Why would a gas boiler make soot?
Nick
Conventional fully pumped vented system.
Installed and serviced annually by the same engineer.
Through the winter it had a problem. Heat output considerably down, making
soot and noxious fumes. Boiler is located in a well vented external boiler
room.
Engineer came out and diagnosed the gas control valve as being worn out.
Next visit he serviced the boiler, de-coked the heat exchanger, dismantled
and cleaned the flue, fitted and adjusted the new gas valve. Left in working
order.
The boiler is certainly running much better. Good blue flame and somewhat
quieter. Water output temp has risen gradually and continues to rise.
Problem is that it is still making soot in appreciable quantities. Flakes up
to about 10mm across.
Have spoken to the engineer again and he is a bit stumped.
My only guesses are (1) the boiler is now working more efficiently and is
burning off residue from the H/E or (2) that the burner unit is worn,
burning improperly, and creating soot.
If (1) I hope the problem will go away, but it has now been 3 months.
Any ideas please?
Nick.
Roger Mills
Soot usually comes from a yellow flame when there's not enough air to
burn the gas fully - but you say the flame is blue?
--
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Roger
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The Natural Philosopher
I know nothing about gas boilers, but a lot about fires,,and you are
right,,soot is bad combustion and the soot particles glow yellow hot and
that's what makes the flames yellow.
So it sounds as it the other theory - that its simply burning old shit
out - is the right one. You should see what comes out of a chimney if
you set one on fire. LOTS of soot!
The last guy to service my (oil) boiler had some sort of gas
analyser..presumably that's true of yer gas man, so if the combustion is
within spec, that's all you need to worry aboput..ultimately the soot
will burn away I guess.
harry
There should be very little soot. Soot is unburned fuel soyou are
losing money.
The usual cause is not enough air or the air and fuel are not being
properly mixed.
There could well be carbon monoxide in the flues gases (poisonous) so
this needs to be attended to right away.
The burner/flame spreader/gas jet needs to be checked for damage/
blockage.
The heat exchanger needs to be checked for blockage and corrosion.
The gas pressure needs to be checked first, if it is low the gas and
fuel may not be mixing correctly.
Next the flue gases need to be analysed.The tool for this is an oxygen
analyser (there should be a percentage of excess air in the gas).
This set to the maker's reccomendations.
geoff
<19c564a5-8274-4aae...@p6g2000vbn.googlegroups.com>,
harry <harol...@aol.com> writes
Aah - the gas / fuel mixture
No chance of any carbon monoxide there
>
>Next the flue gases need to be analysed.The tool for this is an oxygen
>analyser (there should be a percentage of excess air in the gas).
>This set to the maker's reccomendations.
Dennis morphs to drivel, Harry morphs to dennis
--
geoff
Gib Bogle
>> The gas pressure needs to be checked first, if it is low the gas and
>> fuel may not be mixing correctly.
>
> Aah - the gas / fuel mixture
>
> No chance of any carbon monoxide there
Just from first principles (no specific knowledge):
soot implies incomplete combustion
incomplete combustion can give CO
e.g. 4CH4 + 6O2 -> C + 2CO + CO2 + 8H2O
geoff
<g.b...@auckland.ac.nz> writes
It would if it was a gas / air mixture ...
Which is why they use a CO/CO2 meter, a Telegan for example
not really come across an oxygen meter in general use for measuring
combustion efficiency
--
geoff
harry
> In message <iod2ih$e3...@speranza.aioe.org>, Gib Bogle
> <g.bo...@auckland.ac.nz> writes
>
> - Show quoted text -
Co2 meters were used in days of yore for measuring purely carbon
fuels ie coal.
As there is much less carbon in gas, they are much less accurate which
is why oxygen analysers came in and are preferable.
Gib Bogle
> In message <iod2ih$e3f$1...@speranza.aioe.org>, Gib Bogle
> <g.b...@auckland.ac.nz> writes
>> On 4/17/2011 8:40 AM, geoff wrote:
>>
>>>> The gas pressure needs to be checked first, if it is low the gas and
>>>> fuel may not be mixing correctly.
>>>
>>> Aah - the gas / fuel mixture
>>>
>>> No chance of any carbon monoxide there
>>
>> Just from first principles (no specific knowledge):
>>
>> soot implies incomplete combustion
>>
>> incomplete combustion can give CO
>
>>
>> e.g. 4CH4 + 6O2 -> C + 2CO + CO2 + 8H2O
>
>
> It would if it was a gas / air mixture ...
Missed that.
geoff
<7235d047-1475-48da...@m7g2000vbq.googlegroups.com>,
harry <harol...@aol.com> writes
>On Apr 16, 11:23 pm, geoff <tr...@uk-diy.org> wrote:
>> In message <iod2ih$e3...@speranza.aioe.org>, Gib Bogle
>> <g.bo...@auckland.ac.nz> writes
>>
>>
>>
>>
>>
>> >On 4/17/2011 8:40 AM, geoff wrote:
>>
>> >>> The gas pressure needs to be checked first, if it is low the gas and
>> >>> fuel may not be mixing correctly.
