17
The sections must be assembled according to the
arrangement shown to ensure proper operation,
proper assembly of canopy, jacket and alignment
of piping and tankless heaters with jacket
knockouts. Start with the back section and work
towards the front.
Use a brush to clean the groove in the face of
the next section. Then, using a cartridge of RTV
6500 or RTV 736 sealant in a caulking gun, ll
the groove in this section with the silastic sealant.
Touch-up any missed spots before draw-up.
Touch-up after draw-up has no value.
This is a forced draft red boiler and sealant
must be applied where specied for proper
and safe performance. Burnham Commercial
has approved section joint sealants (silastics)
manufactured by Dow-Corning under the product
number RTV 736, and Sil-Bond under the product
number RTV 6500.
Sections must be drawn-up tight immediately
after properly applying sealant for best results.
Although sections may be joined within two
(2) hours of applying sealant, humidity and
temperature affect cure time. If a “thick skin”
has been formed on the sealant bead, remove
and re-apply sealant.
Sealant must be properly applied to ALL boiler
joints. Failure to properly seal the boiler joints
will result in combustion gas leaks through the
joint. DO NOT operate boiler with combustion
gas leaks.
j. Clean and lubricate nipple ports on next section
to be assembled and place on nipples previously
installed in rear section. To facilitate assembly,
it is advisable to enter the upper nipple rst in
its port. Then enter the lower nipples in their
respective ports. If necessary, place a lifting bar
(crowbar) under the center of the section and
lift the nipple port onto the upper nipple. Drive
section in place with a heavy block of wood,
striking blows as squarely as possible over nipple
ports.
k. Large draw-up rod lugs with dual holes are cast in
the four corners of each casting. STARTING WITH
THE UPPER HOLES, install four 3/4" x 11"
long draw-up rods along with washers and nuts
(see Figure 9).
To avoid damage to the draw-up rod threads while
drawing up sections, apply oil or other lubricant
to tie rod threads while assembling sections to
prevent stripping of threads on rod and to make
assembling easier.
l. DRAW UP SECTION SLOWLY AND
EVENLY using an alternating pattern starting
with the upper right lug (closest to the 7" port)
and proceeding to the lower left , lower right
and nishing with upper left lug. 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 should continue
to squeeze out wafer thin until the sections are
connected 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, use a feeler gauge to measure any gaps
at the locations identied in Figure 9. (Unless
specied otherwise, gaps should be measured at
these locations on both sides of the sections). A
maximum gap of .025" is acceptable. Measure
gaps at the outer edge of the connection only,
making sure not to puncture the gasket created
by the silastic and rope.
Figure 9: Connection Inspection Locations and
Manual Draw-Up Tie Rod Pattern