York SSS 14L-B, Operation Manual

Page: 26 / 40

JOHNSON CONTROLS
26
FORM 160.00-O2
ISSUE DATE: 04/30/2019
SECTION 5 – CYCLING SHUTDOWNS
Possible Problems
• Verify the communication cable between the
OptiView Control Center and the Logic/Trigger
Board.
• If CR6 is blinking, but CR7 is not blinking, the
Logic/Trigger Board has failed. If both CR6 and
CR7 are blinking every two seconds continue to
the next step
• If problem is still not detected, then perform the
communication loop back test (ASSOCIATED
LITERATURE listed on page 3 for OptiView
Control Center Service).
INVALID CURRENT SCALE
To protect the motor and starter from high current con-
ditions, and the chiller from Power Fault conditions,
the current transformers must be properly connected
to the Logic/Trigger Board. The current transformers
are connected to the Logic/Trigger Board via the P1/
J1 connector. This connection also determines starter
HP size, and allows the use of only one Logic/Trigger
Board. If P1 is not connected to J1, the three inputs
to determine the starter size will be pulled high and
a Cycling shutdown will occur. The presence of the
P1/J1 connector is verified when power is applied to
the starter. During the period that the connector is not
connected to J1, the three phase currents and the KW
values will be displayed as zero on the display of the
OptiView Control Center.
Generally, this shutdown will occur during the start-up
of the chiller.
The shutdown message displayed will be
“LCSSS -
INVALID CURRENT SCALE SELECTION” .
Possible Problems
• Verify that the J1 connector is installed on the
Logic/Trigger Board.
• Verify the wiring of the J1 connector.
LOGIC BOARD POWER SUPPLY
Whenever power is applied to the LCSSS this shut-
down is indicated.
The shutdown message displayed will be
“LCSSS -
Logic Board Power Supply”
.
Possible Problems
Check for possible input power problems.
LOGIC BOARD PROCESSOR
A watchdog type of system is used to determine if
the main system microprocessor and the DSP are still
communicating. Normally, the main system micro-
processor and the DSP communicate every 3 mSec.
A watchdog counter is set-up in the main system mi-
croprocessor to a count of 80. If after 80 attempts to
communicate between the main system microproces-
sor and the DSP, and the DSP still does not respond, a
Cycling shutdown will occur. At the same point in time
the DSP will be rebooted. The watchdog timer will
only reset if communications have been established.
The shutdown message displayed will be
“LCSSS -
LOGIC BOARD PROCESSOR”
.
Possible Problems
If the problem continues replace the Logic/Trigger
Board.
LOW PHASE TEMPERATURE
The value of each thermistor mounted on the SCR as-
semblies is constantly compared to a shutdown thresh-
old value of 37°F in the main system microprocessor.
If any one of the three thermistors has a value that cor-
responds to 37°F or lower, a Cycling shutdown will
occur. The thermistors are connected to the Logic/
Trigger Board at plugs P2, P3, P4.
The shutdown message displayed will be
“LCSSS
- LOW PHASE X TEMPERATURE SENSOR” ,
where X is either A, B or C corresponding to SCR
phase assemblies A, B or C respectively.
Possible Problems
• This problem is normally associated with a open
thermistor.
• Verify that P2, P3, and P4 are connected to the
Logic/Trigger Board.
• Verify the interconnection between the thermistor
and the P2, P3, and P4 connectors.
LOW SUPPLY LINE VOLTAGE
The Logic/Trigger Board monitors the three phases of
input voltage via the negative SCR cathode connec-
tion. The DSP determines the phase to phase RMS
voltage and sends this information to the main sys-
tem microprocessor. The main system microprocessor
will compare these voltages to shutdown thresholds in
Table 4. If the input voltage falls below the shutdown
threshold for 20 continuous seconds, then a Cycling