>>
>> >> Aah - the gas / fuel mixture
>>
>> >> No chance of any carbon monoxide there
>>
>> >Just from first principles (no specific knowledge):
>>
>> >soot implies incomplete combustion
>>
>> >incomplete combustion can give CO
>>
>> >e.g. 4CH4 + 6O2 -> C + 2CO + CO2 + 8H2O
>>
>> It would if it was a gas / air mixture ...
>>
>> Which is why they use a CO/CO2 meter, a Telegan for example
>>
>> not really come across an oxygen meter in general use for measuring
>> combustion efficiency
>>
>> --
>> geoff- Hide quoted text -
>>
>> - Show quoted text -
>
>Co2 meters were used in days of yore for measuring purely carbon
>fuels ie coal.
No - co / co2 meters - measuring the ratio
>As there is much less carbon in gas,
Would you like to expand on that ?
Do you really understand what you're talking about?
>they are much less accurate which
>is why oxygen analysers came in and are preferable.
Not amongst your average jobbin' fitter they aren't
--
geoff
YAPH
> Problem is that it is still making soot in appreciable quantities.
> Flakes up to about 10mm across.
> Have spoken to the engineer again and he is a bit stumped.
>
> My only guesses are (1) the boiler is now working more efficiently and
> is burning off residue from the H/E or (2) that the burner unit is worn,
> burning improperly, and creating soot.
>
> If (1) I hope the problem will go away, but it has now been 3 months.
>
> Any ideas please?
Soot is a warning sign of incomplete combustion and your warning sign
that the boiler is probably producing carbon monoxide in lethal
quantities. If you had a large dog foaming at the mouth would you leave
it and hope the problem would go away?
Get it sorted.
Now.
Call 0800 111 999 and tell them about it.
--
John Stumbles -- http://yaph.co.uk
How odd of God But not so odd as those who choose
To choose the Jews A Jewish god, yet spurn the Jews
GB
>
>> As there is much less carbon in gas,
>
> Would you like to expand on that ?
Natural gas is mostly methane, ie CH4. My recollection is that the older
town gas used to include some longer chain hydrocarbons (which have a lower
carbon/hydrogen ratio than methane) as well as a fair amount of CO, which of
course has no hydrogen at all.
geoff
<NOTso...@microsoft.com> writes
I was trying to get at what harry thought was the relevance when it came
to using a co / co2 meter
--
geoff
GB
> I think we all know that
Now I'm totally deflated.
cynic
The heat exchanger is difficult to clean thoroughly and it is quite
possible that there is still trapped carbon but after 3 months you
have more than a residual problem.
Is the burner completely clean and properly jointed so that the flame
bed is entirely satisfactory without any patches of yellow sooty flame
across it? Does the burner gas pressure match with the data plate
information? has the heat exchanger been THOROUGHLY cleaned so all the
fins snd surfaces are clear of residual soot? Is the collector hood
and flue clear of soot?
I have seen a particularly badly sooted heat exchanger cleaned with a
pressure washer but as you can imagine that made a serious mess!
Steve Walker
> On Sat, 16 Apr 2011 13:29:36 +0100, Nick wrote:
>
>
>> Problem is that it is still making soot in appreciable quantities.
>> Flakes up to about 10mm across.
>> Have spoken to the engineer again and he is a bit stumped.
>>
>> My only guesses are (1) the boiler is now working more efficiently and
>> is burning off residue from the H/E or (2) that the burner unit is worn,
>> burning improperly, and creating soot.
>>
>> If (1) I hope the problem will go away, but it has now been 3 months.
>>
>> Any ideas please?
>
>
> Soot is a warning sign of incomplete combustion and your warning sign
> that the boiler is probably producing carbon monoxide in lethal
> quantities. If you had a large dog foaming at the mouth would you leave
> it and hope the problem would go away?
> Get it sorted.
> Now.
> Call 0800 111 999 and tell them about it.
I don't know about this particular boiler, but I've often wondered
whether there is any great risk to poor combustion with most boilers
these days, as they are generally room sealed and under negative
pressure due to the exhaust fan, therefore they should be unable to leak
CO into the room.
I would have thought that the main worry would be increased fuel bills
and gradually reducing heat output.
SteveW
tony sayer
<g.b...@auckland.ac.nz> scribeth thus
Bit worrying that, never seen soot from our boiler and If I did I'd soon
shut the thing down..
Mind you it can do that sometimes 'tho is been well behaved since it had
a new board from Geoff no surprise there needing one after all it's a
Suprima;!...
--
Tony Sayer
YAPH
> I don't know about this particular boiler, but I've often wondered
> whether there is any great risk to poor combustion with most boilers
> these days, as they are generally room sealed and under negative
> pressure due to the exhaust fan, therefore they should be unable to leak
> CO into the room.
