NOTE: Install filters so that “Air Flow” arrows point toward the
unit.
8. Install filter cover over the end of the hood with one screw
(center of hood), securing filters into position.
CAUTION: When proceeding with Steps 9 and 10, extreme
care must be exercised while turning both the set
point and minimum position adjusting screws to
prevent twisting them off.
9. The enthalpy set point for the dampers may now be set by
selecting the desired set point from graph in Figure 7. For
a single enthalpy economizer, carefully turn the set point
adjusting screw to the “A”, “B”, “C” or “D” setting corre-
sponding to the lettered curve. For a dual enthalpy econo-
mizer, carefully turn the set point adjusting screw fully
clockwise past the “D” setting.
10. To check that the damper blades move smoothly without
binding, carefully turn the minimum position adjusting
screw fully clockwise and then energize and de-energize
terminals “R” to “G”. With terminals “R” to “G” energized,
turn the minimum position screw counterclockwise until the
desired minimum position has been attained.
11. Replace the filter section access panel.
FIG. 7 - ENTHALPY SET POINT ADJUSTMENT
EXTERNAL STATIC PRESSURE DROP
DESCRIPTION
RESISTANCE, IWG
CFM
1000
1200
1400
1600
1800
2000
2200
2400
2600
2800
3000
Economizer
1, 2
0.07
0.08
0.09
0.11
0.13
0.15
0.17
0.20
0.23
0.26
0.30
Bottom Duct Connections
1
0.06
0.07
0.08
0.09
0.10
0.11
0.12
0.14
0.16
0.19
0.22
1
Deduct these resistance values from the available external static pressure shown in the respective Blower Performance Table.
2
The pressure thru the economizer is greater for 100% outdoor air than for 100% return air. If the resistance of the return air duct system is less than 0.25 IWG, the unit will deliver less CFM
TABLE 4 - STATIC RESISTANCES
530.18-N8Y
8
Unitary Products Group
