connect using two twisted pair cables, the first for power
connection. The LinkNet cable needs to be balanced 100
to 120 ohm nominal impedance twisted shielded pair
cable, nominal capacitance of 16 PF/FT or lower.
Units Supplied with an Electro-mechanical
Controls (EMC) Package
The EMC controls package or dry contact control op-
tion includes: all relays, motor starters, motor overloads,
damper actuators, heating and cooling initiate contacts
and selected option pickup points. All necessary con-
nections are wired to a terminal strip in the control panel
for field wiring connections to a building management
system, for field supplied DDC or standard controls and
thermostats. See the Control Contractor’s flow and wiring
schematics for connection details.
Ventilation Control Scheduling Modes
Occupied Ventilation (Ov)
If the occupancy contact closes or a jumper is placed
across terminals FW 304–305 this will enable the unit to
run in 100% fresh air mode. Free cooling and defrost will
initiate based on the setpoint.
Unoccupied Recirculation (Ur)
If the unoccupied recirculation contact closes or a jumper
is placed across terminals FW 305–306 the unit will turn
off unless there is a call for heating/cooling or dehumidi-
fication across the heating/cooling or dehumidification
contacts. This must come from an optional thermostat or
humidistat. The unit will run in recirc mode upon a call.
Occupied Recirculation (Or) (DDC Control Package
Only)
If the occupied recirculation contact closes or a jumper
is placed across terminals, heat wheel starts (not in free
cooling), defrost recirculation damper closes (if equipped),
outside and exhaust air dampers (if equipped) begin to
open; after outside air damper opens fully the supply
blower starts; after exhaust air damper opens fully the
exhaust blower starts, the occupied recirculation damper
opens and outside and exhaust dampers modulate to the
minimum setpoints.
Unoccupied (Un)
If the contact opens or jumper removed on any of the ter-
minals 304, 305, 306, 307 or 308 the unit will turn off.
PNL
FW
PNL
FW
Figure 2: Possible terminal strip locations in electrical
panel
VCES-VHC-IOM-1F – VHC-36, -42 & -50
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