Gas Fire Flue?

[theiron]

Evening all

Over the past few months iv been renovating a house, so iv been a bit of a lurker on here for a while, but only now have i had the need to post a question.

The house previously had a back boiler fitted, which has now been removed and a condensing combi boiler fitted. I'm now ready to have a gas fire fitted where the back boiler used to be. There's an aluminium flexible liner in the chimney which took the flue from the back boiler. My plumber has told me to line the top of the recess in the fireplace with fireboard and seal it with fire cement, but cut out a circle for the chimney liner. So basicaly the whole of the chimney would be blocked off, apart from the chimney liner. The logic been that even though the liner isnt connected to the fire, the draw from it would pull the flue up it. Obviously with it been something as critical as a gas fire when it comes to safety, i thought id ask you guys for your opinion.

And just to add;

The plumbers CORGI

He said he'd smoke test it first


Any input is greatly appreciated

 

[Blackcatgas]

Yes, that sounds right.

 

[theiron]

thanks for the prompt reply

does it matter that its an existing chimney liner? i.e. do i not need a new one?

also, do the sides and back of the recess in the fireplace not need boarding?

thanks again

 

[Blake]

You need to look at the Manufacturers instructions for the fire you wish to install. The installation instructions will inform you of the acceptable method of installation with regards to chimney etc.

 

[theiron]

thanks bronzino

the manufacturers instructions just say that the fire is suitable for a class 1 chimney. So does this include a class 1 chimney (which it is) with a liner? The house is 100years old and i wouldnt be overly confident of just sending the flue up the chimney incase of any defects with the chimney itself.


thanks

 

[stevetheplumber]

you need a regidtered installer to fit the fire he will do flue checks

 

[aggis]

Get a G S engineer , a 5" flue liner isn't a class 1 chimney.

 

[Bartdude]

Most gas fires don't require a chimney liner but it will depend on the MI's and the condition of the chimney. To re-use a liner you have to be able to confirm it's in good condition,if it's been in place for a long time that might not be the case.

New Appliance = New Liner

 

[Billy Bob Bob]

and to reiterate what bartdude said ,the liner must be good for another 15 years,so you cant say the old one will,so get a new one i would look for another gsr engineer,he is going to use a un proven old liner that could be like a colander out of site and still pass a flue flow and hes asking you to do flue work

 

[yorkieplumber]

Agree with above new liner required, you dont know the condition of the existing one, for example is it in one continous length, play it safe
g s engineer should do all checks regarding flue pull etc

 

[tamz]

A class 1 flue is a standard 9 x 9" chimney or a minimum 7" liner.
The boiler flue is 5", class 2. It is too small.

Pull it out and get the chimney checked and get someone who knows what they are doing to fit it.

 

[Billy Bob Bob]

just seen the class 1 part and the fact your guy wants to use a 5 inch liner ffs

 

[theiron]

when i said its a class 1 chimney i meant that the original chimney was a class 1 (providing im right in saying a class 1 chimney is a brick one). But it has since had a flue liner fitted when the back boiler was fitted. I probably didnt explain myself well.

From what i gather having a new liner fitted is quite an expensive job, and in todays climate im inclined not to spend the money on it. But gas is gas, and as you guys know, you don't cut corners.

So having said that, i think i might just put an electric fire in, or put the gas fire in and not have it connected up (so its not functual, just there for looks).

Thanks for all you advice and help

 

[Bernie2]

Standard good practise is to renew the liner. Class 1 fires require a bigger flue than an ordinary gas fire so check fires MI's.

In practise a flue liner may look good but when you pull the old ones out they often fall apart in your hands. The old 9" x 9" flues where for coal fies and the old acidic soot deposits left in the flue after brushing, if it was brushed before the liner was fitted, could seem to attack the liner from the outside, the liner can go a reddish colour or turn to white powder.

Sorry for not being more technical.

But you can't always tell just by looking at a liner if its okay and obviously you can't see all the way up its length. Also you don't know if a liner was put in because the flue was leaking.

So generally they go on its age, its probably the easiest thing to do. I imagine its an old liner and had loads of wear from a BBU and a possible fire front. You could replace it yourself buts its labour intensive and you need roof work gear. Its tempting to leave it because of costs of course but then you have to balance the cost against safety and safety should always win.

 

[gasmarc]

get someone who knows what he is doing is the first thing I would do. New appliance = New flue

 

[theiron]

thanks for the help guys. Like i said before, iv decided not to bother with a gas fire now. The other half has decided she just wants a feature making out of the fireplace now.

Thanks for all the advice

 

[gasmarc]

you can always fill it full of booze lol