flu diffusers

[migoplumber]

does anybody see a lot of these systems, quoted as type B12 in the viper book, Im after someone "neutral" giving me a reason for installing/maintaining this flu type. many thanks

 

[tamz]

This flue system is more common seen or I&C work.
These were only seen domestic on a very few older boilers. Vokera did one as did Glow Worm and a couple of others.
There was a council estate not far from me which in the 80's, had O/F Ideal W2000's fitted with a fan (Ideal supplied) done this way but flued to the side. Seemingly the council were talked into buying a few hundred O/F boilers on the cheap and Ideal supplied the fan attachments to suit.
Most if not all have now been replaced.
They are rarely encountered and you would have no real reason to fit one.
Combustion air is drawn directly from the room.

 

[migoplumber]

thanks for reply tamz,
my work is i & c and was looking for an answer along the lines of yes they are needed and for "this" reason. its clear in my head, but wanted somebody elses point of view !
ta again.

 

[tamz]

On I&C work they are used to dilute the CO2 content of the flue gas to below 1% and below 100ppm CO and mainly used when it is cheaper/easier than doing a high rise chimney. More often found as a B13 or 14 though.