MicroMetl ECD-SRT SA Series - Performance Data

10
Performance Data — Refer to Fig. 18 for barometric relief
capacity. Refer to Fig. 19 for return air pressure drop.
Fig. 18 - Barometric Relief Flow Capacity
Fig. 19 - Return Air Pressure Drop
If a eld-installed accessory CO2 sensor is connected to the economizer
control, a demand controlled ventilation strategy will begin to operate
in parallel with the free cooling strategy. As the CO2 level in the
zone increases above the CO2 set point position (as controlled by the
DCV set potentiometer), the position of the damper will be increased
proportionally to the DCV Max position (as controlled by the DCV Max
potentiometer). As the CO2 level decreases because of the increase in
fresh air, the outdoor-air damper will be proportionally closed back down
to the minimum open position. Damper position will follow the higher
demand condition from the DCV mode or free cooling mode.
a
For single enthalpy control, the module compares outdoor enthalpy to the ABCD set point.
b
Power at N terminal determines Occupied/Unoccupied setting:
• W7212: 24 vac (Occupied), no power (Unoccupied).
c
Modulating is based on the supply-air temperature sensor signal.
d
Modulation is based on the DCV signal. If the CO2 sensor input (AQ-AQ1) terminals is < 1Vdc or
the sensor has failed, the motor will drive to MIN POS or DCV MAX which ever is highest.
e
Modulation is based on the greater of DCV and mixed air sensor signals, between minimum
position and either maximum position (DCV) or fully open (mixed air signal).
INPUTS OUTPUTS
Demand Control
Ventilation (DCV)
Enthalpy
a
Y1 Y2
Compressor N Terminal
b
Outdoor Return
Stage
1
Stage
2
Occupied
b
Unoccupied
b
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
c
(between min.
position and full-open)
Modulating
c
(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
d
(between min.
position and DCV maximum)††
Modulating
d,g
(between
closed and DCV
maximum)††
On Off On Off
Off Off Off Off
Low
(Free Cooling LED On)
High On On On Off Modulating
e
Modulating
f
On Off Off Off
Off Off Off Off
Table 6 - Economizer Input/Output Logic
f
Modulating is based on the greater of DCV and mixed air sensor signals, between closed and
either maximum position (DCV) or fully open (mixed air signal).
g
Modulation is based on the DCV signal, if the CO2 sensor input (AQ-AQ1) terminals is < 1Vdc or
the sensor has failed, the motor will drive DCV MAX in occupied mode. When power is cut to the
economizer (fan is off) then the damper will spring return closed.
0
500
1000
1500
2000
2500
00.050.1 0.15 0.20.250.3
RELIEF FLOW (CFM)
RETURN DUCT STATIC PRESSURE (in. wg)
ECD-SRT12SA
ECD-SRT34SA and
ECD-SRT05SA
0
1000
2000
3000
4000
5000
6000
00.1 0.20.3 0.4
RETURN AIR FLOW (CFM)
RETURN DUCT STATIC PRESSURE DROP (in. wg)
ECD-SRT12SA
ECD-SRT34SA
ECD-SRT05SA