Carrier 25VNA - Page 22

22
Check system
refrigerant
charge & air flow
Measure
discharge temp
(within 6" of
compressor )
WARNING!
Disconnect &
lock-out power
and recover
system charge
Measure
resistance
between each of
the three fusite
pins and ground
(See Fig. 22)
Discharge
temp less
than 250 °F?
Normal
operation -
monitor
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?
If scroll temp
fault still exists,
change
compressor
A
B
Reset scroll temp
fault at system
controller &
remove power to
drive to reboot
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
Adjust expansion
device to 10-20°F
superheat
A11553
Fig. 13 – Scroll Temp Troubleshooting -- Part 2