Carrier 25VNA - Page 24

24
Check system
refrigerant
charge
& air flow
WARNING!
Disconnect &
lock-out power
and recover
system charge
Measure
resistance
between each of
the three fusite
pins and ground
(See Fig. 20 & 21)
Check for
restricted
refrigerant flow
and/or high
superheat
Remove the
molded plug from
the thermistor
fusite on the
compressor
(See Fig. 19)
The molded plug
harness is
grounded-replace
it
Put system back
into operation
Yes
Install new
molded plug
assembly and
route wires
carefully
Is there continuity
between any of the
pins and ground
?
A
B
Reset motor
temp fault at
system controller
A
No
Change the
compressor
No
Yes
Confirm phasing
is correct to
compressor
(yellow, black,
red wires on
drive output.
(See Fig. 23)
Confirm
operation inside
compressor/unit
temperature &
speed range
Check and verify
correct drive part
number
System still
faulting on
motor temp?
Normal
operation --
monitor
Troubleshoot the
thermistor circuit
C
Is input current to
drive less than unit
full load amp rating?
Replace
compressor
Yes
No
WARNING !
Disconnect &
lock-out power,
allow 2 minutes
for drive to
discharge
A11555
Fig. 15 – Motor Temp Fault Troubleshooting -- Part 2