at
contactor coil?
Replace contactor
YES
NO NO
Check for 24 volts AC
across contactor coil
Check control
transformer and
control fuse
Is the control
transformer
and fuse good?
NO
YES
Repair or replace
transformer or fuse.
Investigate cause for
failure (possible short in
field wiring)
Jumper R to Y low
voltage terminals
at thermostat sub
base.
Does the
contactor
energize?
NO
Repair or replace
connecting wiring
YES
Go To: Compressor won’t run
Replace the room
thermostat
YES
Compressor fails to start
Contactor check