Heating + Cooling Sequence Control With Zero Energy Band - Honeywell T2798I2000 Manual

Heating + Cooling Sequence control with Zero Energy Band

This kind of control requires Zero Energy Band (Z-Band). Z-Band is pre-set. For control purpose,
the zero energy band is centered on the user set point (SP), so its value defines the effective
heating (H SP) & cooling (C SP) set points. The cooling set point (C SP) will be positioned on
the right side of Z-Band & the heating set point (H SP) on the left side of Z-Band. Z-Band can be
set as 1.5° C or 3.0° C. Any change of set point will cause both heating and cooling set points to
change in parallel. Either output1 or output2 can be used for cooling or heating control. The
control logic is seen in Diagram 2 and 3.
Diagram 2: Heating + Cooling Sequence Control.
Output 1
Heating
Valve Open
100%
50%
Valve Close
0%
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H SP
SP
Z-Band
C SP
Output 2
Cooling
Diff
Temperature Increase
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