Central Desk Control; Typical Wiring - GE 5500 Data Manual

Central Desk Control

Some installations may want to govern the ability of the unit
to operate from a control device remote to the unit or even
remote to the room in which the unit is located. The
general term given to systems such as this is Central Desk
Control. The most common installation of this type of
system is a switch mounted at the registration desk and,
upon guest check-in, a button is pushed or a switch is moved
to allow the air conditioner to operate. Likewise, when the
guest checks out, the device is put into the "OFF" position so
the unit will not operate while the room is vacant.
It is not necessary that the controlling device be located at a
central desk to employ a device that will control the unit
operation. For instance, in some resort areas, devices are
connected to sliding glass doors and opening the door
causes a contact to close, turning the air conditioner off.
This prevents energy being wasted by operating the air
conditioner when warm humid air is entering the room.
Some systems operate by motion sensors or heat sensing
detectors mounted in the room. These types of systems
determine occupant presence in the room and allow the
unit to operate; if no one is in the room, the device signals
the air conditioner to turn off.
Zoneline models offer Load Shedding capabilities on units
connected to Central Desk Control Systems. For more
information on the Models' Load Shedding Feature, see
page 10.
All Zoneline 2500, 3500, and 5500 Series units are
compatible with simple on/off 2 wire Central Desk Control
systems. Consult with the provider of other energy
management systems to be sure they are compatible with the
GE Zoneline units. Zoneline units have standard connectors
factory installed to provide a CDC interface that permits the
unit to be connected to most energy management systems.
The devices connected to the Zoneline units require no
power supply or transformers external to the unit.
Important CDC Comments (all series applicable)
1) When the switching device closes the circuit of the CDC
conductors, the unit operation stops.
2) Do not use a common buss (at the unit or at the switch
panel) in the wiring. Both wires comprising the circuit
must connect to the unit connectors and to the
controlling switch. Running one wire from one unit to
another unit is common bussing and may damage
internal components or cause erratic operation of the
system.
3) A 24 volt transformer is contained within the Zoneline
units. No external voltage may be applied to the unit through
the CDC terminals. (Voltage on the CDC conductors is
24 volts AC.)
4) Recommended wire size must be followed as a minimum
requirement.
Wire Size #AWG
#22
#20
#18
#16
Freeze Sentinel TM remains operational when the unit is
connected to a CDC system. Even if the unit is turned "OFF"
at the central location, if the sensor at the unit detects the
low temperature, the electric resistance heaters and fan will
automatically turn on.
14
Maximum Allowable Length
600 Ft.
900 Ft.
1500 Ft.
2000 Ft.
Connecting the Zoneline unit to a CDC system does not
eliminate the ability to connect the unit to a remote
thermostat. Once the circuit is "opened", and control of the
unit removed from the CDC system, the selected controls -
either the unit mounted control or the remote thermostat -
govern the operation of the unit.
Please see page 57 for installation recommendations for the
Central Desk Control wiring.
CDC Terminal Location and Typical Wiring
See page 12 and 13 for location of CDC terminals on unit
Example of Common Bussing
NOT PERMITTED
Unit #1 Unit #2
INCORRECT Common Bussing
Normally Open
Switch -
Unit Operational
CDC Terminals
on Zoneline

Typical Wiring

(All Wiring Shown Is Field Supplied)
Unit #3