L.B. White AD250 - Manual (Page 16)

1. The igniter and sensor assembly is located within a
metal enclosure mounted to the heat chamber above
the burner.
2. The igniter/sensor is serviced by removing the screw
that secures the assembly to the heat chamber.and
disconnect the its leads from the ignition control. Lift
the assembly from its mounting slots. See Fig. 13.
3. Reconnect the heater to its electrical supply. Open
the fuel supply valves to the heater.
■
The igniter/sensor assembly may require cleaning due
to accumulations of dust and dirt over a period of time,
thereby affecting its ability to ignite fuel gas and sense
burner flame. Cleaning will require igniter/sensor
removal.
-- If spark appears to be weak, briskly rub the igniter
electrode with emery cloth or steel wool to remove
any buildup. Recycle the heater.
--- If the spark appears strong but the heater cycles off,
briskly rub the sensor rod with emery cloth or steel
wool to remove any build-up. Restart the heater.
■
Ensure the igniter gap is 1/8 -3/16 in. and the igniter
tip is positioned over the burner port according to the
illustration below. See Fig. 13.
16
SENSOR IGNITER
4 MM
HEAT CHAMBER FACE
BURNER
IGNITER LEAD
SENSOR LEAD
IGNITER / SENSOR
ENCLOSURE
TO REMOVE IGNITER / SENSOR WITH ENCLOSURE
REMOVE SCREW, LIFT ASSEMBLY
FROM ITS MOUNTING SLOTS
TO GAP IGNITER LOOSEN SCREW.
MOVE ENCLOSURE UP OR DOWN
TO ALLOW PROPER POSITIONING
OF IGNITER TO BURNER.
FIG. 13
IGNITER AND FLAME SENSOR
AIR PROVING SWITCH WITH PADDLE
NUTS
SWITCH W/PADDLE
PADDLE
OBLONG HOLE
LEADS
HOUSING SIDE
PANEL
1. Open the case access panel on the control box end of
the heater.
2. Remove the two (2) sheet metal screws holding the
switch with bracket to blower housing. Remove the
assembly by turning the switch assembly 90°so the
paddle on the switch arm can be pulled through the
oblong hole on side of fan housing.
3. Disconnect the leads from the air proving switch.
FIG. 12