My 10-year old boiler (conventional, open flue) has started smelling
of gas when it fires up (and recently set my CO detector off). The
flue and ventillation are all fine. I've checked the input and burner
pressures and gas rate - all spot on.

The flames don't look too good - very yellow and look too big. All the
burners etc. have been properly serviced recently and this hasn't
fixed the problem.

regards,
Alan

"Alan" wrote in message
m...
My 10-year old boiler (conventional, open flue) has started smelling
of gas when it fires up (and recently set my CO detector off).

Make and model please?

The flue and ventillation are all fine. I've checked the input and burner
pressures and gas rate - all spot on.

On what basis do you state that the flue and the ventilation are all fine?


The flames don't look too good - very yellow and look too big. All the
burners etc. have been properly serviced recently and this hasn't
fixed the problem.

who carried out the service and what did it cover?



regards,
Alan

"John" wrote in message
...

"Alan" wrote in message
m...
My 10-year old boiler (conventional, open flue) has started smelling
of gas when it fires up (and recently set my CO detector off).

Make and model please?

The flue and ventillation are all fine. I've checked the input and burner
pressures and gas rate - all spot on.

On what basis do you state that the flue and the ventilation are all fine?


The flames don't look too good - very yellow and look too big. All the
burners etc. have been properly serviced recently and this hasn't
fixed the problem.

who carried out the service and what did it cover?



regards,
Alan



Oh and do not use it until this problem has been addressed

"John" wrote in message ...
"Alan" wrote in message
m...
My 10-year old boiler (conventional, open flue) has started smelling
of gas when it fires up (and recently set my CO detector off).

Make and model please?

The flue and ventillation are all fine. I've checked the input and burner
pressures and gas rate - all spot on.

On what basis do you state that the flue and the ventilation are all fine?


The flames don't look too good - very yellow and look too big. All the
burners etc. have been properly serviced recently and this hasn't
fixed the problem.

who carried out the service and what did it cover?



regards,
Alan

Well, the original technician who serviced the boiler, then condemed it
reckoned it needed a new burner assembly - "but the boiler was obsolete
so probably wasn't worth repairing". I tried to get some other opinions
- one plumber never returned my call, another said he could fit me in
3 days later, but he never turned up...

In the meantime, I found the service manual on-line, made myself a
manometer with a bit of plastic tube, dis-assembled the boiler to
check the lint arrestor and injector (all fine), did some smoke
tests with some smoldering kitchen roll and found the
heat exchanger still quite sooted (I know I said it was clear, but
I am no expert and the bloke who cleaned it a few days before was...)

Spent a while properly cleaning the heat exchanger, then tested for
leaks and inlet & burner pressure with the manometer and rechecked
gas usage - all seemed fine, the yellow flames have gone, the CO
detector stays off and the bad smell gone. So I peeled the
"Immediately Dangerous" sticker of my boiler.

So if you hear of a large explosion in the Manchester area...

regards,
Alan

Alan wrote in message ...
My 10-year old boiler (conventional, open flue) has started smelling
of gas when it fires up (and recently set my CO detector off). The
flue and ventillation are all fine. I've checked the input and burner
pressures and gas rate - all spot on.

The flames don't look too good - very yellow and look too big. All the
burners etc. have been properly serviced recently and this hasn't
fixed the problem.

regards,
Alan

Yellow flames indicate insufficient air flow either because the air inlet to
the burner is restricted in some way or the flue is not allowing all the
combustion gasses out. As your CO detector is triggering I would suspect the
latter.
Yellow flames means soot which could well helpblock the flue even more. Do
get this checked out before there are serious consequences.
In the short term you couldback off the gas flow until the flames turn blue
again. You will get less heat output but at least it should be safe.

Whoever checked the boiler over did not do a good job. Either get him back
or use another reputable one to inspect and report the first one to CORGI

On Sat, 11 Sep 2004 20:13:46 +0000, Bob Minchin wrote:


Alan wrote in message ...
My 10-year old boiler (conventional, open flue) has started smelling
of gas when it fires up (and recently set my CO detector off). The
flue and ventillation are all fine. I've checked the input and burner
pressures and gas rate - all spot on.

