Crown Boiler 24-09, 24-11, 24-10, 24-08, 24-12, 24-06 Draw-Up Rods Alternating Pattern Manual Draw-up

Figure 9: Draw-Up Rods (Alternating Pattern -

Manual Draw-up)

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

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.

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.

WARNING

Sealant must be properly applied to ALL grooves. Failure to properly seal the boiler joints will result in combustion gas leaks through to joint. DO NOT operate boiler with combustion gas leaks. The sealant should be applied before each section is placed on the assembly.

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

16