It's not as dangerous as with a non-room-sealed type but it's still
putting CO into the atmosphere outside which can - given
prevailing wind conditions - get back into the house. Or a neighbours'
house.
There was a case recently where a boiler had been installed with its flue
close to a window, which had been screwed shut to prevent Products Of
Combustion (POCs in the trade) getting into the room. Then the owner of
the building had the window replaced, with one which had normal openers,
and the occupant of the room died of CO poisoning. (IIRC the boiler was
also badly malfunctioning - you wouldn't expect it of a normally-
operating boiler.)
And, more innocuously, I got called out a few months ago, when it was
freezing cold, to a house where a CO alarm in a room with a boiler had
gone off. The boiler seemed fine - burning cleanly (as measured on the
Flue Gas Analyser, and visual inspection - certainly no sign of sooting).
It was an upstairs room. No sign of any way gases from the cooker
downstairs could have got up to trigger the alarm. But the CO alarm was
next to a vent to outside, and I can only think that a car had been
idling outside for a while, with the engine running to warming up/keep
warm while waiting for someone, and the exhaust gases drifted up in the
cold still air and found there way in through the vent to the alarm.
--
John Stumbles -- http://yaph.co.uk
87.5% of statistics are made up
geoff
writes
>On Sun, 17 Apr 2011 22:07:46 +0100, Steve Walker wrote:
>
>> I don't know about this particular boiler, but I've often wondered
>> whether there is any great risk to poor combustion with most boilers
>> these days, as they are generally room sealed and under negative
>> pressure due to the exhaust fan, therefore they should be unable to leak
>> CO into the room.
>
>It's not as dangerous as with a non-room-sealed type but it's still
>putting CO into the atmosphere outside which can - given
>prevailing wind conditions - get back into the house. Or a neighbours'
>house.
>
--
geoff
Andrew Gabriel
My flue gas analyser has an oxygen cell and a CO cell.
CO2 is calculated from the oxygen content, knowing that
it's measuring natural gas flue gasses (I think you can
also set it for propane and butane, but I never have).
Mine doesn't calculate the CO/CO2 ratio - you have to do
that yourself, but the next model up does that for you,
for those who don't know how to convert units and do a
division;-).
I don't know what the situation is nowadays, but gas installers
didn't generally have flue gas analysers a few years back.
I bought mine when I installed my condensing boiler 10 years
ago, as although it was supposed to come pre-adjusted, it was
actually miles off the right settings, and it made a significant
difference getting it setup correctly.
--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]
Andy Champ
>
> I don't know about this particular boiler, but I've often wondered
> whether there is any great risk to poor combustion with most boilers
> these days, as they are generally room sealed and under negative
> pressure due to the exhaust fan, therefore they should be unable to leak
> CO into the room.
>
> I would have thought that the main worry would be increased fuel bills
> and gradually reducing heat output.
>
Just FYI mine's under positive pressure from an inlet fan. But the
combustion chamber is completely enclosed by the fresh air plenum except
the exhaust - so leaks would be cold fresh air into the room, anything
combusted can only go out of the flue.
Andy
jason.arth...@gmail.com
Second of all there is no guarantee that the “speeder jets” are blocked because there is a hundred different styles of burners. They all don’t have spreader jets.
As a 20 industrial boiler technician I’ll say soot usually comes from
- poor combustion air/ or a negative pressure in the room that the boiler sits in
- a dirty of damaged burner. (Most new residential high efficiency boilers use a mesh grill, so it’s probably not damaged.
- newer high efficiency boiler use zero governing gas valves. These valves mix the air and gas. So a faulty one of these would cause your boiler to soot up for sure(I think your engineer fixed the problem)
Last but not least, if the flame is blue, I doubt you’re still sooting. However the boiler more than likely modulates and the flame could be blue at %75 but yellow at %10 so you really need to check the flame in %10 increments
gopalan...@gmail.com
Free commentators pls refrain from speculation on deadly stuff like CO!
danny
--
For full context, visit https://www.homeownershub.com/uk-diy/why-would-a-gas-boiler-make-soot-700709-.htm
Rod Speed
<032f4712591ce8d6...@example.com> wrote:
> Not true. Lack of make up air can cause issues with incomplete
> combustion and high carbon monoxide levels. Gases can't vent out if
> there's no air to replace them
Peeler
Speed, the auto-contradicting senile sociopath, blabbered, again:
<FLUSH the abnormal trolling senile cretin's latest trollshit unread>
--
Sqwertz to Rodent Speed:
"This is just a hunch, but I'm betting you're kinda an argumentative
asshole.
MID: <ev1p6ml7ywd5$.d...@sqwertz.com>
Fredxx
> Not true. Lack of make up air can cause issues with incomplete
> combustion and high carbon monoxide levels. Gases can't vent out if
> there's no air to replace them
https://tinyurl.com/3m2hbkpy
when replying to a 10 year old thread to a boiler that's already 15
years old.
Brian Gaff (Sofa)
Brian
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Brian Gaff (Sofa)
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