Reznor FT Unit Installation Manual - Manual (Page 18)

Form RZ-NA-I-FT, Mfg No. 173473 Rev 8, Page 17
Figure 14 - Proper
Position of the Fan
Blade on the Motor
Shaft
Fan Motor
Fan Hub
A
CAUTION: Eye protection is recommended.
The inner surfaces of the heat exchanger can be reached for cleaning
with the burner and venter assemblies removed (See Figure 12 and
Paragraph 21). Clean with a long furnace brush or a heavy wire to
which steel wool has been attached. Brush inside each heat exchanger
tube until all foreign material is removed. A flashlight is helpful in
examining the inside of the tubes.
26. Fan
Remove dirt and grease from the motor. Remove dirt and grease from
the fan guard and blades. Use care when cleaning the fan blades to
prevent causing misalignment or imbalance. Check that the hub of the
fan blades is secure to the shaft.
Follow these instructions for replacement of the fan guard, fan motor
and/or fan blades.
1. If the heater is installed, turn off the gas and disconnect the electric
power.
2. Remove the access panel or 2x4 junction box cover. Disconnect the
fan motor wires.
3. Remove the assembled parts (the fan guard, the motor and the fan
blade).
4. Disassemble and replace whatever parts are needed and reassemble
using whatever part(s) are being replaced and the original parts. If
the fan guard is being replaced, it is important that the same hard-
ware be used for attaching the motor to the fan guard as was used
with the original guard. These screws are especially made to cut
through the coating on the fan guard to provide adequate ground-
ing for the motor.
Be sure the fan blade is in the proper position on the shaft; refer to
the illustration and table in Figure 14.
Position the assembly on the heater. Attach the fan guard.
(IMPORTANT: If replacing the fan guard, use the screws that held
the original fan guard. These specially designed screws will cut
through the coating on the fan guard to provide a ground for the fan
motor.)
Rotate the fan blade to check for adequate clearance. If adjustment
is required, loosen the mounting screws, re-position the fan guard,
and tighten the screws. Rotate the fan blade and re-check for ad-
equate clearance. Repeat this procedure until the assembly is posi-
tioned properly.
5. Reconnect the fan motor wires and replace the access panel.
6. Restore power to the heater and turn on the gas. Light, following
the instructions on the lighting instruction plate. Check for proper
operation.
Figure 13 - Ignitor
Assembly
Spark Gap Measurement
Excessive dirt buildup on and inside the ports on the burner could
cause fuel gas to spill out of the back of the burner tube. Fuel gas
spilling out of the back of the burner tube will cause gas odor inside
the building, and if not corrected, could eventually cause a fire/explo-
sion hazard. To prevent fuel gas spilling from the back of the burners,
clean the burner ports at least annually. Remove any soot deposits from
the burner with a wire brush. Clean the ports with an aerosol degreaser
and/or compressed air. Wipe the inside of the burner tube clean. (Clean-
ing the burner with an aerosol degreaser is highly recommended as the
degreaser will retard future buildup of dirt.)
Inspect the cleaned burner for any damage or deterioration. If the burner
has any damage or signs of deterioration, replace it.
Re-assemble the heater and test for proper operation.
23. Burner Orifices
Heaters are shipped with orifices of proper size and type for gas and
altitude specified on the order. When ordering replacement orifices,
give BTUH content, specific gravity of gas, and altitude shown on the
rating plate, as well as the model and serial number of the heater.
24. Ignition System
To access the ignition system, follow Steps 1-3 in Paragraph 22.
Ignitor
- Refer to Figure 12 and locate the ignitor (on the side of the
burner rack). Disconnect the wire; remove the screw and the ignitor.
Clean the ignitor assembly with an emery cloth.
Spark gap must be maintained to 1/8". See Figure 13.
IMPORTANT:
When re-assembling, the brown ground wire must re-
main attached to the ignitor.
CAUTION: Due to high voltage on the spark wire
and electrode, do not touch when energized. See
Hazard Levels, page 1.
Flame Sensor -
Refer to Figure 12 and locate the flame sensor. Dis-
connect the wire; remove the screw and the flame sensor. Clean with
an emery cloth.
Ignition Control
- The integrated circuit board monitors the operation
of the heater including ignition. Do not attempt to disassemble the cir-
cuit board. However, each heating season the lead wires should be
checked for insulation deterioration and good connections.
Proper operation of the direct spark ignition system requires a mini-
mum flame signal of 1.0 microamps as measured by a
microampmeter.
For further information and check out procedure on the direct spark
ignition system, refer to the manufacturer's control operating instruc-
tions supplied with the heater.
25. Heat Exchanger
The outside of the tubular heat exchanger can be cleaned from the
front of the heater with an air hose and/or a brush. Remove all accumu-
lated dust and grease deposits.
.74
1.275
7/16
.125 ±.015 Spark Gap
5/32
Model
S ize
S et S crew
Torque
(Inch-Lbs)
"A" Hub to
Motor
30, 45 80 ± 10 1-1/8"(29mm)
60, 75,
100, 125
120 ± 10 2" (51mm)
150, 200 150 ± 10 2" (51mm)
250, 300 150 ± 10 3-1/4"(83mm)