In article .uk,
Ed Sirett writes
On Fri, 24 Dec 2004 02:24:18 -0800, Martyn Pollard wrote:

Has anyone seen the 'judder' starting issue with the C25? Don't know the
exact cause, but Keston have a retrofit that appears to cure it. If I
get a report of this noise I just refer it direct to Keston and they
send an engineer out.

Ah 'buzz bombing' as I call it.
AFAIK after consultation with their technical dept it is due to the burner
being slightly weak. You really need a combustion analyser to make sure
that the CO2 values are in spec at both the minimum and maximum rates.

Def seconded on that one (running weak). I set mine up using their timed
meter rate method (wot a joke) and as a result set it far too weak. I hired
an analyser (HSS do them) and once it was set up properly it hasn't been
a problem. Running weak also caused serious ignition problems.
--
fred