In message .com, Ian
H writes
I have an 25yr old boiler and will upgrade to a new one before I have
to get a condensing variety.

Sorry, but you're almost a year too late

I understand that modern boilers have much
lower flue gas temperatures, and the current flue is 4inch cast iron up
to a soot door (which is about 8ft above the boiler room floor) in a
brick chimney which is lined with glazed pipe. There is no chimney
terminal.


--
geoff