173
Using the rate of change of the suction from the example,
five (5) seconds after t=0, the suction pressure should be 193.8
psig (1336 kPa), if the compressor did not start. Subtracting
the 1.25 psig (8.62 kPa) from extrapolated suction pressure,
192.55 psig (1328 kPa) determines the upper limit that if the
suction pressure is above this level the unit will fault on reverse
rotation. This point is denoted by a black dot in Fig. 189 and
190. In the example, the suction pressure is lower than the up-
per limit, and therefore is allowed to continue operation.
Action To Be Taken:
The unit shuts down immediately.
Reset Method:
Manual.
Possible Causes:
If this condition is encountered, check the
following items:
• Check the wiring of the incoming power for proper phas-
ing. This alarm may be disabled once the reverse rota-
tion check has been verified by setting Reverse Rotation
Enable
Configuration
o
SERV
o
REV.R=
DSBL
.
• Check Control Type (
Configuration
o
OPT2
o
C.TYP
)
setting. If the A1 compressor is a digital compressor and
is enabled (
Configuration
o
UNIT
o
A1.TY=
YES
),
C.TYP
must be selected for a digital compressor compat-
ible control option,
1
(VAV),
3
(TSTAT MULTI),
5
(SPT
MULTI),
7
(PCT CAP), or
9
(VAV SETPOINT).
A150 — Unit is in Emergency Stop
Criteria for Trip:
This alarm is indicated when a CCN Emer-
gency Stop command is received. If the CCN point name
EMSTOP in the CCN Status Table is set to “Emstop,” the unit
will shut down and generate this alarm.
Action To Be Taken
: The unit is shut down or not allowed to
start.
Reset Method:
Automatic, once the Emergency Stop command
is revoked. This alarm will clear when the EMSTOP point
value is returned to “Enable.”
Possible Causes:
If this condition is encountered, check the
value of the CCN point, EMSTOP. If it is “Emstop,” change it
to “Enable.”
A151 — Illegal Configuration Alarm
Criteria for Trip:
This alarm is indicated when an illegal con-
figuration has been entered. There are several different config-
uration alarms. When expanding the alarm, the control will
indicate which configuration is incorrect. For example, if the
wrong size is configured, the A151 expansion will indicate
“ILLEGAL CONFIG - INVALID UNIT SIZE.”
Action To Be Taken:
The unit is not allowed to start.
Reset Method:
Automatic, once the illegal configuration is cor-
rected.
Possible Causes:
If this condition is encountered, check the
items shown in Table 80 based on the illegal configuration.
Table 80 — Illegal Configurations (Alarm A151)
ILLEGAL CONFIGURATION
POSSIBLE CAUSES
AUX BOARD INCORRECT REVISION
Check to see if the AUX Board is an older revision not compatible with the current software.
Check the red LED on the AUX Board to be sure that it is blinking in unison with the other
boards in the unit. If it is not, it is not communicating:
- Check the LEN Communication wiring for continuity to the Main Base Board.
- Check the AUX Board DIP Switch settings for the address.
For 208 volt systems, check the control transformer to be sure that it is tapped correctly.
Consider cycling power to the AUX Board.
AUX BOARD SOFTWARE REV
MUST BE 3 OR HIGHER
Check to see if the AUX Board is an older revision not compatible with the current software.
The AUX Board software revision can be found in the vendor part number, CEPL130567-03.
The -03 indicates Revision 03.
AUX BOARD SHOULD BE AUX1, NOT AUX2
Check the part number of the AUX Board. It should have the Carrier Part Number
32GB500442EE (UTEC Part Number CEPL130567-03). This board is required for the digital
compressor output as well as the Motormaster drive signal. An AUX2 Board, Carrier Part
Number 332GB500432EE (UTEC Part Number CEPL130568-02) does not have the capability
to supply these outputs.
CONTROL TYPE SET TO INVALID TYPE FOR
SPLIT
Check
Configuration
o
OPT2
o
C.TYP
for a valid control type.
DUAL THERMOSTAT TYPE ON
SINGLE CKT UNIT
Check to see if
Configuration
o
OPT2
o
C.TYP =
8
(DUAL TSTAT) control type is configured
for a single circuit machine,
Configuration
o
UNIT
o
NCKT =
1
(Single Circuit)
DUAL THERMOSTAT AND
SWITCH DEMAND LIMIT
Check to see if
Configuration
o
OPT2
o
C.TYP =
8
(DUAL TSTAT) control type is configured
with switch control demand limit enabled,
Configuration
o
RSET
o
DMDC =
1
(Switch).
INVALID UNIT SIZE HAS BEEN ENTERED
Check to be sure that a valid unit size
Configuration
o
UNIT
o
SIZE
has been entered.
UNIT CONFIGURATION SET TO
INVALID TYPE
Digital compressor,
Configuration
o
UNIT
o
A1.TY=
YES
, and hot gas
Configuration
o
OPT1
o
MLV=
YES
are both enabled. Only one can be enabled.