and remove slotted plate (19) from inside the
(4) Remove fuel pump by removing at-
heater housing,
taching hardware.
(3) Disconnect the ground strap and the
b. lnspection. Inspect the fuel pump for any
electrical lead of the preheat resistor (16)
indication of visual damage. Inspect filter for
from terminal number 7 of the terminal board
cleanliness.
(20).
c. Cleaning. Clean the fuel pump with a
(4) Remove the compression nut (7) at
solvent-dampened cloth.
the lower end of the standpipe (8) and lift
d. Installation. Install the fuel pump by re-
out standpipe, preheater resistor (16) and
versing the removal procedures.
flange (18) through opening in the heater
housing (27).
3-46. Igniter Assembly
b. Installation. install the preheater resistor
by reversing the removal procedure.
(1) Remove cover (10) by loosening nuts
(11), and turning cover in a counterclockwise
348. Flame Detector Switch
direction.
(2) Disconnect ground lead (12) by re-
( 1 ) Remove blower assembly (21) by
moving nut (13) and lockwasher (14) from
loosening nuts (22) and turning blower in a
inside the heater housing (27) and bend ig-
clockwise direction.
niter ground wire so that it will fit inside a
( 2 ) Disconnect electrical leads from
deep socket.
blower (21) to terminal block (20).
(3) Disconnect the connecting strap of
(3) Disconnect electrical leads from flame
the preheat resistor (16) and remove igniter
detector switch (23) to terminal block (20).
(15).
(4) Loosen compression nut which at-
b. Inspection. Inspect the igniter for excess
taches switch (23) to heater burner (24).
deposit of carbon.
Pull the switch wires through the grommet
c. Cleaning. Clean the carbon from the ig-
(25) in the heaterhcusing, then pull the switch
niter with a sharp tool.
straight out of the heater burner, being care-
d. Repair. Replace the igniter if it cannot
ful not to bend the steel tube.
be repaired.
Caution: This tube contains a quartz
rod which may be broken by excessive bending
ing the removal procedures.
of the tube.
b. Adjustment.
3-47. Preheater Resistor
(1) Loosen switch mounting nuts.
(1) Remove cover (10) by loosening nuts
(2) Rack off the adjusting screw until
(11) and turning cover in a counterclockwise
the switch clicks.
direction.
(3) Slowly turn the adjusting screw in
(2) Remove the screws (17) from the
until the microswitch clicks.
flange (18) which surrounds the standpipe
(8). Leave one plate loose on the standpipe
past the click point.
Plate
19
10 Cover
1
Valve
Terminal board
20
11 Nut
2
Hose
Blower assembly
12 Ground lead
3
Air hose
22
Nut
1 3 Nut
4
Clamp
23
Flame detector switch
14 Lockwasher
5
Clamp
Heater burner assembly
24
15 Igniter
6
Fuel solenoid valve
Grommet
25
16 Preheat resistor
7
Compression nut
26
Screw
17 Screw
8
Standpipe
27
Heater housing
18 Flange
9
Fuel pump
Figure 3-28.-Continued
56
