Refractories; Creosote Formation And Removal - Lennox MP-420D Homeowner's Care And Operation Instructions Manual

CREOSOTE FORMATION AND REMOVAL

When wood is burned slowly, it produces tar
and other organic vapors, which combine
with expelled moisture to form creosote. The
creosote vapors condense in the relatively
cool chimney fl ue of a slow-burning fi re. As
a result, creosote residue accumulates on the
fl ue lining. When ignited, this creosote makes
an extremely hot fi re.
The chimney should be inspected at least twice
yearly during the heating season to determine
if a creosote build-up has occurred.
If creosote has accumulated, it should be re-
moved to reduce the risk of a chimney fi re.
If creosote build-up is found, do not use chemi-
cal chimney cleaners that are poured on a hot
fi re. The chemical cleaners can be dangerous
and generally only work on the fl ue section
nearest the fi re, leaving the rest of the fl ue
unaffected. It is best to take the time to clean
the fl ue as previously described or have the
chimney professionally cleaned by a qualifi ed
chimney sweep.
8

REFRACTORIES

All fi reboxes contain a furnace refractory fl oor,
sides and back. These refractories are reinforced
with steel, but can be broken by improper use.
Dropping logs on the bottom refractory and
building fi res directly against the refractories
can cause premature burnout of these com-
ponents. It may easily be repaired or replaced
at costs far below repair and maintenance for
masonry fi replaces.
Proper care and "burn-in" of the fi rebox will
prolong the period of enjoyment without ex-
tensive maintenance. For the fi rst few uses,
build small fi res – not roaring infernos. The
materials used in the refractories contain and
absorb moisture. It is important to "cure" the
refractories by building only modest fi res. Under
normal usage, it is expected that hairline cracks
will appear in the refractory surface. These
hairline cracks do not affect the safe operation
of the fi replace.
Refractories should be replaced when:
1. The crack opens more than 1/4" (6.4 mm).
2. Pitting in the surface is extensive and pits
become deeper than 3/16" (4.76 mm).
3. Any piece of refractory larger than 2" (51
mm) in radius and 3/16" deep becomes
dislodged.
If conditions 1, 2 or 3 occur, the refractory
should be replaced.
NOTE: DIAGRAMS & ILLUSTRATIONS ARE NOT TO SCALE.
STAINLESS STEEL OUTDOOR WEATHER
COVER
An optional Stainless Steel Outdoor Weather
Cover can be purchased to provide additional
protection against leaves and other objects
that wind can carry which can accumulate
inside your fi replace or damage your fi replace
Glass Doors. Complete instructions for use are
provided with the cover.
OVERFIRING
• The fi re must always be confi ned within the
boundaries of the fuel grate.
• Do not build excessively large or hot fi res.
• Extreme temperature changes can cause
glass breakage — do not build a hot fi re and
close the glass doors if the doors are cold.