5 WIRE CONDUCTOR
(INTERFACE BOARD)
3 WIRE CONDUCTOR
(COMM BUS)
COMM BUS
GRN | GREEN |
RED | RED |
|
WHT | WHITE |
|
RED | RED |
|
YEL | YELLOW |
|
BLU | BLUE |
|
GRN | GREEN |
WHT | WHITE |
FIELD WIRING | |
(FEED THRU) | |
I/O BOARD | |
Fig. 17ÐWiring Four Zone Controller A93231
Changing the base temperatures will change the Comfort Temperature Setpoints used in the system schedules. Always set the Base Temperatures prior to programming the system schedules.
Comfort Zone also uses a minimum temperature and a maximum temperature for comfort setpoints. The minimum and maximum temperatures are the same for all 4 zones.
The Maximum Temperature is only used for cooling. It is set by selecting Rotary Switch Position S-2. The Maximum Temperature setting is used when a temperature above the 14° span is selected. If Cooling Base Temperature is set to 68°F and cooling setpoint is 82°F, any attempt to raise cooling setpoint will select Maximum Temperature.
The Minimum Temperature is only used for heating. It is set by selecting Rotary Switch Position S-3. The Minimum Temperature setting is used when a temperature below the 14 ° span is selected. If Heating Base Temperature is set to 54°F, any attempt to lower heating setpoint below 54°F will select Minimum Temperature.
Both Maximum and Minimum Temperatures are intended for use with schedules or setpoints which are extreme compared to normal building temperatures.
Comfort Zone also has one additional set of temperature settings. These are Vacation Setpoints. The Vacation Setpoints are heating and cooling setpoints to be used in all 4 zones whenever 4 zone controller rotary switch is turned to "Vacation." The Vacation option is used to place entire building in setback during long unoccupied periods without danger of freezing or extreme heat/humidity.
SEQUENCE OF EVENTS FOR A NORMAL HEATING OR COOLING CYCLE
Given Comfort Setpoints and space temperature for zones within system, Comfort Zone will determine if active heating or cooling is required. If so, Comfort Zone will perform the following:
1.Select a reference zone.
2.Make sure all zone dampers are fully open.
3.Energize HVAC equipment fan.
4.Energize heating or cooling equipment. The equipment may be a compressor, furnace, strip heater, etc.
5.Set the zone damper positions based upon zone demand.
6.Energize additional stages of heating or cooling if demand warrants.
7.Continue to adjust zone dampers as conditions within zones change.
8.Turn off heating or cooling equipment when all zones are within 0.5°F of desired comfort setpoint.
9.Open all zone dampers when equipment is turned off.
This is the basic Sequence of Operation for the Comfort Zone system. The actual control of dampers, HVAC equipment, and system fan will change with configuration of system. Depending upon configuration, Comfort Zone can control heat pumps, fur- naces, and dual fuel applications.
SELECTION OF A REFERENCE ZONE IN THE SYSTEM
The first step in any heating or cooling cycle requires Comfort Zone to evaluate zones, determine if heating or cooling is needed, and select a Reference Zone.
The Comfort Zone system actively looks at Comfort Setpoints and space temperature in all zones. If any zone in system has a demand of 1.5°F or more, then Comfort Zone will prepare to operate heating or cooling equipment to reduce demand.
First, Comfort Zone will select a reference zone in the system. The reference zone will be zone with greatest demand. The zone damper serving reference zone will be forced fully open and will remain fully open as long as that zone is used as reference.
As long as any zone in system has a demand greater than or equal to 1.5°F, then Reference Zone will be selected by zone with greatest demand. Once all zones have a demand less than 1.5oF, Reference Zone selection will not change until demand in that zone is below 0.5°F. At this point Comfort Zone will re-select Reference Zone and position that particular zone damper fully open.
The objective of Reference Zone is to ensure that zone with greatest demand is receiving as much conditioned air as system will allow. It also gives Comfort Zone system a point of reference in observing response of zones to equipment operation.
PRE-POSITIONING DAMPERS AND STARTING THE SYSTEM FAN
In order to minimize noise and enhance system operation, Comfort Zone maintains all zone dampers full open prior to starting system fan or heating or cooling equipment. The intent is to provide HVAC equipment with unrestricted duct work and reduce pressure surges. Comfort Zone also fully opens dampers whenever a heating or cooling cycle is completed and system fan is shutting down. If Fan Switch on 4 zone controller is set to Auto, then all zone dampers will remain fully open until next heating or cooling cycle.
The other reason for opening dampers is to provide unrestricted duct work to other equipment which is not directly controlled by Comfort Zone. One example may be Heat Recovery Ventilator. If Comfort Zone is not actively controlling HVAC system, then it must not impose any control influences (i.e., closed zone dampers) on system and prevent proper operation of other devices.
For Fan operation, switch settings on 4 zone controller and system configuration can change actual operation.
If Auto Fan Off For Heating option (Rotary switch position number T-9) is ON, then Comfort Zone will only energize fan for cooling cycles. This option is intended for furnaces which will control their own fan internally.