Can I vent my stove directly into the fireplace?

Hello CoalBrookDale, and welcome

Not sure where you are located, (from the link it looks like the UK?, or is the stove you are looking at installing from the UK?), but the first thing you should do is check to see what the local building code says and act accordingly.

A quick answer would be that at the very least you will need a block off plate to keep smoke from pouting into your house in case of a downdraft.

I personally would be more comfortable with a fully lined chimney. Do a search on "chimney liner" and a number of other threads will pop up.

Do you have a manual for this stove? It should tell the different venting options. Local codes may apply here to. You will definitely need a block off plate and at least a few feet of pipe to go to the first clay tile to keep the down drafts and the heat from going up the chimney. Also agree with Willhound about full liner for best draft and easier cleaning.

If you have the larger Coalbrookdale, then your chimney probably meets the sizing requirements without reline - in other words, if the stove is 8", and the chimney in great condition, reline may not be needed - BUT, at minimum use a "tube" of 5 foot flexible stainless steel to go up toward the first flue tile AND a tight fitting block off plate as per the article. That is how our shop installed dozens of Coalbrookdales in years past with few problems.

If you are going to burn coal, make 100% certain that you install a CO detector! In fact, two would be the best bet. Coal gases can kill....another reason for having at least the tube and a very tight fitting block off plate.

Note, if you chimney is not currently lined with terra-cotta tile, then you MUST reline.

Note the reasons for full lining - easy cleaning, better draft, less downdraft - in general a tighter job. Consider it this way - if you had to run a pipe from your cars exhaust though your living area, would you feel better about it being in a nice tight stainless pipe, or a relatively porous masonry tunnel?

BUT, you may also run into problems if, for instance, you have an 8x12 flue - usually 6.5 x 10.5" inside - difficult to line with 8" (if your stove is 8")

Coal burning produces sulfuric acid which eats clay flue liners and concrete Coal requires cleaning in the spring afer the burning season to get the sulfur out of that chimney before the humid weather sets in, supplying the moisture the initiates the sulfuric acid formations. You may be able to use your existing setup. But a good 316Ti or 321 ti liner is added protection, that could prove to be money well spent. Don't know you size flue liners so, I can not advise how cross-sectional code applies. Is the chimney in an exterior wall? They do make round to oval band back to round ss liner to pass threw the damper. Again not the best for promoting good draft and stove opperations.

Welcome aboard

elkimmeg said:

Coal burning produces sulfuric acid which eats clay flue liners and concrete Caol requires cleaning in the spring afer the burning season to get the sulfur out of that chimney before the humid werather sets in supplying the moisture the initiates the sulfuric acid formations. You may be able to use your existing setup. But a good 316Ti or 321 ti liner is added protection, that could prove to be money well spent. ...

Welcome aboard

Click to expand...

The best thing about going this way is you get to preserve your tiles if they are in ok condition now. The liner can be replaced relatively easily and cheeply by comparison with the tiles and you have a safer better drafting chimney.
...to do it with 316Ti you are looking at about $600 - $1,000 with insulation and not including any labor depending on the height of your chimney... 316 is also rated for coal and might be a little less ...or you could do it without insulation and save about $200...