balanced flues

[Stephen]

Hello,

I was looking at Grant boilers and see that they can have either conventional flues or balanced flues. They do chimney lining kits but the balanced option is £600+ whereas the conventional flue version is £200+; that's a big difference. Is there any advantage to paying the extra for a balanced flue or would you go conventional?

I had a couple of quotes and the plumbers seem to favour the cheaper option.

I understand with conventional flues you have to be careful with extractor fans. The brochure says the fans have to be installed to BSxxxx. We have a fan and a cooker hood so what does BS xxxx involve? Where can I find and read it?

Thanks. Stephen.

[Ed Sirett]

Is this a gas, oil or solid fuel boiler?

[John]

My own (non-expert) opinion would be to go with a balanced flue. Over 20 years I have had problems with Corgi guys (and BG) challenging my ventilation. Standards may have changed since original installation and I had to bring in some extra ducting of air. Always an issue for me.

[Dave Plowman (News)]

I had a CORGI guy challenge the ventilation for my old room sealed boiler. He also reckoned it shouldn't be mounted on a wood floor as it was a fire risk. But it conformed in both ways to the maker's installation instructions. Basically, he was a con artist.

[Stephen]

Sorry I forgot to mention, it's oil, though I don't think Grant make any thing else. Does it make a difference? I've never quite understood how the air gets into the boiler "conventionally" considering the boiler is enclosed on all four sides with enamelled sheet metal, insulation, etc.

[Hugo Nebula]

I presume the xxxx part is a number. I suspect installing the fan to the BS is not the issue, except that it will probably tell you to look up something else (often the manufacturer's information) if there are any open-flued appliances in the vicinity.

The guidance in Approved Document J is, "For oil appliances: limit fan capacities as described in OFTEC Technical Information Note TI/112 and then carry out flue draught interference tests as described in TI/112". So a copy of that OFTEC note may be your best bet.

[Stephen]

But I think you need to be OFTEC registered to view their notes. Does anyone have a copy?

Thanks.