Gas Fire Flues - which Trader is Correct ?

[ricky101]

Hi,

Would appreciate some independant advice regarding having a replacement gas fire fitted.

The old gas fire c. 1980 has a worn out valve which is now obselete, but otherwise burns well.

Its a wall hung fire and the flue is a breeze block sized , concrete block with flue hole in its centre, built into the breeze block inner wall. (cavity party wall )
Its an almost vertical rise to the outlet on the bungalows roof with is a 1980s Marley Modern Tile using a Gas Ridge Vent tile with a single opening on each side.

So far we have had the following statements -
A single outlet vent is not suitable, it must be an double or extended type,
it must be a metal terminal.

That type of flue is no longer legal and any new fire must have a new flue pipe , which could only be fitted inside the room. ( not what we want )

So as you can see we are somewhat surprised at the varied advice.

 

[Agile]

Does this fire have a metal flue liner?

They should be replaced with a new appliance!

 

[ricky101]

Does this fire have a metal flue liner?

They should be replaced with a new appliance!

Hi,

No, its just the bare concrete of the block; a rectangular hole, from what I remember when I last looked up it during a check up.

Do not think its wide enough for a metal liner partic towards the roof ridge where the last flue blocks are offset diagonally to meet the ridge.

 

[ollski]

You mean its a bog standard precast flue?

 

[Dan Robinson]

Methinks an engineer is making more work than required .

 

[ricky101]

You mean its a bog standard precast flue?

Seems to be ...

 

[ricky101]

Methinks an engineer is making more work than required .

Thats why I'm asking ...

 

[Dan Robinson]

There will be a metal liner going the last part in the loft. I used mine rather handily to drop network cables down that side of the house. I got rid of the fire altogether.

 

[ServiceNumpty]

Precast flue, although without checking it may have a liner from the transfer block to ridge vent - although unlikely.

 

[Dan Robinson]

Precast flue, although without checking it may have a liner from the transfer block to ridge vent - although unlikely.

Mine does/did.

 

[Newboy]

Or an asbestos cement flue pipe from the top of the flue to the ridge vent - helpfully connected by a nice asbestos rope gasket!

 

[oilboffin]

Asbestos bbbbrrrrrrrrrrrrrrrrrr

 

[ianmcd]

I like most have Gas Fires on my Gas safe registration so no one is more qualified than us but it is just a general qualification you either can or can not work on them , but like most of us we dont touch gas fires, get someone who specializes in them @FiremanT on here comes to mind try PM him there are others but personally I hate the feckin things and please dont mess around with it yourself they are so dangerous if you get it wrong

 

[FiremanT]

Who is giving this "advice"?

I have no idea what he is reffering to re. the terminal. Can you post pics for someone here to see? I am off on hols so will not be able to post further.

As was said, you have a "pre cast flue". the early ones had a smaller cross sectional area, 1300mm so can be problematic,and fires will normally specify the later ones, making the early ones non compliant, although this seems to be routinely ignore. The later ones from 1986, have bigger CSA (1650mm) .
The loft section will either be "asbestos" type material, or if replaced, twin wall metal. However, many are fitted with flue liner which has NEVER been compliant, and no fire should be replaced using this. It must be changed to twin wall. If an existing fire fitted with flue liner passes all the tests, it can be left on. Some early ones had a connecting flue of 4", which is no longer allowed.
This is quite a good article, although it reads as if PCF were introduced in 1976 - but they were definitely around well before then.

http://www.installeronline.co.uk/wp-content/uploads/2013/03/Stacking-up.pdf

IMO, if you are changing the fire, consideration should be given to a balance flue fire, assuming you have an outside wall. PCF's are without doubt the least reliable of all flues types. If the wall is hard plastered, as opposed to board dot and dabbed, a fire will often cause cracking of the plaster. It does seem, in my experience, that a newer fire is more likely to cause this problem than an old one.I have no idea why, apart from maybe a greater heat input.
I would find a local fireplace showroom, and pay for their advice. It is all very well grabbing an internet bargain, but finding a RGI who is competent, registered AND experienced with fires or open flue does seem to be something of a challenge.

As it happens I went to a 10 year old fire yesterday. 2 other had had a go, one said replace it, the other said he would investigate the parts required, but never returned. His 3rd RGI contact declined the work, and suggested me. In about an hour I had it working and given a full service.

Finally, as Ian said, DO NOT TRY THIS YOURSELF AT HOME. The article is for info.only

 

[ricky101]

Thankyou Fireman, happy holidays ..

The fire is on the party wall and just looking behind the insulation on the pipe from the transfer block to the ridge vent its a 5ft length of a precast concrete /asbestos ? and a diameter of about 9"

We did find that Stacking Up page late last night and seems we have a 1980 class1 type of earlier flue , basically seems its not suitable for any new gas fire.

If we have this smaller opening class1 would it be possible to insert a liner into it ?

We really do not want a stove type chimney in our smallish lounge.

No, not work to do ourselves, just want to find out what the correct method should be.

DIY Gas is a total NO, NO.