Hole identification
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Maybe at some time there was a water heating system on it. Is there a similar hole anywhere else?
On top of a coal stove this looks like a check damper. Notice the ramp that would raise a flat plate as it is rotated.
A check damper works like a barometric damper that allows air into the chimney to cool the rising gases to slow them down. When open, this is closing a manual flue damper.
Coal requires all air to come up through it from under the grate. Air leaks around doors on antiques add oxygen above the fire to ignite coal gas being expelled from fresh coal as it heats. This is secondary air. Any leaks above the fire or into pipe or chimney is indoor air rushing in that cools the rising gases to slow draft. This would be opened overnight to extend burn, closed when you want more draft bringing in more air for more heat.
A check damper cannot be used with wood. This allows indoor air to cool the flue gases forming creosote. Coal has no smoke particles to form creosote, so the chimney runs about half the temperature of wood.
Another trick was tilting the lid slightly to allow indoor air to rush up the stack cooling the flue.
Antique flue dampers had a metered hole in the center to close fully when up to temp unlike wood that only uses the damper to slow an overdrafting chimney, or slow a coal stove with wood that gets too much air from leaks everywhere. Wood uses air from any direction and will overheat a coal stove easily.
Coal only burns harder with air coming up through it, every other leak slows it down.
Always go back to the basics when figuring out a stove control. Hot rising exhaust gases in the chimney causes a low pressure area in the flue, pipe, and stove. This allows the higher atmospheric air pressure outside of the system to PUSH into the stove intake, feeding the fire oxygen. Any other leaks into the stove, pipe or chimney flue allows the higher pressure in, not smoke out.
A common hole on top is also for a swing out finial. It is swung open to expose stove top for loading or cooking. They normally have a stop to prevent swinging too far, not like this one with a ramp. And the hole is only large enough for a bolt to go through with a nut on the bottom.
The lid is opened for loading or direct contact with pan or kettle for cooking. If it has a round cylinder inside, this is a magazine that gravity feeds coal to grate. Need more pics.
A check damper works like a barometric damper that allows air into the chimney to cool the rising gases to slow them down. When open, this is closing a manual flue damper.
Coal requires all air to come up through it from under the grate. Air leaks around doors on antiques add oxygen above the fire to ignite coal gas being expelled from fresh coal as it heats. This is secondary air. Any leaks above the fire or into pipe or chimney is indoor air rushing in that cools the rising gases to slow draft. This would be opened overnight to extend burn, closed when you want more draft bringing in more air for more heat.
A check damper cannot be used with wood. This allows indoor air to cool the flue gases forming creosote. Coal has no smoke particles to form creosote, so the chimney runs about half the temperature of wood.
Another trick was tilting the lid slightly to allow indoor air to rush up the stack cooling the flue.
Antique flue dampers had a metered hole in the center to close fully when up to temp unlike wood that only uses the damper to slow an overdrafting chimney, or slow a coal stove with wood that gets too much air from leaks everywhere. Wood uses air from any direction and will overheat a coal stove easily.
Coal only burns harder with air coming up through it, every other leak slows it down.
Always go back to the basics when figuring out a stove control. Hot rising exhaust gases in the chimney causes a low pressure area in the flue, pipe, and stove. This allows the higher atmospheric air pressure outside of the system to PUSH into the stove intake, feeding the fire oxygen. Any other leaks into the stove, pipe or chimney flue allows the higher pressure in, not smoke out.
A common hole on top is also for a swing out finial. It is swung open to expose stove top for loading or cooking. They normally have a stop to prevent swinging too far, not like this one with a ramp. And the hole is only large enough for a bolt to go through with a nut on the bottom.
The lid is opened for loading or direct contact with pan or kettle for cooking. If it has a round cylinder inside, this is a magazine that gravity feeds coal to grate. Need more pics.
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