TABLE 4
MC5000BC Series Alarm Functions
Manual 2100-746
Page
33 of 55
HVAC Compressor Lockout Alarm
If the LOR input for any configured unit becomes
active, an HVAC Compressor Lockout alarm will be
triggered. This alarm will include a unit identifier (1-6)
tag in the alarm description. If controller is equipped
with optional alarm board, the HVAC Lockout relay
associated with the unit will change stage. The HVAC
Compressor Lockout alarm will clear once the LOR for
the corresponding unit becomes inactive.
HVAC Maintenance Alarm
If the filter input for any configured unit becomes
active, then an HVAC Maintenance alarm will be
triggered. This alarm will include a unit identifier (1-6)
tag in the alarm description. If controller is equipped
with optional alarm board, the HVAC Maintenance relay
associated with the unit will change stage. The HVAC
Maintenance Alarm will clear when Filter input for
corresponding unit becomes inactive.
HVAC Dust Alarm
If the dust input for any configured unit becomes
active, an HVAC Dust alarm will be triggered. This
alarm will include a unit identifier (1-6) tag in the
alarm description. The HVAC Dust alarm will be cleared
once the dust input becomes inactive. If configured
to do so, the Aux. Out terminal will change state for
economizer disable. This alarm will have the ability to
be configured for Output Logic Only via the webpages.
Output Logic only will block the logging of the alarm
into the alarm log and prevent alarm from being listed
in the Active Alarms list.
Control Fail Output
A Control Fail relay is incorporated into controllers
with the optional alarm board. This relay will change
state if the controller loses power (completely), or
communication is lost between the alarm board and
I/O board or I/O board and display. This relay will move
from its normal state upon power up and booting of the
controller and will remain in that configuration until
communication is lost indicating a failed controller.
Temperature Sensor Failure Alarms
In the event that the primary temperature/humidity
sensor fails (open or shorted), an alarm will be
generated. If no optional REM (remote) temperature
sensors are installed, all temperature and humidity
control will be disabled and all units will stop
operating. If equipped with optional REM sensors that
are configured for indoor temperature, temperature
control will continue using the REM sensor for
consideration in control. Additionally, if a REM
temperature sensor is configured and is disconnected
or shorted, an alarm will be generated and the sensor in
question will not be considered for temperature control
logic. This shall provide redundancy for temperature
control in the event of a single temperature sensor
failure for critical applications.
Alarm Condition
Terminals Available
Default and/or Action
1. Low Temperature Alarm
Output avail (1 collective)
40°F Alarm only
2. High Temperature Alarm #1
Output avail (1 collective)
80°F Alarm only
3. High Temperature Alarm #2
Output avail (1 collective)
90°F Alarm and "A" terminal activates on all
unit terminal strips for ventilation
4. Dirty Filter Alarm
Output avail (1 collective)
Alarm only (maintenance alarm)
5. Emergency Off
Output avail (1 collective)
All functions stop
6. Generator Run Alarm
Output avail (1 collective)
Limits units available to run (default is ALL)
7. Ventilation
Output avail (1 collective)
Alarm and "A" terminal activates on all unit
terminal strips for ventilation
8. Unit Lock Out Alarm (1 per unit)
Output avail (1 per unit)
Switch to "next on" (HP or LP only)
9. High Humidity Alarm
No external output
85%RH Close economizer (if configured)
10. Low Humidity Alarm
No external output
25%RH No action available
11. Unit Power Loss Alarm (1 per unit) Output avail (1 per unit)
Alarm and rotation moves to "next on"
12. Theft Alarm
Output avail (1 collective)
Alarm only (all units report to one output)
13. Control Fail Alarm
Output avail (1)
Alarm Only
