On Wed, 24 May 2006 01:22:36 +0100, worriedconsumer wrote:
I bought a new Keston C25 boilers which was installed and commissioned
in late December 05. The installation was inspected in January 2006 by
a Keston engineer, and the boiler has been running well for the last
four months, but more recently it appeared to be losing efficiency.
This evening I noticed a dark stain in the grouting in the tilework
fronting the room space space in which the boiler was installed. I
investigated and found that condensate had been dripping out of the
boiler casing for what was clearly some time, judging by the highly
evident level of corrosion to the flow control valves, pipe work,
boiler casing and damage to the room space area beneath the boiler.
I am an engineer by trade, so I felt confident in investigating
further. I removed the casing to find condensate dripping out of the
fluted rubber vent tube to the right hand side of the combustion
chamber. There was also a pool of rusty-coloured liquid in the bottom
of the boiler which spilled out when I pulled back the casing.
I investigated further and found the rubber flue tube to be completely
corroded and brittle - the inner sides of the flutes have split so it
is possible to stretch the pipe out like a slinky spring. I ran the
boiler with the casing open and was shocked to see a huge amount of
flue gas coming back into the boiler itself. The boiler casing is
corroded in parts and very rusty looking, yet it is not even six months
old. It - not surprisingly - runs very hot, too.
The boiler casing is not properly sealed, either. A quick check with a
smoke can showed that the positive pressure of the flue gas was pushing
the flue gas out of the casing into the room cavity in which the boiler
is installed. This boiler room space is not vented to the outside - my
installer informed me that the boiler is self-venting, allowing it to
be installed in domestic spaces such as kitchen cupboards etc.
It is obviously a known design fault. I note - with a little bit of
investigation on the internet, including posts in this thread
describing a cracked 'gasket pipe' from January '05 - that the latest
version of the C25 boilers no longer contains this rubber pipe and has
been redesigned with a solid one. This can only be because someone
realised there was a serious problem.
My conclusion is that the model of boiler I have had installed is
actually dangerous. Keston has shipped boilers of this design for
nearly a year so there must be a lot of them out there. I have
contacted Keston to inform them of my findings. And I have informed
Corgi. I will post their response to this forum when I get it.
Richard Wrote:
The Keston system kit (expansion tank) failed- the membrane went and now
the cabinet overheats
Richard
My own is a 2003 model and has not had a problem in this area.
I installed one the other week and this has a thicker solid
un-reinforced one piece rubber hose from the bottom of the heat exchanger
to the flue outlet spigot. It makes a slight deviation around the gas
supply pipe.
When in operation with the cover on the internal air pressure is always
less than ambient (although severe weather could alter this on a very
temporary basis). This would be true even if the flue outlet hose splits
within the boiler casing (a bad fault). As AG posted if it got so bad that
there was a serious problem the boiler would shutdown.
The only condition which would make the outlet hose get subject to an over
temperature would be running the boiler with no water in it (there is a
low pressure cut out against this).
I agree that this is a real bummer but you should be able to get the
replacement part fitted by Keston under warranty.
--
Ed Sirett - Property maintainer and registered gas fitter.
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