chimney liner All manner of questions and solutions to problems and issues surrounding the subject of brickwork, blockwork and stonework

[madworld]

hi,
installing a multi fuel stove, the chimney is already clay lined so my question is.Should a suitable flexible liner still be used with a back fill of insulation or will the clay lined chimney suffice.

many thanks.

[stoneyboy]

madworld,
If its lined and OK after a smoke test don't waste your money on adding another liner. The only down side may be that if you are using the stove on a low setting the combustion gases will condense in the chimney. Every time you use the stove get it well and hot and then restrict it back down to the level you want.
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[madworld]

many thanks, that was my concern as well (the condensing gases) and their effects in the long term also didn't want to go to all the expense of installing a liner if it wasn't necessary. Can hopefully press on now. thanks again.

[madworld]

hello again,
have now made the frame for the register plate and ready to connect the flue pipe to the top of the stove, wondering now if there is a minimum or maximum length of stove pipe that i should have from the stove outlet going up the chimney, was intending to make it as long as possible and in my estimation that would be between 1250mm at the least and 2000mm at the most but does it matter? Will having a longer stove pipe give a better draw or will it create some problems?
many thanks again.

[stoneyboy]

madworld,
Length of stove pipe should not made any difference but make sure it sticks out clear of the register plate and the diameter is at least 125mm. Its also worth having a sealable trap in the register plate for sweeping and removal of debris.
With that length of pipe you could also include a damper which will improve overall control of the stove.
Also try to fit an access door section in the stove pipe for cleaning, this will be in addition to access through the stove by removal of the internal baffle plate.
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[madworld]

many thanks stoeyboy,
the stove i am installing has a 5" flue pipe going into a 9" diameter chimney, the register plate is going to have 2 x 6" access panels either side of the flue pipe for cleaning out debris etc and the stove pipe i will get with an access door in the front, but i'm a little confused with the position of the damper i.e does it fit on top of/in the 5" flue pipe or is it positioned above the flue pipe in the chimney itself somewhere.
thanks again for taking the time to answer.

[stoneyboy]

madworld,
Fit the damper towards the top of the flue pipe well away from the stove, this should reduce the chances of it getting heavily coated with combustion solids.
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[madworld]

Hi again, going to have between 16" and 18" of pipe showing above the stove before it disappears through the register plate.Will this distance be sufficient to position the damper or should it be higher up i.e. is there a minimum distance above the stove that the damper should be fitted to reduce the build up of combustion solids? many thanks

[stoneyboy]

madworld,
In most cases there is little option because of the fireplace opening height, fit the damper as high as is practical.
In my experience fires burning coal products for prolonged periods on a low setting will coke up first on the lower part of the stove pipe. Fit the sealed access door just above the stove for quick access to check the pipe.
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