Warning – Crown Boiler 24-07 User Manual
Page 16
16
When you start, grind surfaces between
adjoining sections should be approximately
3/8” apart. Use three (3) or four (4) passes at
tightening the four (4) draw-up rods a little at
a time so that sections are pulled up evenly.
During the last pass, pay close attention to the
silastic sealant as it squeezes when the sections
come in close contact. The silastic sealant will
continue to squeeze out wafer thin until the
sections are connected metal to metal. While
tightening the nuts, close attention should be
given to the connection area to determine that
the silastic has stopped squeezing out from
between the sections. This will give assurance
that the sections are assembled metal to metal. If
the silastic has stopped squeezing out from the
connection and the sections still do not appear
to be drawn metal to metal, measure any gaps
between the sections with a feeler gauge. A
maximum gap of .025” is acceptable. Gaps
should be measured at the outer edge of the
connection. DO NOT PUNCTURE THE
GASKET CREATED BY THE FIBERGLASS
ROPE AND SILASTIC
SEALANT WITH THE FEELER GAUGE.
WARNING
Do not over torque draw up nuts after grind
surfaces meet.
KEEP NIPPLES ALIGNED WITH NIPPLE
PORTS. If necessary, tap edge of nipples lightly
with a blunt tool or rod to keep nipples from
cocking while sections are being drawn-up. DO
NOT DRAW UP SECTION WHEN NIPPLES
ARE COCKED. If the torque required becomes
Figure 9: Draw-Up Rods (Alternating Pattern -
Manual Draw-up)
2. ASSEMBLY OF SECTIONS (HYDRAULIC DRAW-
UP)
The entire boiler assembly may be drawn up at one
time using hydraulic draw-up equipment providing
the operation is completed within four (4) hours after
application of the sealant.
a. Repeat steps 1a through 1k under “Field
Assembled Sections (Manual Draw-Up).”
b. Continue driving sections in place (in their
respective order) until all sections are in the
assembly. Ground surfaces between adjoining
sections should be spaced 1/4” to 3/8” apart.
Spacing of more than 3/8” will limit number of
sections that can be drawn up in one unit and
could indicate cocked nipples.
On long boiler assemblies, it may be necessary to
draw-up a partial block if the entire boiler is not
ready to be drawn-up tight within four (4) hours
of the first application of Silastic. If the block
assembly time extends overnight, the partial block
completed must be drawn-up tight before leaving
the boiler overnight. If a joint springs out, it must
be redrawn tight within four (4) hours of first
application of Silastic to the joint.
c. Insert the three (3) ¾” draw-up rods (and
couplings, if appropriate) through the tapped holes
in the rear section extending them through the
excessive, periodically place a heavy block of
wood over each nipple port and strike as squarely
as possible with several blows to relieve tension
on the draw-up rods.
n. CONTINUE ASSEMBLING SECTIONS IN
THEIR RESPECTIVE ORDER alternating
the draw-up rods from the upper to lower set
of holes in draw-up lugs. Be certain that all
sections are drawn up IRON-TO-IRON at all
three (3) nipple ports.
BE SURE TO APPLY THE SEALANT to
the groove in the ground joints between
adjacent sections as the boiler operates with a
positive pressure in the firebox and products of
combustion will escape between sections unless
the sections are properly sealed. The sealant
should be applied before each section is placed
on the assembly.
o. If a joint springs apart it must be redrawn tight
within four (4) hours of the time of application of
Silastic to that joint.
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