Level increases even though the co, Set point has not been reached. by the time the co, Fig. 41 — enthalpy changeover set points – Carrier 48TM016-028 User Manual

Page 29: Fig. 42 — economi$eriv controller, Fig. 43 — co, Sensor maximum range setting

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29

Typically the maximum ventilation rate will be about 5 to

10% more than the typical cfm required per person, using
normal outside air design criteria.

A proportional anticipatory strategy should be taken with

the following conditions: a zone with a large area, varied occu-
pancy, and equipment that cannot exceed the required ventila-
tion rate at design conditions. Exceeding the required ventila-
tion rate means the equipment can condition air at a maximum

ventilation rate that is greater than the required ventilation rate
for maximum occupancy. A proportional-anticipatory strategy
will cause the fresh air supplied to increase as the room CO

2

level increases even though the CO

2

set point has not been

reached. By the time the CO

2

level reaches the set point, the

damper will be at maximum ventilation and should maintain
the set point.

CONTROL

CURVE

A
B
C
D

CONTROL POINT

APPROX. °F (°C)

AT 50% RH

73 (23)
70 (21)
67 (19)
63 (17)

12

1

4

1

6

1

8

2

0

2

2

2

4

26

28

30

32

3

4

3

6

3

8

40

42

4

4

46

90

10

0

80

70

60

50

40

30

20

10

ENT

HA

LP

Y—

BTU

P

ER

PO

UN

D DR

Y A

IR

85

(29)

90

(32)

95

(35)

100

(38)

105

(41)

110

(43)

35

(2)

35

(2)

40

(4)

40

(4)

105

(41)

110

(43)

45

(7)

45

(7)

50

(10)

50

(10)

55

(13)

55

(13)

60

(16)

60

(16)

65

(18)

65

(18)

70

(21)

70

(21)

75

(24)

75

(24)

80

(27)

80

(27)

85

(29)

90

(32)

95

(35)

100

(38)

APPROXIMATE DRY BULB TEMPERATURE— °F (°C)

A

A

B

B

C

C

D

D

R

EL

AT

IVE

H

U

M

ID

IT

Y

(%

)

HIGH LIMIT
CURVE

Fig. 41 — Enthalpy Changeover Set Points

TR1

24 Vac

COM

TR

24

Vac

HOT

1

2

3

4

5

EF

EF1

+

_

P1

T1

P

T

N

EXH

2V

10V

EXH

Set

Set

2V

10V

2V

10V

DCV

DCV

Free
Cool

B

C

A

D

SO+

SR+

SR

SO

AQ1

AQ

DCV

Min
Pos

Open

Max

N1

Fig. 42 — EconoMi$erIV Controller

0

1000

2000

3000

4000

5000

6000

2

3

4

5

6

7

8

800 ppm

900 ppm

1000 ppm

1100 ppm

RANGE

CONFIGURA

TION

(ppm)

DAMPER VOLTAGE FOR MAX VENTILATION RATE

CO SENSOR MAX RANGE SETTING

2

Fig. 43 — CO

2

Sensor Maximum Range Setting

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