Do not attempt to disassembly or repair
fuel control valve unless facilities are
available to conduct the flow test
described in paragraph 3-36b(1)(h). An
improperly calibrated valve can cause ex-
cessive fuel to build up in and around the
heater assembly, creating a fire hazard.
a. Remove mounting bracket (2) by
removing four screws (1) that secure it to the valve
b. Remove three screws (3) and remove
the outer plate (4), insulator plate (5), preformed
packing (6), 3-hole plate (7), and restriction orifice
plate (8). Pull three small preformed packings (9) out
of recesses in valve body.
Handle the orifice plate with care. Do not
drop it. Do not force any object through
the orifice plate openings. The slightest
distortion in the plate or orifices will in-
terfere with proper operation of the fuel
c. Remove adjusting screw (21) and
spring (22). Remove four screws (20) and remove
diaphragm cap (23), diaphragm assembly (24) and
preformed packing (25). Unscrew valve core (19) and
d. Remove restriction solenoid and valve
assembly by removing screw (32). Pull out coil
assembly (31) and washer (30). Remove three screws
(33) in bottom of solenoid cup (29). Remove solenoid
cup and pull out sleeve and core assembly (28),
gasket (27), valve spring (26), and plunger assembly
(34). Remove valve seal (36) from bottom of plunger
e. Repeat d above to disassemble shut-off
solenoid and valve assembly, except pull out coil
assembly (10) instead of coil assembly (31).
f. Remove bleed valve stem (37) and inlet
screen (38) and valve body (18).
g. To remove thermostat, unsolder wire
(14) from the electrical terminal on the valve body.
Slide off the insulating sleeve (13) and the insulator
(12). Remove two screws (15) that secure the ther-
mostat (17) to valve body, and remove the ther-
mostat. If the thermostat is being replaced, un-
solder the cable assembly (16) from terminal on ther-
h. Unscrew elbow (11) to remove it from
valve body (18).
(7) Ignition control (fig. 3-10.2).
(a) Loosen the two Dzus fasteners which
secure the guard assembly (16) to the top of the
heater; remove the guard.
(b) Cut the two cable assembly straps (37)
which bundle the wires together. Disconnect the
igniter lead and the voltage limiter lead from one
end of the ignition control (25). If necessary to
provide access to the wires, remove the fuel control
valve ((6)(b) above).
(c) Disconnect the ignition control lead from
one of the NO contacts on the flame detector switch
(21). Remove the two screws (17) on the outer edge of
the ignition control, and loosen the two remaining
screws. Pull off the ignition control.
(8) Burner assembly (fig. 3-2).
(a) Remove blower assembly ((1) above).
(b) Loosen the two fasteners which secure the
electrical inlet assembly (36) to the heater housing
(28), and swing it out of the way.
(c) Remove the igniter (9) as described in (3)
above. Remove the seal (35) from the top of the
(d) Remove the screw (4) which secures the
igniter tube and bracket (8) to the secondary blower
housing (3) and pull out the tube to remove it.
(e) Disconnect fuel tube (5) by loosening com-
pression nuts (6) at fuel control valve (26) and at bur-
ner (10); pull out tube.
(f) Slide secondary blower housing (3) out of
heat exchanger assembly (15).
(g) Remove six screws (39) that secure the
burner (10) to heat exchanger, and pull out burner.
(h) Refer to figure 3-10.5 and disassemble the
burner as follows:
Legend for fig. 3-10.5:
Plate and bushing assembly
Fuel vaporizer shield
Burner cup and stud assembly