"John" wrote in message
news:6w8Rn.42970$4w7.20324@hurricane...
I am about to have a new Combi fitted (Worcester Bosch 30cdi).

Never having CH before in 60 years, I did the same thing plus 10 rads. Now I
know why I steered clear, far too expensive to run, but I have it cracked,
only use 2 rads and have the stat mobile. Another thing I wouldn't have done
is have a 42" plasma, too expensive to run. £100 a month for gas & leccy?
Stuff that, I'm happy to stay a tightarse.


The installer and I cannot see the existing gas pipe to the current
Worcester Highflow Heatslave so are not sure if it is 22mm or smaller.
(obviously we will see it when the boiler is removed)

A neighbour in the same type of house found when his Heatslave was
replaced that the pipe was only 15mm and had to have a new (ugly external)
22 pipe run installed. This neighbour never had much success with his
Heatslave - but mine has always performed well and has been inspected
every year by B Gas.

I told the installer I was concerned that the pipe could be 15mm so he
offered to perform some sort of drop check. He took a reading at the meter
with a manometer with the gas cooker and boiler running - he then repeated
the test at the boiler and phoned Worcester Bosch. They confirmed that the
pressure was acceptable. I think the drop was 2 milli-bar. (from 21 down
to 19)

I realise there is some risk and uncertainly and that I may have to run a
new 22mm pipe - but what do you think. Does the 'evidence' point to the
hidden pipe being 22mm - or is this irrelevant because the pressure is
okay?

Do you think the installers approach is reasonable?