nicknoxx wrote:

Hi all

Our chimney is lined with a 6" flue liner. Is is possible/advisable to
try to connect a woodburner with a 7" flue to the liner, and if not,
what problems are there likely to be?

It's not recommended because the stove with the 7" flue probably needs that
size to get the gases away, flue gas massflow is proportoinal to heat
output.

The chimney (and its seal to the stove) maintains a depression in the stove
so that any small leaks allow air to enter the stove and prevent noxious
gases getting into the room. Effectively constricting the flue gases will
reduce this depression (or draw).

OTOH a 6" pipe is the mandatory minimum for a woodburner even if the stove
outlet is 5".

AJH