balanced flue: worth it?

Hello,

Is it worth having a balanced flue? My boiler is in the kitchen next to the door, so I cannot have a low level flue because it would be within 600mm of the door. There is a chimney behind the boiler but the grant "red" balanced flexi flue kit costs £600 plus vat. OTOH their "orange" conventional flue kit costs just over £200: a third of the cost. Is there any reason I have to have a balanced flue? Could I stick with a conventional flue and save the cost?

There's already a 100mm steel flue in the chimney but the old boiler was non-condensing. Am I right that this would have to be replaced because the acidic condensate might attack the metal? If I went with a non-condensing boiler (see other post), could I get away with using the old flue?

Thanks, Stephen.

Reply to
Stephen
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One of us is misunderstanding something! A balanced flue is one where the appliance is sealed from its surroundings and the exhaust gases and the incoming air share the same flue concentrically. In this sense, yes, a balanced flue appliance is far better as there is no path for gas or flue gases to enter the inside of the building and affect the occupants. With a conventional flue, the air required is extracted from the room, requiring an open path between the room and the gas burner. I do not know of appliances where one can choose the two flues but would imagine a conversion to a balanced flue would be expensive!

Reply to
Bob Mannix

I'm probably wrong but I don't think you can buy a non balanced flue boiler anymore. The efficiency would be too low.

Reply to
Dave Plowman (News)

Hi Stephen, I'm curious to know where the 600mm-from-the-door rule comes from - see the thread on my own boiler situation.

Reply to
Martin Pentreath

Most, if not all, modern boilers will have a powered balanced flue. using the a coaxial flue/duct.

Often older boiler did have choices of flue type. Usually between conventional (= not room-sealed) and balanced.

Much of some of the question you may have is in the Boiler Choice FAQ.

Reply to
Ed Sirett

Maybe the OP was referring to an open flue (B23, no draught diverter, forced ventilation)? Like option E perhaps?

I would be interested when the time comes to replace my conventional flue gas boiler because of the difficulty in relocating it.

Are there any serious safety or other gotchas? Are B23 flue kits available from gas boiler manufacturers other than Halstead? (Grant make oil fired only)

MJA

Reply to
MJA

Hello, I was looking at the Grant condensing brochure (downloadable pdf from their web site). It says "all Grant boilers are supplied for connection to either a stainless steel conventional flue or one of Grants EZ_flue options."

I have the old boiler in the kitchen connected to a steel conventional flue up the chimney. To convert this to a balanced flue would require the Grant red flexi flue that would cost over £600 ex VAT, which seems horrendously expensive.

The other option is to line the chimney with their conventional orange flue kit at just over £200 ex vat. However, since the brochure mentions conventional steel flues, I am not quite sure why I can't use what I have got already? I thought the steel was attacked by the acid condensate?

Thanks, Stephen.

Reply to
Stephen

I just found this:

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" Open Flue: A chimney taking flue gases from an appliance which terminates in the open air, usually above roof level. Masonry chimneys must always be fitted with a flexible flue liner to prevent the gases coming into contact with the chimney itself. The liner needs to be replaced each time a boiler is fitted. An appliance connected to an open flue must be provided with a combustion air supply directly from the outside."

Why should a new boiler need a new flue?

Reply to
Stephen

I saw a diagram somewhere showing the distances the flue must be from various objects. Now I am looking for it I cannot find it. I'll post when I do. I thought it must be either the oftec site or a boiler manufacturer's website. Sorry I cannot be of more help at the moment.

Reply to
Stephen

The instructions for my Viessmann say 300 mm from an opening - even below a window.

Reply to
Dave Plowman (News)

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