Specifications

39
TROUBLESHOOTING
Complete Unit Stoppage and Restart —
Possi-
ble causes for unit stoppage and reset methods are shown be-
low and in Table 31. Refer to Fig. 3-7 for component arrange-
ment and control wiring diagrams.
GENERAL POWER FAILURE — After power is restored,
restart is automatic through normal MBB start-up.
UNIT ENABLE-OFF-REMOTE CONTACT SWITCH IS
OFF — When the switch is OFF, the unit will stop immediate-
ly. Place the switch in the ENABLE position for local switch
control or in the REMOTE CONTACT position for control
through remote contact closure.
CHILLED FLUID PROOF-OF-FLOW SWITCH OPEN —
After the problem causing the loss of flow has been corrected,
reset is manual by resetting the alarm with the scrolling
marquee.
OPEN 24-V CONTROL CIRCUIT BREAKER(S) — De-
termine the cause of the failure and correct. Reset circuit break-
er(s). Restart is automatic after MBB start-up cycle is com-
plete.
COOLING LOAD SATISFIED — Unit shuts down when
cooling load has been satisfied. Unit restarts when required to
satisfy leaving fluid temperature set point.
THERMISTOR FAILURE — If a thermistor fails in either an
open or shorted condition, the unit will be shut down. Replace
EWT, or LWT as required. Unit restarts automatically, but must
be reset manually by resetting the alarm with the scrolling
marquee.
LOW SATURATED SUCTION — Several conditions can
lead to low saturated suction alarms and the chiller controls
have several override modes built in which will attempt to keep
the chiller from shutting down. Low fluid flow, low refrigerant
charge and plugged filter driers are the main causes for this
condition. To avoid permanent damage and potential freezing
of the system, do NOT repeatedly reset these alert and/or alarm
conditions without identifying and correcting the cause(s).
COMPRESSOR SAFETIES — The 30MP units with Com-
fortLink controls include a compressor protection board that
protects the operation of each of the compressors. Each board
senses the presence or absence of current to each compressor.
If there is a command for a compressor to run and there is
no current, then one of the following safeties or conditions
have turned the compressor off:
Compressor Overcurrent
— All compressors have internal
line breaks or a motor protection device located in the com-
pressor electrical box.
Compressor Short Circuit
— There will not be current if the
compressor circuit breaker that provides short circuit protection
has tripped.
Compressor Motor Over Temperature
— The internal line-
break or over temperature switch has opened.
High-Pressure Switch Trip
— The high-pressure switch has
opened. See Table 24 for the factory settings for the fixed high-
pressure switch.
ASTP Protection Trip
— All non-digital Copeland compres-
sors are equipped with an advanced scroll temperature
protection (ASTP). A label located above the terminal box
identifies models that contain this technology. See Fig. 25.
Advanced scroll temperature protection is a form of internal
discharge temperature protection that unloads the scroll com-
pressor when the internal temperature reaches approximately
300 F (149 C). At this temperature, an internal bi-metal disk
valve opens and causes the scroll elements to separate, which
stops compression. Suction and discharge pressures balance
while the motor continues to run. The longer the compressor
runs unloaded, the longer it must cool before the bi-metal disk
resets. See Fig. 26 for approximate reset times.
To manually reset ASTP, the compressor should be
stopped and allowed to cool. If the compressor is not stopped,
the motor will run until the motor protector trips, which occurs
up to 90 minutes later. Advanced scroll temperature protection
will reset automatically before the motor protector resets,
which may take up to 2 hours.
High Discharge Gas Temperature Protection
— Units
equipped with optional digital compressors have an additional
thermistor located on the discharge line, If discharge tempera-
ture exceeds 265 F (129.4 C), the digital compressor will be
shut off.
Alarms will also occur if the current sensor board malfunc-
tions or is not properly connected to its assigned digital input. If
the compressor is commanded OFF and the current sensor
reads ON, an alert is generated. This will indicate that a com-
pressor contactor has failed closed. In this case, a special mode,
Compressor Stuck on Control, will be enabled and all other
compressors will be turned off. An alarm will then be enabled
to indicate that service is required. Outdoor fans will continue
to operate. The condenser output is turned on immediately.
Alarms and Alerts — These are warnings of abnormal
or fault conditions, and may cause either one circuit or the
whole unit to shut down. They are assigned code numbers as
described in Table 32.
Automatic alarms will reset without operator intervention if
the condition corrects itself. The following method must be
used to reset manual alarms:
Before resetting any alarm, first determine the cause of the
alarm and correct it. Enter the Alarms mode indicated by the
LED on the side of the scrolling marquee display. Press
and until the sub-menu item RCRN “RESET
ALL CURRENT ALARMS” is displayed. Press .
The control will prompt the user for a password, by displaying
PASS and WORD. Press to display the default pass-
word, 1111. Press for each character. If the password
has been changed, use the arrow keys to change each individu-
al character. Toggle the display to “YES” and press .
The alarms will be reset.
CAUTION
If unit stoppage occurs more than once as a result of any of
the safety devices listed, determine and correct cause
before attempting another restart.
Fig. 25 — Advanced Scroll Temperature
Protection Label
ENTER
ENTER
ENTER
ENTER
ENTER