CHAFTER7
Check ignition cables for cracks in the insulation.
Also see that all connections between the
trans-
former and electrodes are tight.
Periodically remove the access plug from the gas
pilot aspirator (Fig. 5-1
0) and clean
out
any
accumulated lint
or
foreign material.
H.
GAS
BURNER
I\IIAINTENANCE
The gas burner components should be inspected
for evidence
of
damage
due
to improperly ad-
justed
combustion.
Combustion
adjustments
should be checked monthly.
See Section T in
Chapter 5.
Check periodically for a proper seal between the
end
of
the burner housing and oven refractory
(see Fig.
7-10). Any deterioration
of
the seal
should be
corrected, as an improper
or
poor
seal
allows air leaks, which
can
cause overheating
or
burning
of
the burner housing.
Whenever the burner
is
removed, the diffuser,
gas housing and gas spuds
(HTB model only)
should
be
checked for any deterioration. Verify
that the diffuser skirt
conionns
to the bore
of
the
butner housing
so
as to minimize the amount
of
combustion air which bypasses the diffuser.
If
the burner is an HTB model,
check
to see that the
diffuser is properly located in reference to the gas
spuds. There should be 1/4" between the edge
of
the diffuser fins and the gas spuds when the
burner is installed.
Check
to
see
that the diffuser
fins
do
not interfere with the gas ports
or
gas
spuds in the burner housing (see Fig. 5-11).
See
Section V in Chapter 5 for more information.
Check the electrode setting for any cracks that
might be present
on
the porcelain insulator.
Replace the electrode
if
cracking
is
evident, since
cracks
can
cause grounding
of
ignition voltage.
Inspect the tip
of
the electrode for signs
of
pitting,
combustion deposits, and
wear
and dress as re-
quired with a fme file.
See
Fig.
5-l
0 for electrode
settings.
750-150
INSPECI'ION AND MAINTENANCE
Periodically remove the access plug from the gas
pilot aspirator (Fig.
5-10) and clean
out
any
accumulated foreign material.
Check the ignition cables for cracks in the
insula-
tion. Verify that all connections between the
transformer and electrode are tight.
I.
1\nCTORIZED
GAS
VALVE(S)
The
motorized gas valve (hydramotor) operating
mechanism is completely immersed in oil and
little maintenance
is
required, because
of
the
sealed design. However, proper operation should
be
checked
on
a routine periodic basis.
Keep
outer
parts
of
the valve clean, especially the
stem between the operator and the valve. A
nick-
ed, scored
or
otherwise damaged valve stem can
cause leakage.
Do not remove dust covers if
installed.
The
packing gland
'is
of
the
0-ring
type.
If
oil
is
noticed around the operator base,
or
if
leakage
occurs, repair by replacing any leaking
0-rings
and refill the actuator with oil.
If
the actuator is sluggish
or
fails to operate, even
after the oil level
is
checked, replace the entire
operator portion.
J.
SOLENOID
VALVES
Foreign matter between the valve seat and seat
disc can cause leakage. Valves are readily
disas·
sembled; however, care must be used during
disassembly
to be sure that internal parts are not
damaged during removal and that reassembly
is
in proper order.
A low bum
or
buzzing will normally
be
audible
when the coil
is
energized.
If
the valve develops
a loud buzzing
or
a chattering noise,
check
for
proper voltage and clean the plunger assembly
and interior plunger tube thoroughly.
Do
not use
CHAPTER 7-9
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