Over the last winter the boiler developed an inability to light as soon as
you switch it on. The switch clicks, the gas lights and immediately you see
the gas die down then go out. Then the whole process starts again. When it
was cold I counted it taking 50 attempts until it lit. It does light
eventually but it's getting worse as now it's having trouble sometimes when
it's been on for a while.

Now we've got the cash to have it fixed does anyone have an idea of what it
might be and how much it might cost? It's a Worcester 24i (if that helps
anyone).

Thanks,
Rich.

On 12 Apr, 15:00, Richard Kavanagh wrote:
Over the last winter the boiler developed an inability to light as soon as
you switch it on. The switch clicks, the gas lights and immediately you see
the gas die down then go out. Then the whole process starts again. When it
was cold I counted it taking 50 attempts until it lit. It does light
eventually but it's getting worse as now it's having trouble sometimes when
it's been on for a while.

Now we've got the cash to have it fixed does anyone have an idea of what it
might be and how much it might cost? It's a Worcester 24i (if that helps
anyone).

Thanks,
Rich.

Could it be that the flame detector is failing? It's a sensor which
tries to work out whether the gas has lit properly, and if it hasn't
turns it off until the boiler has another go at ignition.

On Mon, 12 Apr 2010 09:36:14 -0700 (PDT), Martin Pentreath said :

On 12 Apr, 15:00, Richard Kavanagh wrote:
[13 quoted lines suppressed]

Could it be that the flame detector is failing? It's a sensor which
tries to work out whether the gas has lit properly, and if it hasn't
turns it off until the boiler has another go at ignition.

That sounds exactly right thanks, I like to have an idea so that I can get
some decent quotes.

Cheers!
Rich.

In message , Richard Kavanagh
writes
On Mon, 12 Apr 2010 09:36:14 -0700 (PDT), Martin Pentreath said :

On 12 Apr, 15:00, Richard Kavanagh wrote:
[13 quoted lines suppressed]

Could it be that the flame detector is failing? It's a sensor which
tries to work out whether the gas has lit properly, and if it hasn't
turns it off until the boiler has another go at ignition.

That sounds exactly right thanks, I like to have an idea so that I can get
some decent quotes.

Flame sensing is performed on the pcb electronically, there is no sensor
as such, just an electrode which connects to the flame sensing circuit
on the board

The three things to check first are

1/ That the sensing electrode is actually in the flame

2/ that the flame sense lead from electrode (not the HT one) is intact

3/ that earthing is good and that you haven't done anything recently to
the electrics which might have swapped live and neutral over (I had a
case of this last week)

if all those check out, then barring some really strange fault, it has
to be the pcb - in which case, see my website www.cetltd.com



--
geoff

"Richard Kavanagh" wrote in message
. ..
Over the last winter the boiler developed an inability to light as soon as
you switch it on. The switch clicks, the gas lights and immediately you
see
the gas die down then go out. Then the whole process starts again. When it
was cold I counted it taking 50 attempts until it lit. It does light
eventually but it's getting worse as now it's having trouble sometimes
when
it's been on for a while.

Now we've got the cash to have it fixed does anyone have an idea of what
it
might be and how much it might cost? It's a Worcester 24i (if that helps
anyone).

Thanks,
Rich.

A very common question in diy fora.

Not a gas fitter you understand but, from what I have seen, the pilot gas
supply is held on by the expansion of a coiled tube of one metal with a
different metal inside it. The inner metal is held in the flame of the
pilot light while you hold your thumb on the bypass circuit button. As the
inner metal warms it expands and pushes the button on which it is bolted at
the other end, and holds the pilot gas on.

The end that sits in the flame is - to my mind - deliberately made of flimsy
stuff, and burns away gradually. This then turns off the pilot gas, which
then turns off the main gas. Clever: but usually packs up just when you
need it the most. On our old Baxi this would be about once a year. In
student days we learnt that there was a certain amount of adjustment that
could get the business end of a part burned sensor back in the pilot flame.
Later I found that the units only cost a few quid from any gas supplies
shop.

Now of course it would be highly illegal for any UKdiyer to go anywhere near
such a thing, but that is most likely what has happened to your device.

Here's some pics:
http://images.google.co.uk/images?q=...N&hl=en&tab=wi

(There's loads of stuff on how to replace them on the US diy sites...)

S

In message , spamlet
writes

"Richard Kavanagh" wrote in message
...
Over the last winter the boiler developed an inability to light as soon as
you switch it on. The switch clicks, the gas lights and immediately you
see
the gas die down then go out. Then the whole process starts again. When it
was cold I counted it taking 50 attempts until it lit. It does light
eventually but it's getting worse as now it's having trouble sometimes
when
it's been on for a while.

Now we've got the cash to have it fixed does anyone have an idea of what
it
might be and how much it might cost? It's a Worcester 24i (if that helps
anyone).

Thanks,
Rich.

A very common question in diy fora.

The following is totally wrong and should be ignored in its entirety



Not a gas fitter you understand but, from what I have seen, the pilot gas
supply is held on by the expansion of a coiled tube of one metal with a
different metal inside it. The inner metal is held in the flame of the
pilot light while you hold your thumb on the bypass circuit button. As the
inner metal warms it expands and pushes the button on which it is bolted at
the other end, and holds the pilot gas on.

The end that sits in the flame is - to my mind - deliberately made of flimsy
stuff, and burns away gradually. This then turns off the pilot gas, which
then turns off the main gas. Clever: but usually packs up just when you
need it the most. On our old Baxi this would be about once a year. In
student days we learnt that there was a certain amount of adjustment that
could get the business end of a part burned sensor back in the pilot flame.
Later I found that the units only cost a few quid from any gas supplies
shop.

Now of course it would be highly illegal for any UKdiyer to go anywhere near
such a thing, but that is most likely what has happened to your device.

Here's some pics:
http://images.google.co.uk/images?q=...rmocouple%22%2
0&oe=utf-8&rls=org.mozilla:en-GBfficial&client=firefox-a&um=1&ie=UTF-8
&sa=N&hl=en&tab=wi

(There's loads of stuff on how to replace them on the US diy sites...)

S



--
geoff

On Mon, 12 Apr 2010 23:45:05 +0100, geoff said :

In message , Richard Kavanagh
writes
[12 quoted lines suppressed]
Flame sensing is performed on the pcb electronically, there is no sensor
as such, just an electrode which connects to the flame sensing circuit
on the board

The three things to check first are

1/ That the sensing electrode is actually in the flame

2/ that the flame sense lead from electrode (not the HT one) is intact

3/ that earthing is good and that you haven't done anything recently to
the electrics which might have swapped live and neutral over (I had a
case of this last week)

if all those check out, then barring some really strange fault, it has
to be the pcb - in which case, see my website www.cetltd.com

Thanks for the advice.