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Code
TITLE
No.
Manual Defrost
AL05
Switch Failure
Keypad or Harness
AL06
Failure
Fresh Air Vent Open
with Frozen Set
AL07
Point
High Compressor
AL08
Pressure Ratio
Evaporator Motor 1
AL11
IP Trip
Evaporator Motor 2
AL12
IP Trip
Phase Sequence
AL14
Failure - Electronic
AL15 Loss of Cooling
Compressor Current
AL16
High
Phase Sequence
AL17
Failure - Pressure
Discharge Pressure
AL18
High
Discharge Tempera-
AL19
ture High
Control Circuit Fuse
AL20
Open (24 VAC)
T-334
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Table 3- -6 Controller Alarm Indications (Sheet 1 of 4)
Alarm 05 is triggered if the controller detects continuous Manual Defrost Switch
action for 5 minutes or more. The alarm will only trigger off when the unit is pow-
er cycled.
Alarm 06 is triggered if the controller detects continuous keypad button activity
for 5 minutes or more. The alarm will only trigger off when the unit is power
cycled.
Alarm 07 is triggered if the VPS is reading greater than 0 CMH based on the
function code display value and a frozen set point is active.
If AL 50 is active, AL 07 will not be generated.
The alarm will go inactive if the VPS reading transitions to 0 CMH, the set point
transitions to the perishable range, or an AL50 is active.
Alarm 08 is triggered when the controller detects discharge pressure:suction
pressure ratio is too high. This is a display alarm and has no associated failure
action.
Alarm 11 is applicable to units with Single Evaporator Fan Capability (CnF32 set
to 1EFO) only. The alarm is triggered if the evaporator fan motor #1 internal pro-
tector opens. If the alarm is active, probe check is deactivated.
Alarm 12 is applicable to units with Single Evaporator Fan Capability (CnF32 set
to 1EFO) only. The alarm is triggered if the evaporator fan motor #2 internal pro-
tector opens. If the alarm is active, probe check is deactivated.
Alarm 14 is triggered if the electronic phase detection system is unable to deter-
mine the correct phase relationship. AL 14 is also triggered if electronic phase
sequence detection was successful and conclusive, but unit is miswired. The
miswiring causes increased suction pressure and decreased discharge pressure
when the compressor is running; these conditions are present only when the
compressor is energized in the direction opposite of that indicated by electronic
phase sequence detection. If the system is unable to determine the proper rela-
tionship, alarm 14 will remain active. Additional information on phase detection
may be displayed at Function Code Cd41. If the right most digit of Code Cd41 is
3 or 4, this indicates incorrect motor or sensor wiring. If the right most digit is 5,
this indicates a failed current sensor assembly.
Alarm 15 is activated when SMV is greater than 15%, unit is in economized or
standard operating modes and Return - Supply Temperature Difference is less
than 0.5C after 4 minutes of compressor run time. The alarm triggers failure ac-
tion C (evaporator fan only) or D (all machinery off) if in perishable mode and fail-
ure action D (all machinery off) if a frozen set point has been selected. The alarm
remains active until the unit is power cycled.
Alarm 16 is triggered if compressor current draw is 15% over calculated maxi-
mum for 10 minutes out of the last hour. The alarm is display only and will trigger
off when the compressor operates for one hour without over current.
Alarm 17 is triggered if a compressor start in both directions fails to generate suf-
ficient pressure differential. The controller will attempt restart every twenty min-
utes and deactivate the alarm if successful. This alarm triggers failure action C
(evaporator fan only) or D (all machinery off) of Function Code Cd29 if the unit
has a perishable set point. Failure action D (all machinery off) is triggered if the
unit has a frozen set point
Alarm 18 is triggered if discharge pressure is 10% over calculated maximum for
10 minutes within the last hour. The alarm is display only and will trigger off when
the compressor operates for one hour without overpressure.
Alarm 19 is triggered if discharge temperature exceeds 135C (275F) for
10 minutes within the last hour. The alarm is display only and will trigger off when
the compressor operates for one hour without over temperature.
Alarm 20 is triggered by control power fuse (F3A, F3B) opening and will cause
the software shutdown of all control units. This alarm will remain active until the
fuse is replaced.
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