Thomas & Betts LDAP 1200 - Manual (Page 36)

Form RZ-NA-I-LDAP, P/N 207733 (Rev 2), Page 36
34. Main Venter Motor and Wheel (Models 800 and 1200 only)
The main venter motor and wheel is located on the top of the first heat section of a
Model LDAP 800 and 1200. The vent system attaches to the collar on the top of the
main venter housing.
Remove dirt and grease from the motor casing, the venter housing, and the venter
wheel. Venter motor bearings are permanently lubricated.
Follow the instructions in Paragraph 33 for replacement of the venter motor and wheel
assembly. Keep all hardware removed to be used in re-assembling and installing the
replacement parts. See FIGURE 27 for venter wheel and motor spacing.
35. Fan Motor(s),
Fan Blades,
and Guard(s)
FIGURE 28- Fan Blade
Position on the Shaft
3”
(76mm)
Fan
Motor
Fan
Blade
Main Venter
Motor
Motor Wire
and Cable Assy
Screw
Flat Washer
Hex Nut
Exhauster Motor Base Assy
Wheel
1-1/4” (32mm)
Main Combustion
Air Pressure
Switch
Venter Housing
Venter
Motor
FIGURE 27- Venter Motor
and Wheel Spacing on
Main Venter (Size 800 and
1200)
33. Heat Section
Venter Motor
and Wheel
(cont’d)
Replacement Instructions
7/16” (11mm) inside
FIGURE 26 - Venter Wheel
Position on Shaft - applies
to all heat section venter
assemblies
Remove dirt and grease from each motor, 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.
Repeat the procedure for each heater section.
1. If the heater is installed, turn off the gas and disconnect the electric power.
2. Open the access door and disconnect the fan motor wires, capacitor wires at the
capacitor, and ground screw.
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.
Be sure the fan blade is in the proper position on the shaft; refer to the illustration
in FIGURE 28.
Position the assembly on the heater. Attach the fan guard.
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.
1. Turn off the gas and disconnect the electric power.
2. Open the burner/control compartment access panel.
3. Disconnect the three venter motor wires at the DSI control, capacitor wires at
the capacitor, and ground screw (located on the control panel).
4. Holding the venter motor, remove the six screws that attach the venter motor
mounting plate to the venter housing. Remove the motor and wheel assembly
from the heater.
5. Re-assemble with the replacement venter motor and
wheel assembly. See FIGURE 26.
6. Follow the wiring diagram to connect the venter wires.
7. Replace the access panel. Restore power to the heater
and turn on the gas. Light, following the instructions on
the lighting instruction plate. Check for proper opera-
tion.