When it is not possible to get enough draw to make a fireplace or stove work properly you need an Exhausto chimney fan. These chimney fans are designed to work at high temperatures and suck the air from your chimney creating an artificial draw.
These solidly built Flue chimney fans are a British made product that solve the problem of flues that smoke back into the room, or that won't draw properly.
An inline chimney fan is relatively easy to install and a way to improve chimney draw if all other avenues have failed. They can also be handy for log gasification boilers to stop smoking when reloading (although our Arikazan models do not suffer from that problem).