Bryant DuraPac Series 580f User Manual download pdf (Page 23)

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minimum position (configuration item number 15), unless

the remote potentiometer is used to override it.

For the demand ventilation control logic, the user configures

the lower and upper actuator position to establish the base

ventilation rate (IAQMIN_SP) and the design ventilation

rate (ECONOMIN_SP) for full occupancy. When the

EconoMi$er+ damper is being modulated for demand venti-

lation control, the damper position will be between

IAQMIN_SP and ECONOMIN_SP. The upper IAQ differen-

tial set point is DAQHI. The lower IAQ differential set point

is DAQLO.

The differential set points represent the differential CO

level (in ppm) above the outdoor reference IAQ levels.

Normally, the outdoor reference IAQ levels are around

400 ppm, but the value should be configured based on the

reference levels taken at the job site.

The following equation is used to determine EconoMi$er+

damper position (ECONOMIN_POS):

R. CO

Sensor Configuration

The CO

sensor has preset standard voltage settings that

can be selected anytime after the sensor is powered up. See

Table 7.

1. Press Clear and Mode buttons. Hold at least 5 sec-

onds until the sensor enters the Edit mode.

2. Press Mode 2 times. The STDSET Menu will appear.

3. Use the Up/Down button to select the preset number.

See Table 7.

4. Press Enter to lock in the selection.

Press Mode to exit and resume normal operation. The cus-

tom settings of the CO

sensor can be changed any time

after the sensor is energized. Follow the steps below to

change the non-standard settings:

1. Press Clear and Mode buttons. Hold at least 5 sec-

onds until the sensor enters the Edit mode.

2. Press Mode 2 times. The STDSET Menu will appear.

3. Use the Up/Down button to toggle to the NONSTD

menu and press Enter.

4. Use the Up/Down button to toggle through each of

the nine variables, starting with Altitude, until the

desired setting is reached.

5. Press Mode to move through the variables.

6. Press Enter to lock in the selection, then press Mode

to continue to the next variable.

S. Dehumidification of Fresh Air with Demand Control Ven-

tilation (DCV)

Information from ASHRAE (American Society of Heating,

Refrigeration and Air Conditioning Engineers) indicates that

the largest humidity load on any zone is the fresh air intro-

duced. For some applications, a device such as a energy

recovery unit is added to reduce the moisture content of the

fresh air being brought into the building when the enthalpy

is high. In most cases, the normal heating and cooling pro-

cesses are more than adequate to remove the humidity loads

for most commercial applications.

This makes the control of the dehumidification device simple

when using the enthalpy or differential enthalpy sensor. The

enthalpy sensor or differential enthalpy sensor is installed

on the equipment to determine economizer operation. The

high enthalpy signal from the temperature and humidity

sensors or differential temperature and humidity sensors

can be used to turn on the outdoor air moisture removal

device any time fresh air is required for the space.

The energy recovery device should be sized for maximum

latent and sensible conditioning at maximum ventilation on

a design day.

A calculation for leaving-air temperature on a low ambient,

low ventilation day should also be done to determine the

supply-air temperature of the return and pre-conditioned

outside air. The design should produce air temperature

somewhat near room conditions to prevent reheat of the air

mixture. The energy recovery device should be interlocked

with the heat to turn off the device when in the heat mode.

Table 7 — CO

Sensor* Standard Settings

LEGEND

*Available sensor part numbers are listed in Table 4.

IAQMIN_SP +=

(ECONOMIN_SP – IAQMIN_SP) * (IAQ – OAQ – DAQLO)

(DAQHI – DAQLO)

SETTING EQUIPMENT OUTPUT

VENTILATION

RATE

(cfm/Person)

ANALOG

OUTPUT

CONTROL

RANGE (ppm)

OPTIONAL

RELAY SETPOINT

(ppm)

RELAY

HYSTERESIS

(ppm)

Interface with Standard

Building Control System

Proportional Any 4-20 mA 0-2000 1000 50

2 Proportional Any 7-20 mA 0-2000 1000 50

3 Exponential Any 4-20 mA 0-2000 1100 50

Economizer

Proportional 15 4-20 mA 0-1100 1100 50

5 Proportional 20 4-20 mA 0- 900 900 50

6 Exponential 15 4-20 mA 0-1100 1100 50

7 Exponential 20 4-20 mA 0- 900 900 50

8 Health & Safety Proportional — 4-20 mA 0-9999 5000 500

9 Parking/Air Intakes/ Loading Docks Proportional — 4-20 mA 0-2000 700 50

ppm — Parts Per Million

100

500

700

1100

INSIDE/OUTSIDE CO

DIFFERENTIAL

INSIDE CO

CONCENTRATION

DIFFERENTIAL

LOW (DAQLO)

DIFFERENTIAL

HIGH (DAQHI)

IAQ

MINIMUM

ECONOMIZER

POSITION

SET POINT

(IAQMIN_SP)

ECONOMIZER

MINIMUM

OCCUPIED

DAMPER

POSITION

(ECONOMIN_SP)

VENTILATION FOR PEOPLE

VENTILATION FOR SOURCES

FULL OCCUPANCY

VENTILATION RATE

DAMPER

POSTION

CO LEVEL

OUTDOOR REFERENCE

LEVEL (OAQ)= 400

Fig. 32 — Demand Ventilation Control

1 2 ... 18 19 20 21 22 23 24 25 26 27 28 ... 63 64

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Bryant DuraPac Series 580f User Manual Page 23

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