Installation manual

McQuay IM 487-4 87
Unit Options
Variable Frequency Drive Operation
Refer to the vendor instructions supplied with the unit.
Convenience Receptacle/Section Lights
A Ground Fault Circuit Interrupter (GFCI) convenience
receptacle is provided in the main control box on all units. To
use this receptacle, connect a separate field-supplied 115V
power wiring circuit to the 115V field terminal block TB7,
located in the main control box.
Optional lights are available for certain sections in the unit.
Each light includes a switch and convenience receptacle and is
powered by the external 115V power supply connected to
TB7.
DesignFlow™ Outdoor Air Damper Option
DesignFlow™ airflow measurement stations are located inside
the louvered outdoor air intake doors between the intake
louver and outside air dampers. Essentially, they consist of a
vane that is repositioned by airflow, the amount of rotation
indicating the amount of airflow. They are calibrated precisely
at the factory and no further calibration is required. However, a
leveling adjustment is required in the field so that the
DesignFlow unit is in the same orientation as when it was
factory calibrated. See “DesignFlow Station Startup” below.
The rotational position of the DesignFlow unit vane is
translated into CFM by the microprocessor in the MicroTech II
control system. The position of the vane is determined by two
things—the force of the airflow impacting the vane and the
gravitational effect on the vane. Gravity is the only factor at
the lower CFM end of the range. On a correctly leveled unit,
this gravitational effect will be the same as when the unit was
calibrated in the factory.
Accurately leveling a station involves applying a precise
mechanical force against the vane. This force should cause the
vane to move to a specific position if the DesignFlow unit is
correctly leveled.
DesignFlow Station Startup
• Before initial startup of the rooftop unit, carry out the
following procedure on both the right-hand (control panel
side) and left-hand (side opposite the control panel)
DesignFlow station vanes (see Figure 95).
Note: This procedure is much easier to carry out with two
people—one making the mechanical adjustments and
the other viewing and recording readings on the
MicroTech II control panel.
1 Verify that power is supplied to the unit’s MicroTech II
control system. The DesignFlow startup procedure cannot
be completed without use of the MicroTech II controls.
2 Unlock and open the louvered outdoor air intake door on
the side of the unit (see Figure 95).
3 The swinging vane on the measurement station is locked in
place for shipment. Unlock it by removing the two shipping
screws. One is located one inch from the top of the vane
and the other one inch from the bottom of the vane. Both
are about eight inches in from the outer edge of the vane.
4 Examine the station for shipping damage. Manually rotate
the vane and verify that it does not rub against anything.
Figure 95. DesignFlow station
5
Manually hold the vane closed against the mechanical stop
at the top of the assembly. Then, read the current vane
leveling position on the MicroTech II keypad/display.
Do this by viewing the LH Lvl Pos= or RH Lvl Pos=
parameter in the DesignFlow setup menu. The LH Lvl
Pos= parameter indicates the current position of the vane
for the left-hand DesignFlow station (side opposite the
control panel). The RH Lvl Pos= parameter indicates the
current position of the vane for the right-hand DesignFlow
station (control panel side).
Important: Wait several seconds until the value on the
keypad stabilizes before taking the reading.
For detailed information regarding operation and
navigation through the unit keypad, refer to Operation
manual OM 137 (discharge air control units) or OM 138
(zone control units).
6 Confirm the value of the reading. Ideally, it should read
close to 20.00 (19.50 to 20.50 is acceptable). If the reading
is out of range, loosen the screws fixing the mechanical
stop at the top of the assembly, make a small adjustment,
and recheck until the reading is in the specified range.
Note: Generally, adjustments should not be necessary.
7 Locate the leveling component kit, which is shipped with
the unit, in the unit mail control panel.
8 Duct tape the fulcrum alignment plate to the bottom corner
of the vane (see Figure 96) aligning it as follows:
a The bottom edge of its notches should be flush with the
bottom edge of the vane.
b The side of one notch should be even with the bend near
the outer edge of the vane.
c The plate should be flat against the outer surface of the
vane.