Greenheck Microprocessor Controller (475595 IOM) TAP v2.10 April 2014 (RVE, ERCH-01, ERT-01) - Manual (Page 21)

T
HIS SCREEN DISPLAYS THE OUTDOOR AIR DAMPER SET POINT
.
This screen only appears if equipped with a modulating outdoor air and
recirculating damper.
The set point is the proportional percentage of the outdoor air damper being
open.
0% = Full recirculation air
100% = Full outdoor air
Minimum Position – When in the occupied mode, the Active set point will be equal
to a local minimum OA set point, which may be constant or reset by fan speed
if equipped with a modulating supply fan. The OA damper set point can then
be further adjusted between the minimum OA and maximum OA settings with
sequences such as DCV CO2, Building Pressure and Economizer.
Maximum Position – Each sequence that can adjust the OA damper set point
contains a maximum position to prevent excess OA. The Active set point will be
determined based on the greatest demand of the configured sequences. For
example, if a unit is equipped with a DCV CO2 and an economizer sequence,
the OA damper set point will react to an economizer demand even if the CO2 set
point is satisfied. Likewise, if economizer is not available but CO2 is above set
point, the OA damper will open to satisfy the CO2 set point.
Economizer – The Active set point will be reset based on Economizer demand,
between the minimum and maximum positions.
Possible Set Point Sources:
Local – The minimum outdoor air percentage is constant, set by the controller.
SF Reset – The min and max positions are reset by the supply fan speed.
BMS – The BMS can directly control the OA damper position up to the Max BMS
position.
Building Pressure – Damper position is reset by a building pressure control loop.
DCV CO2 – Damper position is reset by a demand-controlled ventilation control
loop based on room CO2 levels.
OA Damper Set Point
Active: 40%
Source: Local 40%
Max Econ: 100%
Supply Fan Speed %
0% (Min Speed) 100% (Max Speed)
OA
Da
m
p
er
Po
si
Ɵ
on O
p
en
%
50%
100%
0%
Min OA
Max Econ
Supply Fan Reset of OA Damper PosiƟon
Max CO2
OA Damper Set Point
Active: 50%
Source: SF RESET
SupplyFan: 0% 100%
Min OA:
50% 40%
Max Econ: 100%
OA Damper Set Point
Active: 30%
Source: DCV CO2
SupplyFan: 0% 100%
Min OA:
30% 20%
Max CO2: 50% 40%
Max Econ: 100%
OA Damper Set Point
Active: 25%
Source: BMS 25%
Max BMS: 50%
Max Econ: 100%
21 DDC Controller for Tempered Air Products
®