Good point, David.
Boiler was installed in c.2000 and has always been fine, with the exception
of the stated replacement of the pcb which would have been probably 4 years
ago. No plumbing circuit changes, nothing different at all. The boiler is
the only gas appliance.
It's not until very recently that we've turned the CH on; it's possible that
the DHW problems described started around that time. Since we noticed a
problem c. two weeks ago it's got more pronounced.
Cold mains pressure is very good.
Thanks

Hi
Hoping for wise words in diagnosing the problem with my Alpha 240E combi
boiler.
Supply to the CH seems fine, in that those radiators which are not locally
thermostatically controlled are getting warm.
The problem is with the domestic hot water. Looking at the boiler when a
tap is turned on, the progress is;
- run a tap
- boiler detects the water demand and fires the burners
- water at the tap starts to flow warm
- after perhaps 20s (variable), burners cut out (no warning/ indicator
lights first)
- after another short delay, the burners usually cut in again
At the start of the week, it was possible to get a constant burn for DHW to
a downstairs tap by asking for quite a strong flow, i.e. tap nearly full on.
At lower flow rates it would burn-cycle. Now even that is gone; the water
isn't getting hot regardless of the flow requested.
Flow to the bathroom upstairs is now hopeless. Not only is the flow rate
much reduced from "normal", it barely gets above lukewarm such is the burn
cycling problem.
I've had my local CH technician out - the boiler was serviced, and he's had
the heat exchanger off to check for scale etc. - very clean.
I phoned Alpha and asked for a Service Manual. They readily agreed and an
envelope arrived yesterday - unfortunately just a user guide which tells me
nothing much beyond the fact that is uses gas to heat water. Certainly no
use for diagnostics.
I recall that we've had to replace the/ a PCB a few years ago, at 120GBP or
so. But presumably the failure could be of a thermostat, or the divertor
valve? Simple diagnostic steps anyone?
Thanks
Kingsley

On Fri, 20 Oct 2006 14:00:39 +0100 someone who may be "Kingsley
Sawyers" wrote this:-

Hoping for wise words in diagnosing the problem with my Alpha 240E combi
boiler.

Combination boilers are not much good at heating water, other then
in specific conditions.

I recall that we've had to replace the/ a PCB a few years ago, at 120GBP or
so. But presumably the failure could be of a thermostat, or the divertor
valve? Simple diagnostic steps anyone?

You neglected to say whether this is something which has always been
a problem, developed suddenly, has slowly been getting worse or
whether the plumbing has been changed. That might help those who
diagnose these contraptions to get closer to the cause.


--
David Hansen, Edinburgh
I will *always* explain revoked encryption keys, unless RIP prevents me
http://www.opsi.gov.uk/acts/acts2000/00023--e.htm#54

On Fri, 20 Oct 2006 14:00:39 +0100, Kingsley Sawyers wrote:

Hi
Hoping for wise words in diagnosing the problem with my Alpha 240E combi
boiler.
Supply to the CH seems fine, in that those radiators which are not locally
thermostatically controlled are getting warm.
The problem is with the domestic hot water. Looking at the boiler when a
tap is turned on, the progress is;
- run a tap
- boiler detects the water demand and fires the burners
- water at the tap starts to flow warm
- after perhaps 20s (variable), burners cut out (no warning/ indicator
lights first)
- after another short delay, the burners usually cut in again
At the start of the week, it was possible to get a constant burn for DHW to
a downstairs tap by asking for quite a strong flow, i.e. tap nearly full on.
At lower flow rates it would burn-cycle. Now even that is gone; the water
isn't getting hot regardless of the flow requested.
Flow to the bathroom upstairs is now hopeless. Not only is the flow rate
much reduced from "normal", it barely gets above lukewarm such is the burn
cycling problem.
I've had my local CH technician out - the boiler was serviced, and he's had
the heat exchanger off to check for scale etc. - very clean.

....um ... this is where I want to ask some awkward questions.

There can be no scale near the inlet and outlet whilst deep inside between
the plates there is trouble.

--
Ed Sirett - Property maintainer and registered gas fitter.
The FAQ for uk.diy is at http://www.diyfaq.org.uk
Gas fitting FAQ http://www.makewrite.demon.co.uk/GasFitting.html
Sealed CH FAQ http://www.makewrite.demon.co.uk/SealedCH.html
Choosing a Boiler FAQ http://www.makewrite.demon.co.uk/BoilerChoice.html
Gas Fitting Standards Docs he http://www.makewrite.demon.co.uk/GasFittingStandards

"Kingsley Sawyers" wrote in message
o.uk...
Hi
..
I phoned Alpha and asked for a Service Manual. They readily agreed and an
envelope arrived yesterday - unfortunately just a user guide which tells
me nothing much beyond the fact that is uses gas to heat water. Certainly
no use for diagnostics.

Go to www.alpha-boilers.com and drill down to your particular boiler, where
you'll find a "Download" tab for both user manuals and installation/service
manuals to download in .pdf format.

John.