Reznor RPB Unit Installation Manual - Manual (Page 14)

Form I-RPB, P/N 131782 R11, Page 14
6.3 Unit Inlet Air (cont'd) 6.0 Mechanical
(cont'd) 6.3.3 Optional Dampers and Controls (See Wiring Diagram on unit.)
NOTE: Damper controls are illustrated in
FIGURE 12A and 12B. These illustrations are intended to show location only of various air control accessories
and do not represent suggested combinations of accessories.
Furnace
Section Blower
Blower Cabinet
30% Outside
Air Damper
30% Outside
Air Hood
Damper Motor
Return Air
FIGURE 12A - Location of Controls for
30% Outside Air Hood and Damper
Options (AR6 or AR7)
7 8
1 2 3 4 5 6
FIGURE 12B - Control
Locations for 100%
Outside Air and 100%
Return Air Damper
Options
1 Damper Motor
2 Return Air Damper
3 Potentiometer
4 Potentiometer
5 Mixed Air Controller
6 Warmup Control
7 Outside Air Damper
8 Damper Motor
Transformer
Damper Linkage - When units are equipped with
dampers, the dampers are closed during shipment. When
there are both return air and outside air dampers, the
return damper linkage must be adjusted prior to use.
1. Loosen the set screw on the return air damper rod at
the damper arm.
2. Manually open the return air dampers. While the
dampers are opening, the damper rod and arm will
automatically move to their correct positions.
3. Tighten the set screw.
Outside Air
Damper
CLOSED
Return Air
Damper OPEN
Rod for Outside
Air Damper
Setscrew
Outside Air
Damper Arm
Return
Air
Damper
Arm
Rod for Return
Air Damper
Damper
Motor
FIGURE 12C - Example of Outside Air and Return Air
Damper Linkage
Pressure Null Switch
(Used to control
Outside Air Dampers in
Inlet Air Option AR23)
The pressure null switch used in Option AR23 is a Dwyer #1640-0 with a range of .01-
.20" w.c. It is shipped separately for field installation. Refer to the following paragraphs
and the manufacturer's installation instructions included with the switch.
Description and Application - The pressure null switch is a diaphragm operated dif-
ferential pressure switch used in makeup air applications to control building pressure.
It maintains a selected positive or negative pressure setpoint by changing the amount
of outside air being introduced to the building through the modulating outside air damp-
ers. As more pressure is required in the building, the pressure null switch activates the
damper motor driving the outside air damper towards the full open position and the
recirculated air damper towards the closed position. Conversely, as less pressure is
required, the switch drives the dampers in the opposite direction.
1. Select an indoor location free from excessive vibration where oil or water will not
drip onto the switch and where ambient temperature will be within a range of -30°F
(dry air) to 110°F.
2. Mount the switch with the diaphragm in a vertical plane. The switch is posi-
tion sensitive and is calibrated to operate properly when the diaphragm is vertical.
Mount switch securely.
3. Connect the pressure taps on the top of the switch to sources of air pressure differ-
ential. Metal tubing with 1/4" O.D. is recommended, but any tubing system which
will not unduly restrict the air flow may be used. To maintain a positive building
pressure, vent the low pressure tap to the outdoors and allow the high pressure
tap to monitor building pressure. To maintain a negative building pressure, reverse
the functions of the high and low pressure taps. In either case, be sure that the
outdoor vent is protected from the wind and screened from insects.
4. Adjustment of the Switch - The "HIGH" actuation point of the null switch is indi-
cated on a calibrated scale secured to the transparent range screw enclosure.
Installation Instructions
for Pressure Null
Switch (FIGURE 13)