19
NOTE-A series of wood "break in" fires should be done
before attempting to burn coal (see page 17).
Coal Burning:
Do not burn coal on the wood grate. An optional coal grate
kit is available for the cookstove (#4500) to burn coal. An
installation and operating manual is packed with every
Blackwood Coal Kit. Extra copies may be obtained from
your dealer or by contacting AGA Marvel. Below is a brief
description of the coal kit installation.
Storage of Coal:
Store coal in a dry, well ventilated area.
Coal Grate Installation:
To install the optional coal grate, remove the lift handle, the
key plate and lids. Lift the wood grate out through the top
of the firebox and replace it with the coal grate. Remove
small front brick in firebox by unscrewing bolt & nut that
holds brick in place. Replace with large brick in coal kit.
Gently tap the coal grate down until it fits snugly into the
steel track. Replace the key plate, lift handle and lids. Then
proceed with firedoor damper installation.
Firedoor Damper
(Coal burning only, see Figure 24.)
The firedoor damper comes with each coal kit and must be
installed. Remove the black firedoor frame from the fire
-
door. Loosen the three screws that hold the cover plate
over the damper holes. Replace the cover plate with the
coal damper, lettered side out. Tighten screws just enough
to hold the damper plate on but also allow it to slide freely
back and forth. Lock screws in position with a nut on each
screw thread.
C
O
Starting Up a Coal Fire
A chimney 6" (15.25 cm) in diameter is imperative for the
Coal Burning process. A chimney larger than 6" (15.25
cm) in diameter will cause poor ignition of the coal due to
inadequate draft.
It is possible to burn coal with a large diameter chimney,
but banking a new bed of coals will require a greater mix of
wood to create and maintain an adequate draft.
The minimum draft required to maintain an oven tempera-
ture of 350º F (175C) is around .04" (1.016 mm) on a water
column. For drafts under .04" (1.016 mm) on a water col
-
umn, closing the oven draft damper more than half way, will
cause back puffing.
During the recharge phase of a new bank, a draft of .08"
(2.03mm) should be maintained for at least 10-15 minutes
or until a substantial bed of red embers is built up.
We recommend burning anthracite coal, which is relatively
clean to handle, burns evenly with a low flame, has a low
sulphur content and produces relatively little smoke.
Use a "chess nut" or "nut" size of coal, which is 1
3
⁄
16
to 1
5
⁄
8
in (3 cm to 4.13 cm) diameter. However, other coal, such as
bituminous, can be burned, but is inferior to anthracite.
To Start a Coal Fire:
1. Use paper and dry wood kindling to start the fire.
2. Add small, compact pieces of hardwood when the kin-
dling is burning hot. Keep the primary damper controls
fully open to establish a hot fire quickly. The ash door
also may be opened during start-up to accelerate the
initial burn.
3. When a substantial bed of red embers is built up, start
adding coal – small amounts at a time. Keep the draft
control open.
Figure 24
Illustration showing
firedoor
damper installation
COAL BURNING
NOTE