Stove pipe to flue increasing

[openspaceman]

It looks like a cast in situ (high alumina?) concrete liner to me.

 

The stove installer can pressure check it to see if it is still suitable and still sign off the installation.

[Alycidon]

Should be able to fit a clay liner adaptor to that,  as long as there is enough height above the stove,  looks like it will need a couple of elbows as well.  Maybe rear flue the stove straight into the CLA,

 

A

[Guest Gimlet]

Yep, looks like a solid flue cast-in-situ around an inflatable former. In which case it should be relatively easy to fit a clay to metal adaptor. It looks a simple job. 

regarding the cowl, if you've got to get up to the stack anyway to drop down a liner, I'd fit a new one as a matter of course. Usually they're cheap painted mild steel and the paint gets corroded by exposure to soot and tar and they rust away. If the chimney is very high and tricky to access I'd fit a 6" stainless suspended cowl. They cost more but they don't disintegrate and get blown off the pot in the middle of winter. 

 

 

[Alycidon]

11 hours ago, Gimlet said:

Yep, looks like a solid flue cast-in-situ around an inflatable former. In which case it should be relatively easy to fit a clay to metal adaptor. It looks a simple job. 

regarding the cowl, if you've got to get up to the stack anyway to drop down a liner, I'd fit a new one as a matter of course. Usually they're cheap painted mild steel and the paint gets corroded by exposure to soot and tar and they rust away. If the chimney is very high and tricky to access I'd fit a 6" stainless suspended cowl. They cost more but they don't disintegrate and get blown off the pot in the middle of winter. 

 

 

We always use stainless, sometimes loose jobs because we are more costly but quality costs money,

 

A

Edited June 2, 2021 by Alycidon

[slim reaper]

If that steel to concrete adaptor fits the id of existing flue you will loose the socket up effect so moisture/tar running down can seep through the joint and run down the outside of the metal flue.

 

[Guest Gimlet]

Error in my last post. If the OP is able to fit a 6" flexi liner inside his existing flue, he won't need a clay to metal adaptor. He can just go from stovepipe to flexi in the usual way.

[openspaceman]

1 hour ago, slim reaper said:

If that steel to concrete adaptor fits the id of existing flue you will loose the socket up effect so moisture/tar running down can seep through the joint and run down the outside of the metal flue.

 

Yes but this never happens if you burn dry wood vigorously as the  temperatures are above the dewpoint of the water vapour.

 

As I have posted before I am not using a steel liner as I utilise the fact that the chimney breast brickwork absorbs heat whilst firing and then the thermal mass gradually gives out heat overnight when the fire is out.

[Guest Gimlet]

The log burner in my mother's house has vitreous enamel pipe which runs through a poured in-situ pumice liner all the way up to the top of the stack. It has been been fitted with the sockets upside down because that's how the pipe they used happened to fit onto the spigot on top of the stove, so whoever fitted it continued with female-down all the way to the top. They should have started with male end down inside the spigot, and if that didn't fit use a double-ended female fitting to restore the flow to female-up before they got through the register plate (which they could easily have done because the stove sits in a huge inglenook and there's over six feet of stovepipe below the register plate).

 

Leaks occur during heavy rain in summer when the fire is not lit. Some rain water inevitably blows in under the cowl, runs down the pipe and leeches out of the joints and puddles on top of the stove. 

I think the problem is made worse because vitreous enamel liners have a smooth surface which water can run down readily in a straight line. With flexi-liners rain water has to track around the helical ridges which slow the descent so much it would probably never reaches the bottom anyway. 

Edited June 4, 2021 by Gimlet

[Guest Gimlet]

On 02/06/2021 at 21:41, Alycidon said:

We always use stainless, sometimes loose jobs because we are more costly but quality costs money,

 

A

I reckon a lot of builders/roofers who are asked to replace cowls when they're up there round a chimney stack anyway doing something else, use cheap and nasty ones from Screwfix or whatever they can find in Travis Perkins. I fitted a Screwfix one once as a subbie that the contractor had supplied and it was utter crap. Think it lasted about 12 months. The spot welds that attach the anchor straps to the cowl let go and the cowl ended up in the garden with the straps and the jubilee band still round the chimney pot. The mesh had already rusted out as well.

[1867_owl]

Hi folks. A couple people have said that they think my flue is concrete or clay. I've just cleaned off a section of it which looks pretty metallic to me. I tried a magnet on it (magnetic knife strip) which didn't attract. Any more thoughts on the material?