Manual 2100-620A - Bard D36A2P/BLD.10304 Installation And Service Instructions Manual

1. If the switch opens, the board ignores the
switch for 2 minutes (OAT above 50°F) or 3
minutes (OAT below 50°F).
2. If the switch is still open after the delay, the
board will stop compressor and outdoor fan
function (soft lockout) for 2 minutes.
3. If after 2 minutes, the low pressure switch is
still open, or opens again immediately aftward,
the board will delay for 2 minutes again (soft
lockout).
4. On the 3rd attempt, the board will lock out
the compressor and outdoor fan until manually
reset.
• High Temperature 2 Alarm – Should the shelter
controller see 90°F, both free-cooling dampers will
open (regardless of outdoor temperature) to cool
the building.
• Smoke Alarm – Should the smoke detector send
an alarm signal to the controller, all blower,
compressor and ventilations functions cease.
LC SERIES PLC CONTROLLER
SEQUENCE OF OPERATION
Overview
The LC Series PLC controller is designed to operate
two (2) Bard D-Series wall-mount units in a lead/lag
fashion, while offering extensive alarming capabilities
as well as remote communication. Inside the LC-1000
cabinet, there is a control board, a 48VDC to 24VDC
converter/power source, six (6) isolation relays (to
protect against errant voltages) and a terminal block.
The LC-1500 series has an additional factory-wired
66 connection block for ease in connecting external
alarms. The duty of the PLC controller is to monitor
temperature and alarm conditions within the shelter
and to send cooling or heating orders to one, or both,
wall-mount units. The controller also monitors the units
and sends alarms.
Inputs/Outputs
The LC controller will make decisions and trigger
alarms by the use of inputs and outputs to various
field-installed connections to the terminal block. Please
refer to the Installation section of this manual for
further information on field-wire connections.
Power Inputs:
• -48VDC positive-ground power to terminals 1 (+)
and 2 (-). This feeds the 48VDC to 24VDC power
converter, which then powers the board and Bard-
supplied hydrogen and smoke detectors. NOTE:
Output must be minimum 22.8 VDC to allow
proper PLC board operation.

Manual 2100-620A

Page 44 of 107
• Hydrogen Alarm (if installed) – Should the
hydrogen detector send an alarm signal to the
controller, both free cooling dampers will open
(regardless of temperature) to dilute the shelter air.
• Freezestat – If coil temperature below 30°F is
sensed by the freezestat, the compressor will
deactivate for 5 minutes, or until the sensor sees
55°F, whichever comes first.
• Generator Run – During generator operation, the
system may limit compressor operation to only one
unit providing that a specific jumper was removed
from the LC controller terminal block and the
alarm wires were connected to a generator-run
relay (please refer to the Installation section of this
manual regarding alarms and wiring).
Power Outputs:
• 24VDC power to Bard-supplied hydrogen detector
through terminals 3 (+) and 4 (-). The + terminal
block is fused internally (see Componentry
section).
• 24VDC power to smoke detector through terminals
6 (+) and 7 (-). The + terminal block is fused
internally (see Componentry section).
• -24VDC power to generator run relay contacts (if
available) on terminal 9.
Detector Return Voltages:
• -24VDC signal from hydrogen detector on terminal
5 (always energizes hydrogen alarm isolation relay;
de-energizes on alarm).
• -24VDC signal from smoke detector on terminal 8
(always energizes smoke alarm isolation relay; de-
energizes on alarm).
• -24VDC signal from generator run contacts on
terminal 10 (always energizes generator run alarm
isolation relay; de-energizes on alarm).
Signal Inputs:
• 10K ohm remote indoor temperature sensor on
terminals 11 and 12.
• 10K ohm optional remote indoor temperature
sensor on terminals 13 and 14.
• 10K ohm optional remote indoor temperature
sensor on terminals 15 and 16.