Carrier Transicold 69NT40-561-001 Operation And Service Manual page 75

Alarm Code Cause
AL17 Compressor has at-
Compressor tempted to start in both
Pressure Delta directions and fails to
Fault generate sufficient
pressure differential
between SPT and
DPT.
AL18
Discharge pressure is
Discharge over the maximum for
Pressure High 10 minutes within the
last hour.
Table 4–6 Controller Alarm Indications
Components
N/A
Discharge Pres-
sure Transducer
(DPT)
Suction Pressure
Transducer (SPT)
Monitor Unit
Restrictions in the
refrigeration sys-
tem.
Filter Drier
Condenser Fan
Discharge Pres-
sure Transducer
(DPT)
Non-condens-
ables in the refrig-
eration system.
Refrigerant
4–39
Troubleshooting
Controller will attempt
restart every 20 minutes
and deactivate the alarm
if successful.
Confirm accurate DPT
pressure readings, refer
to MANIFOLD GAUGE
Section 7.2.
SET
Confirm accurate SPT
pressure readings, refer
to MANIFOLD GAUGE
SET Section 7.2.
Alarm is display only the
alarm may clear itself
during operation.
Ensure Liquid Line Ser-
vice Valve is fully open.
Check the filter drier, if it
is iced up or very cold it
indicates that the filter
drier needs replacement.
Check Condenser Fan
for proper operation.
Confirm accurate DPT
pressure readings, refer
to MANIFOLD GAUGE
SET Section 7.2.
With the unit off allow
system to stabilize to
ambient temperature.
Check system pressure
against PT Chart for
134a, refer to Table 7–5.
Check refrigerant level.
Corrective Actions
Resume normal
operation.
Replace DPT if defec-
tive.
Replace SPT if defec-
tive.
If alarm remains active
or is repetitive replace
compressor at next
available opportunity.
Open Liquid Line Ser-
vice Valve as needed.
Replace the filter drier if
needed, refer to FILTER
DRIER Service Section
7.13.
Correct as required.
Replace DPT if defec-
tive.
Correct as required, re-
fer to Refrigerant Charge
Section 7.7.1.
Correct as required, re-
fer to Refrigerant Charge
Section 7.7.1.
T-340