The flames don't look too good - very yellow and look too big. All the
burners etc. have been properly serviced recently and this hasn't
fixed the problem.

regards,
Alan

Yellow flames indicate insufficient air flow either because the air inlet to
the burner is restricted in some way or the flue is not allowing all the
combustion gasses out. As your CO detector is triggering I would suspect the
latter.
Yellow flames means soot which could well helpblock the flue even more. Do
get this checked out before there are serious consequences.
In the short term you could back off the gas flow until the flames turn blue
again. You will get less heat output but at least it should be safe.

Well the the correct approach is that you EITHER fix it properly: (blue
flames [1], gas pressure at correct setting, gas rate 90-105% of nominal,
flue clear and passes a flow test. ) OR you turn it off.


Whoever checked the boiler over did not do a good job. Either get him back
or use another reputable one to inspect and report the first one to
CORGI.

If the first guy is half decent he will be round pronto 'with tail down'
when you say you have yellow flames from a open flued appliance and the CO
alarm has gone off. There are no more lines of safety left, just
fortuitous ventilation, timing & luck.

TRANSCO will give you an opinion but will (nigh on certain) condemn the
appliance.
HTH

[1] If using a combustion analyser then I'd reckon on CO/CO2 0.003 say.
--
Ed Sirett - Property maintainer and registered gas fitter.
The FAQ for uk.diy is at 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

In message , Alan
writes
My 10-year old boiler (conventional, open flue) has started smelling
of gas when it fires up (and recently set my CO detector off). The
flue and ventillation are all fine. I've checked the input and burner
pressures and gas rate - all spot on.

The flames don't look too good - very yellow

= incomplete combustion = Carbon monoxide



and look too big. All the
burners etc. have been properly serviced recently and this hasn't
fixed the problem.

Poor air supply? Blocked flue ? crud on the burners?

get it serviced properly

--
geoff

"Alan" wrote in message
om...
My 10-year old boiler (conventional, open flue) has started smelling
of gas when it fires up (and recently set my CO detector off).

Make and model please?

Potterton Kingfisher MkII

The flue and ventillation are all fine. I've checked the input and burner
pressures and gas rate - all spot on.

On what basis do you state that the flue and the ventilation are all fine?

The flue has been smoke tested and draws well without leakage. Looking up
the flue, there are no blockages - you can clearly see the inside of the
terminal. The fins of the heat exchanger have been thoroughly cleaned and
again you can see clear through it.

The boiler is in a utility room on the ground floor with a suitable vent.
However, opening doors, windows etc. in the room or elsewhere in the house
has no effect. The vents on the boiler are clear and all the spacing
around the boiler is well in excess of the manufacturers specification.

The flames don't look too good - very yellow and look too big. All the
burners etc. have been properly serviced recently and this hasn't
fixed the problem.

who carried out the service and what did it cover?

A Corgi registered firm. Supposedly a full service. There are no deposits
on the burners. They also claim to have cleaned the insides of the burners
in accordance with the makers instructions. I've no reason to disbelieve
them.

I have no intention of tackling any of this work myself. What I want to avoid
is:

- paying another technician to do a full service, only for him to be "surprised"
when the problem still isn't cured.
- paying somebody to install a new air brick, then installing a new flue, only
for him to be "surprised" when the problem isn't cured.
- installing a new boiler simply because the problem can't be correctly
diagnosed.

On a related note, how should I expect a competent technician to set about
diagnosing this problem?

thank you for your responses,
Alan

On 12 Sep 2004 03:31:18 -0700, (Alan) wrote:



A Corgi registered firm. Supposedly a full service. There are no deposits
on the burners. They also claim to have cleaned the insides of the burners
in accordance with the makers instructions. I've no reason to disbelieve
them.

I have no intention of tackling any of this work myself. What I want to avoid
is:

- paying another technician to do a full service, only for him to be "surprised"
when the problem still isn't cured.
- paying somebody to install a new air brick, then installing a new flue, only
for him to be "surprised" when the problem isn't cured.
- installing a new boiler simply because the problem can't be correctly
diagnosed.

