035-18895-000-A-0902
6
Unitary Products Group
These heaters are located within the central compartment of
the unit with the heater elements extending into the supply air
chamber. Refer to Figure 7 for access panel location.
Fuses are supplied, where required, by the factory. Some KW
sizes require fuses and others do not. Refer to Table 2 for
minimum air flow limitations and to Table 8 for electrical data.
OPTIONAL ECONOMIZER / MOTORIZED DAMPER
RAIN HOOD
The instructions for the optional economizer /
motorized
damper rain hood can be found in form 44-320-2. The
procedures listed in those instructions should be used when
field assembling an economizer rain hood onto a unit. The
outdoor and return air dampers, the damper actuator, the
damper linkage, the outdoor and return air divider baffles, and
all the control sensors are factory mounted as part of the
“factory installed” economizer option.
ENTHALPY SETPOINT ADJUSTMENT
Remove the economizer access panel from the unit to check
the following adjustments. Loosen but do not remove the two
panel latches.
CAUTION: Extreme care must be exercised in turning both the
setpoint and minimum position adjusting screws to
prevent twisting them off.
1. The enthapy set point for the dampers may now be set by
selecting the desired setpoint shown in Figure 6. Adjust as
follows:
•
For single enthalpy operation, carefully turn the setpoint
adjusting screw to the “A”, “B”, “C” or “D” setting corre-
sponding to the lettered curve.
•
For dual enthapy operation, carefully turn the setpoint
adjusting screw fully clockwise past the “D” setting.
2. To check that the damper blades move smoothly without
binding, carefully turn the minimum postion adjusting screw
fully clockwise and then energize and de-energize termi-
nals “R” to “G”. With terminals “R” to “G” energized, turn the
minimum position screw counterclockwise until the desired
minimum position has been attained.
3. Replace the economizer access panel. Reposition the two
latches horizontally and retighten the screws.
