Ameristar M4AC6 - Page 19

88-M4PW003-1B-EN 19
Is contactor
engergized?
(contacts closed)
Compressor fails to start
Contactor check
YES
YES
YES
YES
NO
NO
NO
NO
NO
If applicable, is TDR
input voltage
present
Go To: Compressor won’t run
Check for 24 volts AC
across contactor coil
Is voltage
present at
contactor coil?
Replace contactor
Check control
transformer and
control fuse
Is the control
transformer
and fuse good?
Jumper R to Y low
voltage terminals
at thermostat sub
base.
Does the
contactor
energize?
Replace the room
thermostat
Repair or replace
transformer or fuse.
Investigate cause for
failure (possible short in
field wiring)
Repair or replace
connecting wiring
NO
Check ID Low
voltage
transformer
YES
Wait 3 minutes and
check contactor
coil again
L2 L1
T2 T1
IN
OUT
L2 L1
T2 T1
Single Pole Contactor (MS)* Double Pole Contactor (MS)*
Contactor Coil
24 VAC
HIGH
VOLT-
IN
OUT
HIGH
VOLT-
TROUBLESHOOTING