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Heating+CoolingSequencecontrolwithZeroEnergyBand
This kindof control requiresZeroEnergyBand (Z-Band). Z-Band is pre-set. For control purpose,
the zeroenergy band is centeredon theuser set point (SP), so its valuedefines theeffective
heating (HSP) & cooling (CSP) set points. The cooling set point (CSP)will bepositionedon
the right sideof Z-Band& theheating set point (HSP) on the left sideof Z-Band. Z-Band canbe
set as1.5°Cor 3.0°C. Any changeof set point will causebothheatingand cooling set points to
change inparallel. Either output1or output2 canbeused for coolingor heating control. The
control logic is seen inDiagram2and3.
Diagram2: Heating +CoolingSequenceControl.
Z-Band
Output 2
Cooling
50%
Valve Open
100%
Temperature Increase
Valve Close
0%
SP
Output 1
Heating
Diff
HSP
C SP