On a related note, how should I expect a competent technician to set about
diagnosing this problem?

thank you for your responses,
Alan

One obvious test would have been for the firm servicing the boiler to
have used a flue gas analyser to measure the CO , CO/CO2, and O2
levels.

This kind of analyser has a probe which goes into a special port in
the combustion chamber on some boilers or into the flue.
It would confirm the situation and give figures as to how bad it is.

Yellow flames are still a strong indicator that all is not well.

I don't believe that it is a mandatory requirement for a CORGI
engineer to have one of these, but considering that they start at
about £200, there is no reason that somebody servicing boilers should
not have one.

I would call back the firm that serviced the boiler, ask them to do
these measurements and provide the figures. Then contact the
manufacturer and ask them whether the results are satisfactory.

If they don't agree to this, then report them to CORGI and ask the
manufacturer for the name of an authorised engineer of theirs.





..andy

To email, substitute .nospam with .gl

In article ,
Andy Hall writes:

I don't believe that it is a mandatory requirement for a CORGI
engineer to have one of these, but considering that they start at
about £200, there is no reason that somebody servicing boilers should
not have one.

It can't be mandatory -- I couldn't find a CORGI gas fitter who had one
when running through them in the Yellow Pages. I mentioned this to
Keston (having just fitted my Keston at the time), and the chap I was
speaking to agreed that they mostly didn't.

--
Andrew Gabriel

On 12 Sep 2004 17:10:46 GMT, (Andrew
Gabriel) wrote:

In article ,
Andy Hall writes:

I don't believe that it is a mandatory requirement for a CORGI
engineer to have one of these, but considering that they start at
about £200, there is no reason that somebody servicing boilers should
not have one.

It can't be mandatory -- I couldn't find a CORGI gas fitter who had one
when running through them in the Yellow Pages. I mentioned this to
Keston (having just fitted my Keston at the time), and the chap I was
speaking to agreed that they mostly didn't.

Somewhat concerning in a way.

Quite a lot of the boilers coming onto the market, especially those
with premix burners, seem to have use of a combustion analyser in the
setup procedure - typically that the emission composition should be
checked at low and high end and the gas rate adjusted to match the air
supply from the fan at the given burn rate.

BG seem to have them, although this seems to be mainly so that they
can just check the flue with the probe and pronounce the boiler OK
without taking it apart.
..
One day's visits and they've paid for the analyser comfortably.


..andy

To email, substitute .nospam with .gl

On Sun, 12 Sep 2004 03:31:18 -0700, Alan wrote:

"Alan" wrote in message
. com...
My 10-year old boiler (conventional, open flue) has started smelling
of gas when it fires up (and recently set my CO detector off).

Make and model please?

Potterton Kingfisher MkII

The flue and ventillation are all fine. I've checked the input and burner
pressures and gas rate - all spot on.

On what basis do you state that the flue and the ventilation are all fine?

The flue has been smoke tested and draws well without leakage. Looking up
the flue, there are no blockages - you can clearly see the inside of the
terminal. The fins of the heat exchanger have been thoroughly cleaned and
again you can see clear through it.

The boiler is in a utility room on the ground floor with a suitable vent.
However, opening doors, windows etc. in the room or elsewhere in the house
has no effect. The vents on the boiler are clear and all the spacing
around the boiler is well in excess of the manufacturers specification.

The flames don't look too good - very yellow and look too big. All the
burners etc. have been properly serviced recently and this hasn't
fixed the problem.

who carried out the service and what did it cover?

A Corgi registered firm. Supposedly a full service. There are no deposits
on the burners. They also claim to have cleaned the insides of the burners
in accordance with the makers instructions. I've no reason to disbelieve
them.

I have no intention of tackling any of this work myself. What I want to avoid
is:

- paying another technician to do a full service, only for him to be "surprised"
when the problem still isn't cured.
- paying somebody to install a new air brick, then installing a new flue, only
for him to be "surprised" when the problem isn't cured.
- installing a new boiler simply because the problem can't be correctly
diagnosed.

On a related note, how should I expect a competent technician to set about
diagnosing this problem?

Since the pressure and gas rate are correct, the flue clear and opening a
door make no change the problem MUST lie between the injector(s) and the
burners. There are often gauzes in the mixing tube which can get blocked
with very fine dust.

