Bryant DURAPAC PLUS SERIES 542J, Инструкция по установке, запуску и обслуживанию

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Minimum Position Control
There is a minimum damper position potentiometer on the
EconoMi$erIV controller. See Fig. 23. The minimum damper
position maintains the minimum airflow into the building
during the occupied period.
When using demand ventilation, the minimum damper posi-
tion represents the minimum ventilation position for VOC
(volatile organic compound) ventilation requirements. The
maximum demand ventilation position is used for fully occu-
pied ventilation.
When demand ventilation control is not being used, the min-
imum position potentiometer should be used to set the occu-
pied ventilation position. The maximum demand ventilation
position should be turned fully clockwise.
Adjust the minimum position potentiometer to allow the
minimum amount of outdoor air, as required by local codes,
to enter the building. Make minimum position adjustments
with at least 10° F temperature difference between the out-
door and return-air temperatures.
To determine the minimum position setting, perform the
following procedure:
1. Calculate the appropriate mixed-air temperature
using the following formula:
T
O
= Outdoor-Air Temperature
OA = Percent of Outdoor Air
T
R
= Return-Air Temperature
RA = Percent of Return Air
T
M
= Mixed-Air Temperature
As an example, if local codes require 10% outdoor air
during occupied conditions, outdoor-air temperature
is 60 F, and return-air temperature is 75 F.
(60 x .10) + (75 x .90) = 73.5 F
2. Disconnect the supply-air sensor from terminals T
and T1.
3. Ensure that the factory-installed jumper is in place
across terminals P and P1. If remote damper posi-
tioning is being used, make sure that the terminals
are wired according to Fig. 22 and that the minimum
position potentiometer is turned fully clockwise.
4. Connect 24 vac across terminals TR and TR1.
5. Carefully adjust the minimum position potentiometer
until the measured mixed-air temperature matches
the calculated value.
6. Reconnect the supply-air sensor to terminals T and T1.
Remote control of the EconoMi$erIV damper is desirable
when requiring additional temporary ventilation. If a
field-supplied remote potentiometer (Honeywell part num-
ber S963B1128) is wired to the EconoMi$erIV controller, the
minimum position of the damper can be controlled from a
remote location.
To control the minimum damper position remotely, remove
the factory-installed jumper on the P and P1 terminals on
the EconoMi$erIV controller. Wire the field-supplied potenti-
ometer to the P and P1 terminals on the EconoMi$erIV con-
troller. See Fig. 27.
Damper Movement
Damper movement from full open to full closed (or vice
versa) takes 2
1
/
2
minutes.
Thermostats
The EconoMi$erIV control works with conventional thermo-
stats that have a Y1 (cool stage 1), Y2 (cool stage 2), W1
(heat stage 1), W2 (heat stage 2), and G (fan). The
EconoMi$erIV control does not support space temperature
sensors. Connections are made at the thermostat terminal
connection board located in the main control box.
Occupancy Control
The factory default configuration for EconoMi$erIV control
is occupied mode. This is implemented by the RED jumper at
TB2-9 to TB2-10. When unoccupied mode is desired, remove
the RED jumper and install a field-supplied timeclock
function between TB2-9 and TB2-10. When the timeclock
contacts are open, the unit control will be in unoccupied
mode; when the contacts are closed, the unit control will be
in occupied mode.
Demand Controlled Ventilation (DCV)
When using the EconoMi$erIV for demand controlled venti-
lation, there are some equipment selection criteria which
should be considered. When selecting the heat capacity and
cool capacity of the equipment, the maximum ventilation
rate must be evaluated for design conditions. The maximum
damper position must be calculated to provide the desired
fresh air.
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
occupancy, and equipment that cannot exceed the required
ventilation rate at design conditions. Exceeding the required
ventilation 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.
In order to have the CO
2
sensor control the economizer damper
in this manner, first determine the damper voltage output for
minimum or base ventilation. Base ventilation is the ventila-
tion required to remove contaminants during unoccupied peri-
ods. The following equation may be used to determine the
percent of outside-air entering the building for a given damper
position. For best results there should be at least a 10 degree
difference in outside and return-air temperatures.
T
O
= Outdoor-Air Temperature
OA = Percent of Outdoor Air
T
R
= Return-Air Temperature
RA = Percent of Return Air
T
M
= Mixed-Air Temperature
(T
O
x
OA
) + (TR x
RA
) = T
M
100 100
(T
O
x
OA
) + (TR x
RA
) = T
M
100 100