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Reznor B Unit Installation Manual User Manual

Page 37

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Form I-F/B, P/N 98126 R21, Page 37

FIGURE 47 -

Proper

Position

of the Fan

Blade on the

Motor Shaft

Fan Motor

A

Fan

Hub

Model Size Electrical Supply Set Screw Torque In-Lbs "A" Hub to Motor

25

60 Hz

80 + or - 10

1-1/4" (32mm)

50

60 Hz

80 + or - 10

3/8" (9.5mm)

75

60 Hz

80 + or - 10

1/8" (3.2mm)

25,50,75

50 Hz

80 + or - 10

3-1/4" (82.6mm)

100-125

50 or 60 Hz

120 + or - 10

2-1/2" (63.5mm)

165-400

50 or 60 Hz

150 + or - 10

2-1/2" (63.5mm)

1. If the heater is installed, turn off the gas and disconnect the electric power.

2. Remove the left outer side panel (left when facing the rear of the unit). Disconnect

the fan motor wires.

3. Depending on the date that the heater was manufactured, it will have either a

lower-half fan guard only, two-piece full fan guard, or a one-piece full fan guard. If the

unit has a two piece fan guard, remove the tension mounted upper half fan guard and

the four screws that hold the lower half. If the unit has a one-piece fan guard, remove

all of the screws that retain the fan guard. 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 hardware 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 grounding for the

motor.
Be sure the fan blade is in proper position on the shaft. Position the fan as shown in

FIGURE 47 according to the chart.

Position the assembly on the heater. Attach the fan guard at the center mounts.

(

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 adequate clearance. Repeat this procedure

until the assembly is positioned properly.

5. If necessary, drill the required upper and lower fan guard mounting holes. Attach

the fan guard at all upper and lower mounting points using either the screws removed

or field-installed sheetmetal screws.

6. Reconnect the fan motor wires and replace the outer side panel.

7. Restore power to the heater and turn on the gas. Light, following the instructions

on the lighting instruction plate. Check for proper operation.

10.2.8 Vent System

Check the vent system at least once a year. Inspection should include all joints, seams,

and the vent cap. Replace any defective parts.

10.2.9 Blocked Vent

Switch

The manual reset blocked vent switch is located on the front top of the drafthood. The

sensor is located near the relief opening of the drafthood.

Blocked Vent Switch

Model

Size

Single-Stage Gas Controls

Two-Stage Gas Controls

Temperature Setting

P/N

Temperature Setting

P/N

25

200°F

112751

N/A

N/A

50

225°F

112752

N/A

N/A

100-400

275°F

121275

225°F

112752

10.2.10 Fan, Limit, &

ECO Controls

If it is determined that the fan or limit controls or the ECO device needs replacing, use

only factory-authorized replacement parts that are designed for your heater. See loca-

tions in

FIGURE 48.

WARNING: An ECO circuit interruption is a major failure caused by

a malfunction of the primary safety controls or mis-wiring, and will

require correction of the cause of the failure and the replacement

of the fan and limit controls and wiring before the heater can be

returned to service. See Hazard Levels, page 2.

NOTE: ECO control is not

on any units manufactured

after 8/2008. All units with

match-lit pilot have an ECO

device. Units with spark

pilot manufactured prior to

8/99 have an ECO device.

Fan Models: Follow these

instructions for replacement

of the fan guard, fan motor

or fan blades.

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