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When demand ventilation control is not being used, the minimum
position potentiometer should beused tosetthe occupied ventilation
position. The maxim um demand ventilation position should be
turned fully clockw ise. Ad just the min imum position potentiometer
to allow the minimum amount of outdoor air, as required by local
codes, to enter the building. Make mini mum position adjustments
with at least 10 _F (12.2_C) temperature difference betw een the
outdoor and return --air temperatures. To determine the minimum
position setting, perform the following procedure:
1. Calculate the appropriate mixed air temperature using the
following form ula:
(T
o
x OA/100) + (T
R
x RA/100) = T
M
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 (15.6_C), and return--air temperature is 75 _F
(23.9_C). (60 x .10) + (75 x .90) = 73.5_F (23.1_C)
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 positioning is being
used, make sure that the terminals are w ired according to
Fig. 45 and that the mini mum position potentiometer is
turned fully clockw ise.
4. Connect 24 vac across terminals TR and TR1.
5. Ca refully adjust the minimum position potentiom eter until
the measu red mixed--air temperature matches the calculated
value.
6. Reconnect the supply air sensor to terminals T and T1.
Remote control of the Economizer damper is desirable when
requi ring additio nal temporary ventilation. If a field--supplied
remote potentiometer (Honeywell part number S963B1128) is
wired to the Economizer controller, the minimum position of the
damper can be controlled from a remote location. To control the
minimum damper position remot ely, remove the factor y installed
jumper on the P and P1 terminals on the Economizer controller.
Wire the field--supplied potentiometer to the P and P1 terminals on
the Economizer controller. See Fig. 44 and Fig. 45.
607C-- --A