Flue liner

[shooterjim]

Hi all. Is it legal to run a twin wall flexi down an existing pre cast clay gas flue? Want to fit multifuel burner. Hetas man last night said not!

[treequip]

If he said its ilegal he is talking through his arse, there would need to be a law against it for that to be the case.

 

There are however building regilations to comply with.

 

Check with your LA's building regs people, they will have the facts and no axe to grind.

[Alycidon]

No need to put a flex liner down an existing clay liner assuming its a class 1 flue, ie round or square and at least 7 inch diameter or square. Only times you may need to is if the chimney is unsound. or you cant get an airtight seal on the bottom register plate.

 

A flexi liner does though help stove efficiency, some installers wont install without using a liner. Certainly not illegal though.

 

A

[adie.k]

hi.

he might be right if the liner in question is jointed the wrong way. some gas installs are put in upside down and therefore not suitable for solid fuel. your other post is right though, it does help with flue performance and output off the stove. what type of appliance is it?

[shooterjim]

Only measures 6.5" where it is round. The rectangular restriction is roughly 4x3". Going to chop into chimney Brest in lounge where it appears from below to open up again. If it does then will be able to get a 6" flexi down.

[niftysteve]

No need to put a flex liner down an existing clay liner assuming its a class 1 flue, ie round or square and at least 7 inch diameter or square. Only times you may need to is if the chimney is unsound. or you cant get an airtight seal on the bottom register plate.

 

A flexi liner does though help stove efficiency, some installers wont install without using a liner. Certainly not illegal though.

 

A

 

also would fit a liner if the clay liners are fitted the wrong way up i have looked at 4 installs this week with exactly that

[Alycidon]

also would fit a liner if the clay liners are fitted the wrong way up i have looked at 4 installs this week with exactly that

 

True, in fairness I cant say I have ever come across one, not sure that I would recognise one other than when you can see the bottom edge of the bottom liner.

 

I did come across a 7 inch square clay lined last week that had had a large lump of the clay liner drop down the chimney, that will be done with a liner if we get the job.

 

Putting solid fuel fumes up a gas liner is illegal. Gas fumes can go up a solid fuel liner ok but not the other way round.

 

A

[Alycidon]

Only measures 6.5" where it is round. The rectangular restriction is roughly 4x3". Going to chop into chimney Brest in lounge where it appears from below to open up again. If it does then will be able to get a 6" flexi down.

 

Sounds like it is a class two flue, (gas only). You need a DEFRA approved stove here with a 5 inch outlet, then you can use a 5 inch id liner. That should go down a 6.5 inch round chimney but it will be pretty tight. There is no way on earth that you will get a 6 inch ID ( so 6.25od approx) down a 6.5 inch chimney. Dont forget the cowl on the roof, that will probably need changing to a solid fuel one. Post a pic of the top of the chimney if in doubt. If no chimney and its venting through a tile on the ridge then its gas only, unlikely by the sound of it.

 

A

[Stubby]

I got (just) a six inch liner down a seven and a half inch round clay . The guy who hepled me said there is a right and a wrong way up .

[Alycidon]

I got (just) a six inch liner down a seven and a half inch round clay . The guy who hepled me said there is a right and a wrong way up .

 

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

 

A