Flue liner

[Stubby]

There is, the better brands are marked with an arrow to show the direction of flow.

 

A

 

Now you say it there were arrows along it about 2feet apart.

[finny]

Don't rely on the arrows alone tho..we have had two instances of liners with arrows printed the wrong way up!! You need to check that the inside of the liner spirals downwards, you should be able to feel the sharp edge..

It's true that you can sometimes get away with no liner if their is a sectional clay system in place, as long as it passes a core and smoke test, however, that is no guarantee of how long it will remain tight.. best to drop a liner..