More surprising is the CO alarm going off this implies the products of
cumbustion are not being correctly drawn into the flue which is odd since
it is apparently clear.

Anyway fixing (or even replacing) the burner should be the first approach
but the alarm makes me think there is another problem to be found.

--
Ed Sirett - Property maintainer and registered gas fitter.
The FAQ for uk.diy is at 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

Alan wrote:

The flue and ventillation are all fine. I've checked the input and burner
pressures and gas rate - all spot on.


On what basis do you state that the flue and the ventilation are all fine?


The flue has been smoke tested and draws well without leakage. Looking up
the flue, there are no blockages - you can clearly see the inside of the
terminal. The fins of the heat exchanger have been thoroughly cleaned and
again you can see clear through it.

The boiler is in a utility room on the ground floor with a suitable vent.
However, opening doors, windows etc. in the room or elsewhere in the house
has no effect. The vents on the boiler are clear and all the spacing
around the boiler is well in excess of the manufacturers specification.


The flames don't look too good - very yellow and look too big. All the
burners etc. have been properly serviced recently and this hasn't
fixed the problem.


who carried out the service and what did it cover?


A Corgi registered firm. Supposedly a full service. There are no deposits
on the burners. They also claim to have cleaned the insides of the burners
in accordance with the makers instructions. I've no reason to disbelieve
them.

I have no intention of tackling any of this work myself. What I want to avoid
is:

- paying another technician to do a full service, only for him to be "surprised"
when the problem still isn't cured.
- paying somebody to install a new air brick, then installing a new flue, only
for him to be "surprised" when the problem isn't cured.
- installing a new boiler simply because the problem can't be correctly
diagnosed.

On a related note, how should I expect a competent technician to set about
diagnosing this problem?

thank you for your responses,
Alan

Check the inlet side of the flue isn't blocked by leaves, birds nests,
vermin etc, anyone can get the burner to burn clean with the cover off,
but put it back on and you rely on the inlet. British gas never checked
mine and it went that way, pulled the flue from the wall and the inlet
was clogged with leaves....

On Sun, 12 Sep 2004 20:50:39 +0000, Badger wrote:



Alan wrote:

The flue and ventillation are all fine. I've checked the input and burner
pressures and gas rate - all spot on.


On what basis do you state that the flue and the ventilation are all fine?


The flue has been smoke tested and draws well without leakage. Looking up
the flue, there are no blockages - you can clearly see the inside of the
terminal. The fins of the heat exchanger have been thoroughly cleaned and
again you can see clear through it.

The boiler is in a utility room on the ground floor with a suitable vent.
However, opening doors, windows etc. in the room or elsewhere in the house
has no effect. The vents on the boiler are clear and all the spacing
around the boiler is well in excess of the manufacturers specification.


The flames don't look too good - very yellow and look too big. All the
burners etc. have been properly serviced recently and this hasn't
fixed the problem.


who carried out the service and what did it cover?


A Corgi registered firm. Supposedly a full service. There are no deposits
on the burners. They also claim to have cleaned the insides of the burners
in accordance with the makers instructions. I've no reason to disbelieve
them.

I have no intention of tackling any of this work myself. What I want to avoid
is:

- paying another technician to do a full service, only for him to be "surprised"
when the problem still isn't cured.
- paying somebody to install a new air brick, then installing a new flue, only
for him to be "surprised" when the problem isn't cured.
- installing a new boiler simply because the problem can't be correctly
diagnosed.

On a related note, how should I expect a competent technician to set about
diagnosing this problem?

thank you for your responses,
Alan

Check the inlet side of the flue isn't blocked by leaves, birds nests,
vermin etc, anyone can get the burner to burn clean with the cover off,
but put it back on and you rely on the inlet. British gas never checked
mine and it went that way, pulled the flue from the wall and the inlet
was clogged with leaves....

This is a conventional flue not a balanced or fan assisted flue/duct.


--
Ed Sirett - Property maintainer and registered gas fitter.
The FAQ for uk.diy is at 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

raden wrote:

Poor air supply? Blocked flue ? crud on the burners?

Blocked lint arrester? (Should have been cleaned as part of the service
of course.)

--
Andy