Service Instructions; General; Motor And Fan Wheel Assembly - L.B. White AW250 Owner's Manual And Instructions

WARNING
Burn Hazard
■
Heater surfaces are hot for a period of time after the
heater has been shut down.
■
Allow the heater to cool before performing service,
maintenance, or cleaning.
■
Failure to follow this warning will result in burns
causing injury.
WARNING
Fire and Explosion Hazard
■
Do not disassemble or attempt to repair any heater
components or gas train components.
■
All component parts must be replaced if defects are
found.
■
Failure to follow this warning will result in fire or
explosions, causing property damage, injury, or death.
1. Close the fuel supply valve to the heater and
disconnect the electrical supply before servicing
unless necessary for your service procedure.
2. Open side panels for access to heater components.
3 Disconnect the appropriate electrical leads for the
component being replaced.
1. Remove the screws securing the motor mounting
plate to the fan housing.
2. Pull the fan and motor assembly from the housing.
3. Loosen the square head set screw(s) on the fan
wheel with a wrench.
4. Pull the fan wheel from the motor shaft. Use a wheel
puller if necessary.
5 Remove the four (4) nuts securing the motor to the
mounting plate.

Service Instructions

4. The thermostat, and high limt switch can be tested by
jumpering the suspect part out of the electrical
circuit.:
-- Reconnect the electrical supply and open fuel
supply valves.
-- If the heater lights, the component is defective
and must be replaced.
-- Do not operate the heater with the component
jumpered. Replace the part immediately.
-- An alternate method for checking the
components is to perform a continuity check.
5. Do not jumper the air proving switch. If jumpered, the
ignition control will not allow heater operation. Test
the air proving switch for continuity. If defective,
replace the switch
6. For reassembly, reverse the respective service
procedure. Ensure gas connections are tightened
securely.
7. After servicing, start the heater to ensure proper
operation. Check for gas leaks with approved leak
detectors.
8. Clean the heater's orifice with compressed air or a
soft, dry rag. Do not use files, drills, broaches, etc. to
clean the orifice. Doing so may enlarge the hole,
causing combustion or ignition problems. Replace
the orifice if it cannot be cleaned properly.

MOTOR AND FAN WHEEL ASSEMBLY

-- Fan wheel to motor mount plate spacing must
be adjusted to proper clearance before
tightening the fan wheel to the motor shaft.
-- Make sure that set screw(s) of the fan are on
the "flats" of motor shaft when tightening.
Clearance
FIG. 7
MOTOR MOUNT PLATE
MOTOR

GENERAL

3.2 mm
FAN WHEEL
CLEARANCE
13