.
CHAPTER
7
any oil. Make sure that the plunger tube and
solenoid are tight when reassembled. Take care
not
to nick, dent
or
damage the plunger tube.
Coils may be replaced without removing the
valve from the line.
!WARNING
Be sure
to
turn
off
power
to
the
valve In order
to
avoid electrical
shock,
which
could
result
In
serious personal Injury
or
death.
Check the coil position and make sure that any
insulating
washers
or
retaining
springs
are
reinstalled in proper order.
·
K. AIR
CONTROL
DAMPER,
UNKAGE
AND
CAM
SPRING
The burner air control damper should be checked
for free movement
as
a part
of
the monthly in-
spection. With the burner
off
and the jackshaft
damper control rod disconnected, the air control
damper should rotate freely through
its
entire
range
of
movement. Any resistance to movement
or
excessive play in the support bearing should
be
investigated and corrected before the burner
is
put back in operation.
The overall tightness
of
the linkage assembly
should be checked monthly.
If
necessary, tighten
the setscrews and the connections at the uniballs.
Check the uniballs for wear and replace
if
neces-
sary.
The linkage assembly should be tight but should
not bind.
If
the linkage assembly
is
binding,
determine the cause
of
the binding and correct as
necessary.
Linkage rod end attachment points should be
marked on the variable displacement linkage
arms
as
an aid
in
subsequent reassembly.
CHAPTER 7-12
INSPEcriON
AND :MAINTENAL'ICE
Inspection
of
the air damper and linkage bearings
should be performed on a more frequent basis
if
the boiler is operating in a dirty environment.
The fuel
cam
profile spring should be inspected
monthly for wear, scoring
or
distortion.
If
any
of
these conditions are found, the cam
or
cam spring
must be replaced immediately
to avoid the
pos·
sibility
of
breakage in service. Use care
to
avoid
damaging the
cam
or
spring during installation.
Lubricate the
cam
spring occasionally with a
non-gumming,
dripless,
high-temperature
lubricant such as graphite
or
a silicone derivative.
CAUTION!
Combustion
should
be
checked
and
readjusted
as
required
whenever
the
burner
is
removed
or
any
control
linkage
Is
dis·
turbed
In
order
to
avoid
damage
to
the
equipment.
L.
FORCED
DRAFT
FAN
Figures 7-4 and 7-5 show the flow
of
secondary,
or
combustion air through the intake opening,
connecting the duct housing and impeller.
The position
of
the impeller vanes with relation
to
the air intake housing is extremely important
to
the output capacity
of
the fan. The impeller
vanes should not rub
or
contact the air housing
but at the same time the clearance must not be
more than .030 inch and preferably less.
The inset at lower right
of
figures 7-4 and 7-5 is
a view
of
the impeller from the motor side
in·
dicating the direction
of
the rotation.
The inset at the upper right shows a designation
of
"clockwise" and "counter--clockwise'' as the
terms are
used
throughout this manual.
<.:heck
occasionally
to
see that the fan
is
securely
tightened
to
the motor shaft.
If
the boiler
is
installed
in
a dusty location, check the vanes for
750-150
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