stove problems

[chade]

My mother has a couple of solid fuel stoves in her house. One is only used infrequently. How important is it to fit a weather guard of some kind to th e pot?

The other is lit most days over the winter. There is a sectional metal flue that rises from the top of the stove, through two angles, into the top of the alchove. Where it becomes brick. It goes through two more angles, acces sible through a hatch in the external wall. It becomes first a brick chimne y and then a lined chimney.

When lit at first the fire draws okay, however when it becomes hot it start s to struggle. Often going out completely. It does perform better on coal t han wood. It would be better if it could run on wood. The second problem is it can 'blow back' under certain conditions, such as a door being quickly closed or a extractor fan being run in the house.

The first thing I am going to try is sealing the joints between the metal f lue sections, starting with the join to the top of the stove. I see screwfi x lists pluma flue (66373) but that is only rated to 300C firestop (25153) is rated to 1200C but for ridgid seals. Is either suitable? There is an ins pection panel in the round metal flue before the wall. The seal was a felt like substance that has deteriorated, what would it be called?

Thanks

[harryagain]

The other is lit most days over the winter. There is a sectional metal flue that rises from the top of the stove, through two angles, into the top of the alchove. Where it becomes brick. It goes through two more angles, accessible through a hatch in the external wall. It becomes first a brick chimney and then a lined chimney.

When lit at first the fire draws okay, however when it becomes hot it starts to struggle. Often going out completely. It does perform better on coal than wood. It would be better if it could run on wood. The second problem is it can 'blow back' under certain conditions, such as a door being quickly closed or a extractor fan being run in the house.

The first thing I am going to try is sealing the joints between the metal flue sections, starting with the join to the top of the stove. I see screwfix lists pluma flue (66373) but that is only rated to 300C firestop (25153) is rated to 1200C but for ridgid seals. Is either suitable? There is an inspection panel in the round metal flue before the wall. The seal was a felt like substance that has deteriorated, what would it be called?

Thanks

It sounds to me that what is going on now has a killer potential for house inmates. (From combustion gas products) You would be best to get in an experienced heating engineer to sort out your chimney /ventilation problems Under no circumstances should you run the stove until all is sorted out.

First, your chimney needs attention, it likely needs a liner fitted. There needs to be proper ventilation, ie air has to enter the room in order for the chimney to function correctly. You need to get a Carbon Monoxide alarm,

[Nick Odell]

Absolutely endorse that.

You know, it's really not my habit To intrude Furthermore, I hope my meaning Won't be lost or misconstrued But I'll repeat myself At the risk of being crude There must be Fifty Ways to Kill Your Mother

Light up the Stove, Jove Slam shut the door, Paul Turn on the fan, Sam Just listen to me.

Block up the flu, Stu Build up CO, Joe Don't fit an alarm, ma'am And get yourself free.

Nick

[John Williamson]

When were the flues last swept? And have they got a bird guard on the top, as last time I had this problem, the sweep extracted a bin bag full of nest after the flue had been out of use for the Summer.

IME, if the flue is correctly designed and empty, then no matter how leaky it is, it will still draw well.

[meow2222]

d infrequently. How important is it to fit a weather guard of some kind to the pot?

ue that rises from the top of the stove, through two angles, into the top o f the alchove. Where it becomes brick. It goes through two more angles, acc essible through a hatch in the external wall. It becomes first a brick chim ney and then a lined chimney.

rts to struggle. Often going out completely. It does perform better on coal than wood. It would be better if it could run on wood. The second problem is it can 'blow back' under certain conditions, such as a door being quickl y closed or a extractor fan being run in the house.

flue sections, starting with the join to the top of the stove. I see screw fix lists pluma flue (66373) but that is only rated to 300C firestop (25153 ) is rated to 1200C but for ridgid seals. Is either suitable? There is an i nspection panel in the round metal flue before the wall. The seal was a fel t like substance that has deteriorated, what would it be called?

Modern accepted wisdom says its plainly dangerous. OTOH many of us grew up with similarish of setups, and just accepted it got a little smoky sometime s. IOW I dont know what the level of risk is, but these are conditions that will produce CO, and putting that into the house is surely a fool's game.

NT

[Dave Liquorice]

Reasonably but stopping birds (normally Jackdaws) nesting in it is also high up the list.

So it's not lined all the way up? Don't like that idea for the flue gas flow/temperature profile. Presumably the brick section has a larger cross section than the lined part(s)? the flow rate will drop and being brick cool the gases, making them denser. I sort of see this generating "cold plug" of flue gases in that section.

Not good, *possibly* caused by the inconsistent dia flue and construction, as above.

The rooms with the stoves should have some free air ventilation. Indeed stoves bigger than, I think, 5 kW *must* have suitable free air ventilation. IIRC a chimney/flu must still draw when all the extract fans in the property are on, internal doors open, etc.

The first thing you should be doing is sorting out the ventilation...

Personally I'd rather use a fire cement than a silicone. Cement will allow disassembly and clean up should that ever be required.

Flue gasket?

[newshound]

+1.

In the two (old) houses where I have had woodburners, the drafts have easily exceeded the modern ventilation requirement.

[chade]

She already has the two I have bought her previously. The mains one she kept switched off "to save power" and the battery one she took the batteries out of to "save" them as well.

[chade]

I can not give an exact answer as to when they were last swept but there are clear and seem clean. I know because i examined them with the aid of a torch (lowered down by a string in the case of the chimney).

[chade]

That chimney is currently capped by mesh. It does not keep out the weather but has defeated birds up until now.

The chimney was extended at one point when a second story was added to that section of the house. So the lined section of the chimney is the top third . However before it gets that far the gases must go from a metal flue, expo sed to the air in the room to the horizontal brick flue and then the bottom of the chimney. Would that cause the same effect?

The stoves are in different rooms. The occasional use one is large and has an external vent ending in a small hole in the floor (!) next to the stove' s intake.

The daily use one is much smaller.

The room has a small opening window which she opens when the stove is runni ng as it does perform a bit better with the window open rather than closed. She complains about drafts a lot and I do not think additional vents is so mething she would agree to. I have toyed with the idea of installing a exte rnal vent piping outside air directly into the stove somehow, or even elect rically pumping air from the room into the stove but I am not sure if eithe r would be realistic or effective.

Given flue and stove seem to be different metals I guess they would expand at different rates? Would cement be too rigid?

I have tried a quick google search with that term which threw up some rope like seals. This was a thick sheet that lay over the hole in the flue and w as trapped at the edges by the (oversized) hatch.

[Dave Liquorice]

Something to keep the worst out might be useful. Ours has something similar to this on it:

Horizontal, how far? Chimneys and flues are strange beasts when it come to how they draw (or not) but horizontal is never a good idea except for very short sections, think not much more than the size of the chimney/liner.

Probably even more so as the gases slow and cool in the horizontal section. But as I saw chimneys and flues are strange beasts. It also makes sweeping difficult.

ventilation...

Which really does point to inadequate ventilation.

You can get free air ventilators that are not supoosed to be drafty. They have a laberinth in the wall tube to make the path longer and convuluted.

Direct feed probably not that good on a stove not designed for it. I would need to form of flow control as well or you'd end up with a blast furnace. B-) IMHO anything to do with a stove has to be passive an work when power is abscent. No point in having a stove that can't safely be used with the power off, when are you going to really want to use it? Yep, when the power is off due to the ice storm raging outside...

Doesn't seem to be a problem on the joint between the top of our cast iron oil boiler and it's flue pipe.

It came back with "cut to size" 3 mm thick sheet/matting for me, along with the rope seals used for glass/doors,