Manual 2100-746D
Page
30 of 59
FIGURE 14
Twinning: Simultaneous Unit Operation
STAGE
1
Twinning can reduce the number of stages required to bring on resources keeping the interstage differential range tighter.
For example: Using 77°F as a set point and controlling six units with economizers will have 12 stages. If there is a .5°F
interstage differential, there will be 6°F between set point and last stage on, making a 77°F run under full load at 83°F. By
twinning, the control reduces the number of stages to six and the resulting temperature spread to 3°F or 80°F.
NOTE:
All units connected in "home run" configuration only.
STAGE
1
STAGE
2
STAGE
2
STAGE
3
STAGE
3
Twinning: Simultaneous Unit Operation
See Figure 14.
• Units operate simultaneously: Off ALL Pairs
Triples
• Units stage on and off in their assigned groups
(two or three)
• Available for four or six units only (MC5600
required)
• User-selectable setup where two or three units
start/count as one stage
NOTE:
Even though two or three units count as a
stage and are cycled together, there will be a
5-second delay between units.
• Paired – Only available with four or six units. Units
will operate in pairs.
• Four total units: Units 1 and 2 will stage
simultaneously and units 3 and 4 will stage
simultaneously. Lead/lag rotation will be in pairs.
• Six total units: Units 1 and 2 will stage
simultaneously, units 3 and 4 will stage
simultaneously and units 5 and 6 will stage
simultaneously. Lead/lag rotation will be in pairs.
• Lead would be units 1 & 2, 3 & 4 or 5 & 6. Lead
will still rotate one unit at a time. When unit 1 or 2
is lead, 1 & 2 will be lead, and so on.
