Multifuel Stove

Ronnie22_2

Man_Overboard wrote: »

The mixture of metric and imperial seems unnecessarily confusing, especially coming from someone as well-informed as yourself.

What makes you think that a 50% increase in flue diameter above the register plate will make any difference to the strength of the draw? If you were to use no liner at all, the increase would be even greater. But if you feel that a liner is necessary, then a register plate is completely redundant.

Are you worried that 8.5m is too short, or too long?

Metric Imperial reason - stoves are generally expressed by outlet size in inches, flue pipe is bought in meter lenghts. Old and new school meet in the middle.

I was concerned at the length of the flue, I have come across friends with open fires and chimneys that have not drawn to a sufficient amount i.e. smoke overlapping the fire place mantle head and coming into their rooms. Not sure whether this was due to a cold chimney, height of chimney, bad fireback design, of poor ventilation, etc. One of them still hasn't got to the bottim of their problem. However, the comments posted have addressed my concern.

A register plate will be fitted to my installation due to sign off requirements of the inspecting local authority or hetas engineer, and the Doc J requirements for one, plus convected stove heat stays in the room. For the sake of £30 and no mess at the falling down the chimney I feel it's a worth while investment, plus it stops her indoors giving me grief too.

However, your argument about not needing a register plate appears to me to be generally sound if the flue is terminated at a suspended cowl or above a top plate flue terminal, in which case there is a point of direct separation from the exhaust gas and inlet gas, except in the firebox or when the stove door is open, i.e. the chimney cannot act as a balanced flue duct and pull back some of the CO and CO2 Hydrocarbons etc into the room...

Personally, I would have thought the safest way of combustion would be via balanced flue (one pipe for inlet gas and one for the exhaust with full separation), but suitable sealing of the firebox then becomes a constant issue with all that door opening and shutting. Maybe that's one for the future.

hethmar

Hi, with an open fire that has smoke into the room (just as you describe, curling under the mantle ) its normally due to the opening area being too large for the flue diameter.

Often this could be cured by a (adjustable) hood which you can drop down should the atmospherics worsen the prob; or by reducing the opening area by making it smaller/shorter - experimenting with a bit of non combustible material will give the optimum area you have to play with - or by lifting up the dog grate - not just bunging a brick under each leg but actually blocking right across the base. An expensive alternative is to install a chimney fan on top of the stack but we have stopped doing these because of various reasons - they have to be on all the time the fire is working and in domestic circs this can have an annoying humming - other problem is that sweeps arent keen to climb up and clean fans and there was one well known restaurant who would ring us every couple of years having had a chimney fire due to a bunged up chimney fan. I take it your friend has got sufficient ventilation into the room and havent got tall trees round the house.

This is a problem which you wont get with your properly installed woodburner

Ronnie22_2

Sounds like my friend has a bit of all the above problems, I'll let him know what he can try.

But it sounds like the opening may well be too big for the chimney, and there are lots of tall trees about, ventilation shouldn't be a problem old victorian house with wooden floorboards.