Bryant 581C024--060 - Manual (Page 25)

25
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
C06039
Fig. 40 --- CO
2
Sensor Maximum Range Setting
CO
2
Sensor Configuration
The CO
2
sensor has preset standard voltage settings that can be
selected anytime after the sensor is powered up. (See Table 7.)
Use setting 1 or 2 for Bryant equipment. (See Table 7.)
1. Press Clear and Mode buttons. Hold at least 5 seconds
until the sensor enters the Edit mode.
2. Press Mode twice. 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.
5. Press Mode to exit and resume normal operation.
The custom settings of the CO
2
sensor can be changed anytime
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 seconds
until the sensor enters the Edit mode.
2. Press Mode twice. 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.
Dehumidification of Fresh Air with DCV Control
Information from ASHRAE indicates that the largest humidity
load on any zone is the fresh air introduced. For some
applications, a device such as an energy recovery unit can be
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 processes are more than
adequate to remove the humidity loads for most commercial
applications.
If normal rooftop heating and cooling operation is not adequate
for the outdoor humidity level, an energy recovery unit and/or a
dehumidification option should be considered.
Step 9 —Adjust Evaporator--Fan Speed
Adjust evaporator-fan speed to meet jobsite conditions.
Tables 8 and 9 show fan rpm at motor pulley settings. Tables 10
and 14 show maximum amp draw of belt-drive motor. Table 13
shows sound data. Refer to Tables 15--34 for performance data.
See Table 11 for accessory static pressure drop. See Fig. 41 for
the Perfect Humidity™ system static pressure drops.
Belt Drive Motors
Fan motor pulleys are factory set for speed shown in Table 1 or 2.
Check pulley alignment and belt tension prior to start-up.
To change fan speed:
1. Shut off the unit power supply and tag disconnect.
2. Loosen the belt by loosening the fan motor mounting nuts.
(See Fig. 42.)
3. Loosen movable pulley flange setscrew. (See Fig. 43.)
4. Screw movable flange toward fixed flange to increase
speed and away from fixed flange to decrease speed.
Increasing fan speed increases load on motor. Do not
exceed maximum speed specified in Table 1 or 2.
5. Set movable flange at nearest keyway of pulley hub and
tighten setscrew. (See Table 1 or 2 for speed change for
each full turn of pulley flange.)
6. Adjust belt tension and align fan and motor pulleys per
guidance below.
NOTE: Once the required flange position is determined for the
correct blower rpm, it is recommended (bu not required) that the
variable pitch pulley be replaced with a corresponding size fixed
sheave pulley.
To align fan and motor pulleys, loosen fan pulley setscrews and
slide fan pulley along fan shaft. Make angular alignment by
loosening motor from mounting.
Additional motor and fan alignment, as well as angular alignment
can be made by loosening the four motor mounting bolts from
the mounting plate.
To adjust belt tension:
1. Loosen the two motor mounting nuts as shown in Fig. 42.
Some models may have a third mounting nut located on
the opposite side of the fan motor mounting plate.
2. Slide motor mounting plate away from fan scroll for
proper belt tension ( 1 /
2
-in. deflection with 8 to 10 lb of
force) and tighten mounting nuts.
3. Adjust lock bolt and nut on mounting plate to secure
motor in fixed position.
581B
,C