Manual 2100-614I
Page
5 of 43
SPECIFICATIONS/FEATURES FOR BASIC
CONTROLLER
MC4002 Basic Controller
•Input power: 18-32 VAC, 60/50Hz, power is supplied from
A/C #1 and/or A/C #2
•Isolation circuitry: no line or low voltage phasing required
•Backup power: connection for -24 VDC or -48 VDC (-20
to -56V) maintains microprocessor operation, front panel
indication & alarm relay operation during commercial power
outages.
•Digital display: 4-character LCD
•Temperature display: F or C
•HVAC outputs: Form A (NO) relays (1A @ 24 VAC)
•Cooling control stages:
2 for each A/C unit (4 total) when configured for economizers
1 for each A/C unit (2 total) when configured for no economizers
•Heating Control stages:
1 for each A/C unit, 2 for each heat pump if so configured
•Dehumidification circuit: requires optional humidity
controller as input signal
•Operating temperature range: 0 to 120F (-18 to 49C)
•Storage temperature range: -20 to 140F (-29 to 60C)
•Temperature accuracy: +/- 1F from 60-85F (16-30C)
+/- 1% outside 60-85F
•Lead/lag changeover time: 0 to 30 days
•Timing accuracy: +/- 1%
•Inter-stage time delay: 10 seconds between stages
•Inter-stage differential:
Stage 1 to 2 - Range 2-6F, default is 4
Stage 2 to 3 - Range 2-3F, default is 2
Stage 3 to 4 - Range 2-3F, default is 2
•On-Off differential: 2F (1C) is standard, 4F (3C) when
“excessive cycling” mode is enabled
•Cooling setpoint range: 65 to 90F (18.3 to 32.2C)
•Comfort setting-Cooling 72F (22C), Heating 68F(20C), for
1 hour
•Dead band (difference between cooling and heating
setpoints): 2F to 40F (1.1C to 22.2C)
•Fire/smoke interface: standard NC circuit jumper, remove
for connection to building system control, shuts down
outputs to both A/C units immediately
•Memory: EEPROM for setpoint and changeable parameters
(maintains settings on power loss)
•Space temperature sensors: One (1) local is standard, will
accept up to twp (2) optional 35' remote sensors, Bard part
number 8612-023A. When multiple sensors are used,
temperatures are averaged
•Controller Enclosure: 20-gauge pre-painted steel, 9.25"W
x 13.50"H x 3.00"D, hinged cover, thirteen (13) .875"
diameter electrical knockouts
•LEDs for basic controller: Lead unit, Cooling stages 1
through 4, Heating Stages 1 – 4, Dehumidification operation
•Six (6) Push-button controls: On/Off switch-Change lead
unit-Increase and Decrease setpoints-Program/Save-Comfort.
MOUNTING THE CONTROLLER
Included in the controller carton is the controller and
installation instructions.
The controller should be installed on a vertical wall
approximately 4 feet above the floor-away from drafts and
outside doors or windows. Four (4) mounting holes are
provided for mounting to the wall and 7/8" holes for conduit
connections are provided in both the base, sides and top of
the controller.
TEMPERATURE SENSORS
The standard (local) temperature sensor has 12" leads and
comes installed from the factory.
A secondary sensor is located internally on the main controller
board and serves as a reference and back-up sensor to the
local sensor. If the difference between the two sensors is
less than the differential setpoint, the local sensor will be
used as the controller's temperature point of reference. The
differential is adjustable from 12-20°F. 12°F is the default
setting. If the difference between the two sensors is greater
than the differential set-point, then the controller will check
to determine if the on-board sensor is reading a temperature
that is between the SP (set-point), plus the differential and the
SP minus the DB (dead-band) minus the differential. If it is,
the on-board sensor will become the valid sensor reading and
the controller will ignore the local sensor reading. If not, then
the controller, will still use the local sensor reading. This is to
add additional levels of operational capability in the rare event
the local sensor fails. If the controller is operating in this
mode, it is indicated by the lower left decimal point flashing in
the display. If this feature is not desired, set the differential
set-point to OFF. This disables the on-board sensor. This may
be necessary if the controller is located in one room and the
local sensor has been relocated to a different room.
Note: For
purposes of testing when the local sensor is manually driven
higher or lower by applying warm or cool water to the probe the
on-board sensor is inhibited for the first 30-minutes following
power up, or when power is cycled off and back on.
The controller is designed to accept 1 or 2 additional sensors
and those have 35-foot leads. The Bard part number for the
optional sensor with 35-foot leads is 8612-023A. These can
be installed as required in the structure to address hot spots,
barriers to airflow, etc. If a remote sensor(s) is used, the on-
board sensor is disabled. The local sensor remains active.
It is recommended that the sensor lead wires be installed in
conduit for protective purposes.
TEMPERATURE SENSOR LOGIC
The standard local
(LSEn)
sensor monitors the temperature at
the controller location. If this is the only sensor connected,
it will control the temperature read-out, the space (building)
temperature, and also be used for Low and High Temperature
alarm functions.
If one or more
REMOTE
sensors are installed and connected
(
Rem 1
or
Rem 2
), the temperature read-out will display and
NOTE: All sensors are polarity sensitive. The
copper lead must connect to terminal CU, and the
silver lead to AG. Sensors are solid state, not RTD.
Use only sensors supplied by Bard. Sensor leads
can be extended up to 200 feet. Use 18-gauge
twisted pair with soldered connections.
