80.5
80.076.0 78.0
Unit 1
Stage 1
77.0 79.579.0 81.0
On
Off Differential
Off
76.5 77.5 78.5
Unit 2
Stage 1
Unit 3
Stage 1
Manual 2100-746
Page 28 of 55
Humidification/Dehumidification Demand Staging
Humidification staging begins when the space humidity
is less than the humidification set point. Staging will
increase when the space humidity is less than the
humidification set point and humidification interstage
differential combined. Staging increases will continue
each time space humidity decreases greater than
the humidification interstage differential setting.
Humidification stage decreases will happen inversely to
the staging increases.
Dehumidification staging begins when the space
humidity is greater than the dehumidification set
point. Staging will increase when the space humidity
is greater than the dehumidification set point and
dehumidification interstage differential combined.
Staging increases will continue each time space
humidity increases greater than the dehumidification
interstage differential setting. Dehumidification
stage decreases will happen inversely to the staging
increases.
FIGURE 12
Cooling without Economizer
Alternating and Non-Alternating Setup
Alternating/Non-Alternating Logic
The MC5000 series controller offers two staging
sequence options: Alternating (default) or Non-
Alternating.
Alternating
Alternating Logic will be the default for this controller.
In the Alternating Logic stage, increases will start
with the lead unit for the first stage and then alternate
to the next available unit for sequential stages.
Decreases in staging will happen in the exact opposite
sequence. See example of a 3-unit system with 2 stage
compressor and economizer in Table 2.
TABLE 2
Alternating Logic: 3-Unit System with 2 Stage
Compressor and Economizer
Stage Unit 1 Unit 2 Unit 3
1 Y1 OFF OFF
2 Y1 Y1 OFF
3 Y1 Y1 Y1
4 Y1, Y2 Y1 Y1
5 Y1, Y2 Y1, Y2 Y1
6 Y1, Y2 Y1, Y2 Y1, Y2
TABLE 3
Non-Alternating Logic: 3-Unit System with 2 Stage
Compressor and Economizer
Stage Unit 1 Unit 2 Unit 3
1 Y1 OFF OFF
2 Y1, Y2 OFF OFF
3 Y1, Y2 Y1 OFF
4 Y1, Y2 Y1, Y2 OFF
5 Y1, Y2 Y1, Y2 Y1
6 Y1, Y2 Y1, Y2 Y1, Y2
Cooling without Economizer
Non-Alternating
Non-Alternating Logic stage increases will start with
the lead unit and exhaust all available stages prior to
staging the next unit. Decreases in staging will happen
in the exact opposite sequence. See example of a
3-unit system with 2 stage compressor and economizer
in Table 3.