Cleaver-Brooks CBH 40 - Door Closing and Sealing

Wash-coat the lower half of the rear door refrac-
tory prior to closing.
The upper half of the door contains a lightweight
insulating material similar to that used in the in-
ner door. A thin wash-coat mixture applied gently
with a brush is helpful in maintaining a hard sur-
face.
If the baffle tile or the refractory requires replace-
ment, contact your local Cleaver-Brooks repre-
sentative or write to the Cleaver-Brooks Service
Department for a copy of bulletin C10-4101 cover-
ing major repair or replacement of rear door
refractory.
Front Inner Door
The front inner door is lined with a lightweight
castable insulation material. Thin, "hairline"
cracks may develop after a period of time, how-
ever, these will generally tend to close due to ex-
pansion when the boiler is fired.
A
thin wash-coat mixture applied gently with a
brush is helpful in maintaining a hard surface.
Minor repairs can be accomplished by enlarging or
cutting out affected areas, making certain that
they are clean and then patching as required.
Should the entire installation require replacement,
remove existing material and clean to bare metal.
Inspect the retaining pins and replace if necessary.
Reinforcing wire suitably attached may also be
used. The recommended insulation is known as
Vee Block Mix and is available in 50 lb. bags (CB
Part Number 872-162).
Mix the material with water to a troweling con-
sistency. Mixing should be completely uniform
with no portion either wetter or drier than another.
Trowel this mixture into any areas that are being
patched. If replacing complete insulation begin at
bottom of door and apply the mixture to a thick-
ness equal to the protecting shroud. With a trowel
apply horizontally back and forth across the door
in layers until the required thickness is reached.
Allow to air-dry as long as possible. If immediate
use of boiler is required, fire as slowly as possible
to avoid rapid drying of the material.
Furnace Unerr
Maintenance consists of occasional wash coating of
the entire liner. Face all joints or cracks by apply-
ing high temperature bonding mortar with a trowel
or fingertips. This should be done as soon as cracks
are detected.
Should segments of the liner burn away or fall out,
replace the entire refractory. Any refractory that
may break out should be removed as soon as detec-
ted so that it will not fuse to the bottom of the fur-
nace and obstruct the burner flame.
If replacement is necessary, refer to Chapter 7 and
Chapter &--Adjustment and Maintenance
order proper replacement materials. Remove exist-
ing refractory and thoroughly clean that portion of
the furnace covered by the liner to remove all old
refractory cement or other foreign material to in-
sure new liner seating firmly to the steel. Inspect
furnace metal for soundness.
It is recommended that the tile be dry fitted, match
marked, removed and then reinstalled with the
proper amount of refractory cement. Thin joints
are desirable. Generally it will be necessary to
shave a portion from one or more tile to obtain a
fit.
If a fill piece is required, cut it to fit and install
this piece at the bottom of the furnace.
Allow refractory to air dry as long as possible. If
immediate use of boiler is required fire at low rate
and intermittently if possible.
N. DOOR ClOSING AND SEAUNG
Whenever the front or rear door is opened for in-
spection, the head gaskets should be checked for
hardening and brittleness. Doubtful gaskets should
be replaced. Coat the gasket with an oil and
graphite mixture before closing the door. Make
certain that all gasket retaining rivets are in place.
The flange of the door should be clean and free of
any hardened cement, scale, etc.
Check the condition of the rope used as a baffle
seal. Replace if necessary. If the rope is in good
condition, liberally coat it with an insulating pulp
prior to closing. Make sure that the rope is properly
positioned.
If it is necessary to replace the rope, wire brush the
tube sheet area to remove all old sealing material.
Place a new piece of 1-1/2" diameter rope
( 853-924) on the lip of the baffle tile. Hold it in place
with furnace cement or an adhesive.
NOTE: Earlier models had several steel bar seg-
ments tack welded across the tube sheet to
serve as a gasket retainer for 5/8"
diameter rope. It is suggested that these
bars be removed and 1-1/2" diameter rope
used.
Generously apply a seal, consisting of a pulp mix-
ture of insulating cement and water, around the
entire rear door circumference. Place the pulp
around the inside diameter of the head gasket as
shown in Figure 5-8. Also coat the tube sheet area
adjacent to the baffle tile.
When the door is closed, the pulp will compress to
protect the tadpole gasket and to form a seal be-
tween the refractory surface and the tube sheet.
The insulating pulp seal is not needed or used on
the front head. Make sure that gaskets are in posi-
tion when closing.
When closing the door, bolts should be run in snug
and tightened evenly to avoid cocking door and
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