In message
,
harry writes
On Nov 11, 5:14*pm, geoff wrote:
In message ,
writes

On Sun, 11 Nov 2012 08:31:38 -0800 (PST), harry
wrote:

The fan in most gas gas boilers is working on a mixture of gas and
air.

I don't follow that, I though it was just an induced draught fan after
the heat exchanger?

As usual Harry's confusing things

In most conventional boilers, the fan works on the air or the exhaust
gasses, in modern condensing boilers, quite often, the fan is blowing
premixed air/gas into the combustion chamber

--
geoff

I think that's what I said. Whether it's condensing or not is neither
here nor there.


No its not what you said

Some fans do premix the gas and air and they are getting increasingly
common, they are still in the minority. Most fans are on the exhaust
side of the boiler, venting the products of combustion, some blow air
into the boiler - (positive pressure, not so good) NOT a mixture of gas
and air. If you don't understand the difference, then STFU.


--
geoff