Honeywell EXCEL 5000 User Manual page 241

EXCEL CARE CONTROL ICONS ALPHABETIC REFERENCE
If the lowest zone temperature is in this range, ZEB enables heating, that is, it
assigns 1 to YD1.
Example:
Maximum zone temperature X1 = 68
Minimum zone temperature X2 = 61
Average zone temperature X3 = 66
Comfort range P3 = 4FDeg
Max. heating setpoint P6 = 95
Heating reset range P11 = 27FDeg
ZEB Dehumidification
When the ZEB/Load reset mode in the internal parameters dialog box is equal to 1
(ZEB), 3 (Cooling control), or 4 (Heating and cooling), the application also includes
dehumidification as follows.
If the humidity measured by the X4 sensor exceeds the value of P10 (Room
humidity limit), ZEB initiates cooling. Relative humidity is the determining factor for
cooling.
If you select an absolute humidity sensor in the internal parameters dialog box, ZEB
performs a conversion to relative humidity.
To monitor humidity, select the With humidity sensor option in the internal
parameters dialog box.
Note that with Heating and cooling applications (ZEB/Load reset mode equal to 4),
ZEB only initiates cooling. This option does not inactivate heating. Cooling
condenses moisture in the air so that it can then be removed. Because heating is
still active, a downstream air heater can bring fresh air to the required temperature
again.
With the ZEB application (ZEB/Load reset mode equal to 1), cooling takes place
with a simultaneous inactivation of heating. In addition, setpoint management
engages the mixed air dampers and demands a setpoint for the dampers
determined by the maximum zone temperature.
With the Cooling control application (ZEB/Load reset mode equal to 3), when air
humidity exceeds the allowable value, ZEB only initiates cooling.
ZEB Example See the System Regulation application in the Examples chapter for a description of
a partial air conditioning system with mixed air dampers, an air heater, and an air
cooler. Setpoint management using the ZEB statement followed by PID controllers
regulates this system.
243 74-5577–33 (US)
EN2B-0184 GE51 R0518 (Europe)