Operation, 607c -- -- a – Bryant 607C-A User Manual
Page 47
47
Table 16 – CO
2
Sensor Standard Settings
SETTING
EQUIPMENT
OUTPUT
VENTILATION
RATE
(CFM/
PERSON)
ANALOG
OUTPUT
CO
2
CONTROL
RANGE
(PPM)
OPTIONAL
RELAY
SETPOINT
(PPM)
RELAY
HYSTERESIS
(PPM)
1
Proportional
Any
0---10V
4---20mA
0---2000
1000
50
2
Interface w/Standard Building
Control System
Proportional
Any
2---10V
7---20mA
0---2000
1000
50
3
Exponential
Any
0---10V
4---20mA
0---2000
1100
50
4
Proportional
15
0---10V
4---20mA
0---1100
1100
50
5
Economizer
Proportional
20
0---10V
4---20mA
0---900
900
50
6
Exponential
15
0---10V
4---20mA
1---1100
1100
50
7
Exponential
20
0---10V
4---20mA
0---900
900
50
8
Health & Safety
Proportional
---
0---10V
4---20mA
0---9999
5000
500
9
Parking/Air Intakes/Loading Docks
Proportional
---
0---10V
4---20mA
0---2000
700
50
Table 17 – CO
2
Sensor Standard Settings Economizer Input/Output Logic
INPUTS
OUTPUTS
DEMAND
CONTROL
VENTILATION
(DCV)
ENTHALPY
Y1
Y2
COMPRESSOR
N TERMINAL
OUTDOOR
RETURN
STAGE
1
STAGE
2
OCCUPIED
UNOCCUPIED
DAMPER
Below set (DCV
LED Off)
High (Free Cooling
LED off)
Low
On
On
On
On
Minimum position
Closed
On
Off
On
Off
Off
Off
Off
Off
Low (Free Cooling
LED on)
High
On
On
On
Off
Modulating** (between min.
position and full---open)
Modulating** (between closed
and full---open)
On
Off
Off
Off
Off
Off
Off
Off
Minimum position
Closed
Above set (DCV
LED On)
High (Free Cooling
LED off)
Low
On
On
On
On
Modulating{{ (between
min. position and DCV
maximum)
Modulating{{ (between closed
and DCV maximum)
On
Off
On
Off
Off
Off
Off
Off
Low (Free Cooling
LED on)
High
On
On
On
Off
Modulating***
Modulating{{{
On
Off
Off
Off
Off
Off
Off
Off
* For single enthalpy control, the module compares outdoor enthalpy to the ABCD set point.
{
Power at N terminal determines Occupied/Unoccupied setting: 24 vac (Occupied), now power (Unoccupied).
**Modulating is based on the supply--- air sensor signal.
{{
Modulation is based on the DCV signal.
***Modulation is based on the greater of DCV and supply--- air sensor signals, between minimum position and either maximum position (DCV) or fully open (supply--- air signal).
{{{
Modulating is based on the greater of DCV and supply--- air sensor signals, between closed and wither maximum position (DCV) or fully open (supply--- air signal).
OPERATION
Sequence of Operation—When free cooling is not available, the
compressor will be controlled by the thermostat. When free cooling
is available, the outdoor--air damper is modulated by the Economizer
control to provide a 50_ to 55_F (10_ to 12.8_C) supply--air
temperature into the zone. As the supply--air temperature fluctuates
above 55_ (12.8_C) or below 50_F (10_C), the dampers will be
modulated (open or close) to bring the supply--air temperature back
within the set points. For Economizer operation, there must be a
thermostat call for the fan (G). This will move the damper to its
minimum position during the occupied mode.
NOTE: The DCV Max potentiometer must be closed (CCW)
when not using CO
2
sensor.
Above 50_F (10_C) supply--air temperature, the dampers will
modulate from 100% open to the minimum open position. From
50_F to 45_F (10_ to 7.2_C) supply--air temperature, the dampers
will maintain at the minimum open position. Below 45_F (7.2_C),
the dampers will be completely shut. As the supply--air temperature
rises, the dampers will come back open to the minimum open
position once the supply--air temperature rises to 48_F (8.9_C). If
power exhaust is installed, as the outdoor--air damper opens and
closes, the power exhaust fans will be energized and deenergized.
If field--installed accessory CO
2
sensors are connected to the
Economizer control, a demand controlled ventilation strategy will
begin to operate. As the CO
2
level in the zone increases above the
CO
2
set point, the minimum position of the damper will be
increased proportionally. As the CO
2
level decreases because of the
increase in fresh air, the outdoor--air damper will be proportionally
closed. Damper position will follow the higher demand condition
from DCV mode or free cooling mode. Damper movement from
full closed to full open (or vice versa) will take between 1 1/2 and
2 1/2 minutes. If free cooling can be used as determined from the
appropriate changeover command (dry bulb, enthalpy curve, or
differential enthalpy), a call for cooling (Y1 closes at the
thermostat) will cause the control to modulate the dampers open to
maintain the supply air temperature set point at 50_ to 55_F (10_
to 12.8_C). As the supply air temperature drops below the set point
range of 50_ to 55_F (10_ to 12.8_C), the control will modulate
the outdoor--air dampers closed to maintain the proper supply--air
temperature.
607C
--
--
A