I am still moaning. so do I only need 22mm gas pipe if I upgrade to a combi ? also, could I keep the original copper cylinder hot water storage tank if I do not have a combi ? thanks again.

John Claydon, May 2009

Chat about pipe sizes here - looks like 22mm if the boiler connection is 22mm Combi & Conventional both. All to do with possible pressure drop between meter & boiler and risk of incomplete combustion & Carbon Monoxide as far as I can tell.

http://www.detailingworld.co.uk/forum/archive/index.php/t-112680.html

Peccavi, May 2009

Combi ??? Why have a Combi ???

No stored hot water = no airing cupboard & no immersion heater to heat the water if the Combi fails. Baths take ages to fill especially in the winter. Combis are more complex, more expensive and fail more often. Cost more to install if changing from a conventional boiler.

They are cheaper to run though - I would guess a full 5% more efficient than a modern conventional boiler - You'll get the extra investment back in about 35 years.


If you drop the idea of a Combi you do get to keep your hot water tank. Some Combi chat here...

http://www.diyfaq.org.uk/plumbing/combi.html#intro

http://www.miketheboilerman.com/combis.htm

Ditch BG immediately.

Peccavi, May 2009