Reznor EEDU Unit Installation Manual - Manual (Page 18)

Form I-EEDU, Page 18
7.0 Electrical
Supply and
Wiring
7.1 General
All electrical wiring and connections, including electrical grounding MUST be made in
accordance with the National Electric Code ANSI/NFPA No. 70 (latest edition) or, in
Canada, the Canadian Electrical Code, Part I-C.S.A. Standard C22.1. In addition, the
installer should be aware of any local ordinances or gas company requirements that
might apply.
Check the rating plate on the heater for the supply voltage and current requirements.
A separate line voltage supply with fused disconnect switch should be run directly from
the main electrical panel to the furnace, making connection to leads in the junction box.
All external wiring must be within approved conduit and have a minimum temperature
7.2 Supply Voltage
and Wiring
6.0 Mechanical
(cont'd)
6.3 Duct Furnace
Airflow (cont'd)
6.3.5 Discharge Air Sensor for Makeup Air Application (cont'd)
FIGURE 16B -
Discharge Air Sensor
Holder, P/N 115850,
used in Makeup Air
Option AG15
Secure sensor in clip.
Position holder so that it
shields sensor from direct
airflow.
Instructions for Installing Discharge Air Sensor in the Ductwork
1. Depending on the option, the sensor will be as shown in either FIGURE 16B or
16C. See Paragraph 3.2 for a list of shipped-separate components by option.
2. Determine a location in the ductwork to install the sensor.
Select a location a sufficient distance from the outlet to provide a good mixture of
discharge air temperature. According to the latest edition of AMCA Standard 201,
in straight ducts, the air is typically well mixed a minimum of five equivalent duct
diameters from the discharge of the unit with equivalent duct diameter defined
as equal to the square root of 4AB/3.14. "A" and "B" are the duct cross-sectional
dimensions.
Example: Supply ductwork cross-sectional dimension is
24" x 12" (610mm x 305mm).
5 x
4 x 12 x 24
3.14
= 96" 5 x
4 x 305 x 610
3.14 = 2435mm
Solution: Locate the sensor a minimum of 96" (2435mm)
from the outlet of the unit.
NOTE: If the length of the discharge duct is less than 8 ft (2.4M), a mixing vane is
recommended for mixing the discharge air.
Do not mount the sensor in the ductwork after a split in the supply as that will
cause loss of control in the duct that does not house the sensor.
3. The position of the sensor holder or mixing tube is important. The holder in
FIGURE 16B will extend 9-3/16” (233mm) into the ductwork. The mixing tube in
FIGURE 16C is 12" (305mm) long.
In horizontal ductwork, locate the sensor assembly in the top, middle of the duct
with the sensor probe extending vertically down into the center of the airstream.
In vertical ductwork, locate the sensor assembly in the middle of the side of the
duct that corresponds with the top middle of the discharge outlet.
Turn the holder so that the element will be shielded from direct airflow and will
sense the air temperature as it flows through the holes in the holder.
At the selected location in the ductwork, mark the diamond-shaped hole
[approximately 1” x 1” (25mm x 25mm)] required for the sensor holder or the round
hole needed for the mixing tube. Cut the hole no larger than required.
4. Option AG15 - Push the element into the clip in the holder. Determine where the
sensor wire should enter the box and remove the knockout. Slide the holder into
the ductwork. Using four field-supplied No. 6 sheetmetal screws, attach the box
portion of the holder to the ductwork. Attach a field-supplied cable connector to the
box, connect the sensor wire, and attach the box cover.
Options AG8 and AG9 - Slide the mixing tube into the ductwork and attach the
sensor. Connect the wires as shown on the wiring diagram.
FIGURE 16C -
Discharge Air Sensor
and Mixing Tube
used in Electronic
Modulation Options
AG8 and AG9
Options AG15 (2-stage valve with remote ductstat) and Options AG8 and AG9
(electronic modulation with duct sensor) require field installation of the sensor in the
discharge ductwork. Option AG15 uses the box and sensor holder in FIGURE 16B.
Options AG8 and AG9 include a sensor and mixing tube as illustrated in FIGURE 16C.
Follow the instructions below to install the sensor in the ductwork.
For control information, see Paragraph 8.4.