United States Stove 24AF, 24AG, 24AZ owner manual Ashes, Clinkers

ASHES

Ashes never should be allowed to accumulate in the ash pit so that they in any way impede the flow of combustion air to the fire. Excess ash accumulation can cause the fire to go out and also can cause severe damage to the grates because of the absence of a cooling flow of air beneath them.

Ashes always should be emptied into a metal container. Coals can remain hot many hours after a fire is out. Coal ashes should not be put on gardens as they do not contain beneficial minerals like wood ashes, and may cause ground water pollution.

Coal produces considerably more ash than wood, so the intervals between emptying are much shorter. For equal heat output, coal will produce seven (7) to ten (10) times more ash than wood.

CLINKERS

Clinkers can occur in any coal furnace during the process of burning. These are hard pieces of fused ash that form in the firebox. They can become hard and large in size and, therefore, cannot be shaken through the grates in a coal stove. When there is an appreciable accumulation, the fire will go out because insufficient air is allowed to pass through the clinkers to the burning coal.

Once large clinkers have formed, they can be removed only from above the grates. This usually means the fire must be allowed to go out before they can be removed.

Clinkers formation can occur from a number of different causes or a combination of causes. Some of these are:

•Poor quality coal-excess ash content and/or too low a heat of fusion.

•Too hot a fire (too much draft).

•Too shallow a bed of coals.

•Too deep a bed of coals.

•Excessive Shaking.

•Poking the fire from the top.

•Too little air (draft) after a long, hot fire (caused by rapid adjustment of draft from a very high setting to a low setting).

If clinkers do form, the coal quality should be checked first, and then all the above points should be reviewed and corrected.

SAFETY

Whenever a loading door is opened, the bypass damper should be opened first (use a glove to protect you hand), and the door should be cracked slightly (for about ten (10) seconds) to allow oxygen to enter and burn any combus- tible gases that are present before fully opening. Failure to do this could result in sudden ignition of the unburned gases when the door is opened.

With the exception of the start-up period, the ash pit door should never be left open. Serious damage to the stove can occur from overheating. In extreme cases, this over- heating could be the cause of an "unfriendly fire".

Coal furnaces are subject to the same installation clear- ance standards as wood furnaces. Never burn coal in any furnace that does not have an airtight, unified chimney system.

Coal furnaces should not be installed in any chimney that has had a history of back-drafting or flow reversal. Also, coal furnaces should not be installed in any chimney hav- ing an excessively large flue. These conditions can cause improper draft, resulting in carbon monoxide entering the house rather than being drawn up the chimney. Remem- ber, coal gases are toxic.

Sulfur dioxide, sulfur trioxide and other ions released from coal burning may corrode stainless and masonry chim- neys, and even terra cotta chimney liners and brick in nearby buildings. Coal with high sulfur content will de- stroy chimneys especially fast if soot sits in the flue for extended lengths of time. It is important to clean chim- neys regularly.

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