APPLICATION DATA (cont)

IAQ sensors — EconoMi$erIV can be utilized with any IAQ (CO2) sensor that provides a 2 to 10 vdc output. The con- troller will modulate the outdoor air damper to provide venti- lation based on the sensor output and the IAQ setting of the controller. When used, an IAQ sensor will modulate the damper from the minimum position (base ventilation rate based on CO2 levels) to maximum position (full occupancy ventilation rate).

Damper operation — The EconoMi$erIV allows the damper to be configured for two adjustable damper positions includ- ing maximum position and occupied minimum positions. The two (2) position damper capability is a unique feature of EconoMi$erIV and includes operation flexibility as follows:

1.Minimum Occupied Position: This adjustable position allows a minimum ventilation airflow rate through the unit during occupied periods (base ventilation rate).

2.Demand Control Ventilation (DCV) Maximum Position: A DCV maximum occupied position is provided when using an IAQ sensor for DCV. See DCV and Control sections for sequence. The DCV Maximum Position limits outdoor airflow into the rooftop when the DCV routine overrides the mixed air sensor. Setting the DCV Maximum Position of the outdoor-air damper prevents large amounts of hot or cold air into the space.

IMPORTANT: When the DCV Maximum Position is set below the minimum position, the minimum position over- rides the maximum position, negating most DCV functions.

Compressor staging — The EconoMi$erIV is an integrated economizer and has the ability to utilize simultaneous out- door air and compressors. The EconoMi$erIV can be con- figured to support economizer and compressor operation for up to 4 compressors. Only one or two compressor oper- ation is available with 3 to 121/2 ton units.

CHANGEOVER STRATEGIES — The EconoMi$erIV con- troller can be configured to accommodate all available economizer control strategies that place the rooftop unit in economizer mode including:

Switch — Used when a remote signal from an energy man- agement system will enable and disable the EconoMi$erIV (remote enable control).

Outdoor dry bulb — EconoMi$erIV will be enabled based on the outside air temperature. This is provided standard with the EconoMi$erIV.

Differential dry bulb — EconoMi$erIV will be enabled when- ever the outside air temperature is lower than the return-air temperature.

85

90

95

100

105

110

(29)

(32)

(35)

(38)

(41)

(43)

CONTROL

CURVE

A

B

C

D

1

8

 

1

6

 

1

4

 

1

2

 

CONTROL POINT

APPROX. °F (°C)

AT 50% RH

 

73 (23)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

40

 

70 (21)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

IR

 

 

67 (19)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Y

A

3

8

 

63 (17)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

DR

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

D

 

 

3

6

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

N

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

U

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

PO

 

3

4

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

P

E

R

32

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

TU

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

B

 

30

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

P

Y

28

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

L

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

HA

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

26

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

NT

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

65

 

 

E

2

4

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

(18)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

2

2

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

60

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

2

0

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

(16)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

A

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

55

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

(13)

 

B

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

50

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

C

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

(10)

 

 

 

 

 

 

 

 

 

45D

(7)

40

(4)

35

(2)

4

4

 

42

70

(21)

1

0

0

 

0

 

9

 

 

 

 

 

 

46

80 (27)

75

(24)

80

70

 

6

0

 

50

D C B A

4

0

 

 

A

T

IVE

REL

 

 

 

 

 

 

3

0

 

 

 

 

 

 

%

)

 

 

 

Y

(

 

 

 

 

 

 

 

 

IDIT

 

 

 

HU

M

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

20

0 1

HIGH LIMIT

CURVE

a50-7751

35

40

45

50

55

60

65

70

75

80

85

90

95

100

105

110

(2)(4) (7) (10) (13) (16) (18) (21) (24) (27) (29) (32) (35) (38) (41) (43)

APPROXIMATE DRY BULB TEMPERATURE— °F (°C)

Economizer Changeover Curves

167

Page 167
Image 167
Bryant 549C manual Economizer Changeover Curves, B a, Approximate DRY Bulb TEMPERATURE- F C