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Manual 2100-746

Page 27 of 55

FIGURE 10

Cooling with Six Single Stage Units (w/Economizers) Using Twinning/Pairs Option

The Advantages of Twinning: Pairs

Using the same number of units as shown in Figure

9 on page 25 (six units w/economizers) and selecting

the Pairs option in Twinning, the number of stages can

be reduced to six by engaging two units per stage (see

Figure 10). This reduces the temperature range in the

building by 50% as well (5°F).

FIGURE 11

Cooling with Six Single Stage Units (w/Economizers) Using Twinning/Triples Option

By pairing units, the temperature spread to bring on all resources goes from 11°F down to 5°F.

78.0 80.0 82.0

74.0 76.0

Stage 1

75.0

77.0 79.0 81.0 83.0

Stage 2

Stage 3

Stage 4

Stage 5

Stage 6

Cooling

Cooling Deadband

Off

Defaults

Setpoint: 77°F

Interstage Differential: 1°F

Off Differential: 2°F

The Advantages of Twinning: Triples

Using the same number of units and selecting the

Triples option in Twinning, the number of stages can be

reduced to four and the space temperature narrowed

even more, from singles (77°F to 88°F, 11°F total)

to pairs (77°F to 82°F to, 5°F total) to triples (77°F

to 83°F, 3°F total) as shown in Figure 11. Be sure to

consider the total number of stages and choose the

best option for the speciﬁcations.