GE 5500 manual Central Desk Control

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	Maximum Allowable Length
#22	600 Ft.
#20	900 Ft.
#18	1500 Ft.
#16	2000 Ft.

Freeze SentinelTM 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.

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	Unit #3
INCORRECT Common Bussing
	Normally Open
	Switch -
	Unit Operational
	CDC Terminals
	on Zoneline
	Typical Wiring
(All Wiring Shown Is Field Supplied)

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