Carrier 69NT40-561-019, Operation And Service Manual

Page: 57 / 136

4–31 T-359
Table 4–6 Controller Alarm Indications
CODE # CAUSE COMPONENTS TROUBLESHOOTING CORRECTIVE ACTIONS
AL03
Loss of
Superheat
Control
Superheat has re-
mained below 1.66

C
(3

F) degrees for five
minutes continuously
while compressor run-
ning. Compressor
drawing more than 2.0
amps, compressor
pressure ratio is great-
er than 1.8, and Elec-
tronic Expansion
Valve (EEV) is at 0%
open.
Electronic Expan-
sion Valve (EEV) Check the operation of
the EEV using Cd41. Replace EEV if
defective.
Evaporator Tem-
perature Sen-
sor(s) ETS &
ETS1. Verify accuracy of tem-
perature sensors, refer to
Sensor Checkout Proce-
dure
Section 7.19.1 .
Replace ETS or ETS1
if defective.
Evaporator Fans
Confirm fans
operating properly.
Replace fan(s) if defective,
refer to
EVAPORATOR FAN MO-
TOR ASSEMBLY
Section
7.10 .
AL05
Manual
Defrost
Switch
Failure
Controller has detect-
ed continuous Manual
Defrost Switch activity
for five minutes or
more.
Keypad Power cycle the unit.
Resetting the unit may cor-
rect problem, monitor the
unit.
If the alarm reappears af-
ter 5 minutes replace the
keypad.
AL06
Keypad or
Keypad
Harness Fail
Controller has detect-
ed one of the keypad
keys is continuously
activity.
Keypad or
Harness
Power cycle the unit.
Resetting the unit may cor-
rect problem, monitor the
unit.
If the alarm reappears re-
place the keypad and har-
ness.
AL07
Fresh Air
Vent Open
with
Frozen Set
Point The VPS is reading
greater than 0 CMH
while unit is in frozen
mode.
Vent Position Sen-
sor (VPS)
Manually reposition vent
and confirm using Cd45.
Refer to VENT POSI-
TION SENSOR SER-
VICE Section.
If unable to obtain zero
reading, replace defective
VPS.
AL08
High
Compressor
Pressure Ra-
tio
Controller detects dis-
charge pressure to
suction pressure ratio
is too high.
The controller will at-
tempt to correct the sit-
uation by restarting
the compressor.
Discharge
Pressure
Transducer (DPT)
Confirm accurate DPT
pressure readings, refer
to MANIFOLD GAUGE
SET
Section 7.2 .
Replace DPT if defective.
AL10
CO
2
Sensor
Failure
Alarm 10 is triggered
when the CO
2
sensor
voltage is operating
outside of the 0.9 v to
4.7 v range, or if the
sensor is out of range.
This is a display
alarm and has no
associated failure
action.
Refer to eAutoFresh
manual.
The alarm is triggered off
when voltage is within op-
erating range.