Baxi Barcelona, under service contract - in May this year started giving
intermittent €˜explosive ignition €¦ when it happens gives a seriously
loud bang
This boiler had been upgraded to 100HE spec some years gao.

Multiple visits and loads of parts €¦ fault just got worse €“ was also now
failing to ignite and going into Lock out .. every couple of days.
Another load of parts €¦ including upgrading the burner door so new style
1 piece electrode assembly could be fitted. (and replaced several times)

After multiple no -improvement visits €“ one engineer found electrodes
shorting to Air Box door panel €¦ I supplied him with high temp sleeving
€¦. Stopped shorting but still locking out.

After about a dozen visits one Tech noticed that every time it failed to
ignite he could see a flash over on back of ignition board €¦ multiple
board changes, individually and as a pair with control board.
Lockout frequency increased to every start cycle €“ so boiler 100% down
for 1 week.

Another Tech found that the harness to the transformer had been badly
burnt (burner box seal leak ?) .. and all insulation burnt off harness €“
replaced transformer & harness. Could be as a result of all the work
rather than root cause.

After lot of investigation €“ Tech found electrode wires had been
interchanged (presumably during one of many electrode changes) €“ causing
wrong direction of spark €“ and maybe damage to cct boards. Baxi really
should have non-interchangeable plugs on these leads to prevent such a
mix up.


Today again another Tech visit €“ another pair of cct boards and ignition
board harness, still the same €¦. Intermittently boiler fails to ignite
on first strike and as you hear each €˜click of attempt you can see a
flash over on rear of ignition PCB €¦ in area to rear of where
electrode connects.

My assumption is electrode failing to arc €¦ the energy is built up and
has to dissipate somewhere €“ and flashes over on back of board.

This flash over may be the cause of damaging the boards €“ or the effect
of an already damaged boards.

List of parts so far €¦

Initial fault €“ Explosive ignition
New burner box door seal
New style ceramic burner
New electrodes (twice)
New flame sensor
New electrode harness
New ignition board

Increased to €“ also intermittent lock out
New burner box door to allow new style electrodes (folded edge type)
New electrodes (new longer style)
New flame sensor
New condensate trap (new style)
Replaced heat exchanger
Replaced flow thermistor
Replaced Ignition board cct board (twice)
Replaced Control cct board


Increased to 100% lock-out every start (flash over)
Replaced flow thermostat
Replaced Ignition board cct board (twice)
Replaced Control cct board
Replaced ignition transformer
Replaced ignition harness
Replaced main harness

Back to €“ explosive ignition (flash over)
Replaced Ignition board cct board
Replaced Control cct board
Replaced ignition harness

Fault free for 6 weeks

Back to explosive ignition (flash over)
Replaced Ignition board cct board
Replaced Control cct board
Replaced ignition harness


So significant cost of 10 circuit boards, complete heat exchanger,
burner, burner door upgrade €¦ still ongoing.

Has had 23 Tech visits, 9 different individuals, and more than 60 Hrs on
site.



Anybody experienced such a fault €“ thought I would ask as this is
dragging on for so long, about the only items not changed are gas valve
and fan.

rick wrote:



Anybody experienced such a fault €“ thought I would ask as this is
dragging on for so long, about the only items not changed are gas valve
and fan.


Many moons ago we had and Ideal condensing boiler that started lighting
explosively. Turned out to be a faulty gas valve that was letting gas into
the combustion chamber before the "pilot igniter" had lit. This boiler had
a two stage gas valve, the first stage admitting gas to an electronically
lit pilot and then the second stage is supposed to only open once a flame
has been detected in the pilot light.

Does your boiler have a similar system? I suspect that they've all moved
over to "single stage" ignition of the main burner but you never know...

Tim

--
Please don't feed the trolls

On 04/11/2016 19:17, Tim+ wrote:
rick wrote:

Does your boiler have a similar system? I suspect that they've all moved
over to "single stage" ignition of the main burner but you never know...

Tim



Single stage I think ... no pilot flame ... just straight electrode for
ignition along with a flame failure detector.


I asked same Q ... on DIYnot forum ........ and have 2 guys who state
this is an obvious fault, simply fixed - known top all (except the 9
Gas Safe Techs who have been to my place presumably) but they are not
prepared to tell me what it is - even though I will not be touching gas
myslef.

rick wrote:
On 04/11/2016 19:17, Tim+ wrote:
rick wrote:

Does your boiler have a similar system? I suspect that they've all moved
over to "single stage" ignition of the main burner but you never know...

Tim



Single stage I think ... no pilot flame ... just straight electrode for
ignition along with a flame failure detector.


I asked same Q ... on DIYnot forum ........ and have 2 guys who state
this is an obvious fault, simply fixed - known top all (except the 9
Gas Safe Techs who have been to my place presumably) but they are not
prepared to tell me what it is - even though I will not be touching gas
myslef.


Ah, *******. Dontcha just luv 'em? ;-)

Getting back to your boiler one would imagine that it would have a "purge"
phase following a failed ignition to prevent enough gas building up to
cause an explosive ignition. Still makes me wonder if your gas valve is
bypassing gas slightly resulting in gas build up in the combustion chamber
before the next ignition sequence.

It does sound though as if there must be another fault too to explain the
ignition failures.

Tim

--
Please don't feed the trolls

Tim+ wrote:
rick wrote:
On 04/11/2016 19:17, Tim+ wrote:
rick wrote:

Does your boiler have a similar system? I suspect that they've all moved
over to "single stage" ignition of the main burner but you never know...

Tim



Single stage I think ... no pilot flame ... just straight electrode for
ignition along with a flame failure detector.


I asked same Q ... on DIYnot forum ........ and have 2 guys who state
this is an obvious fault, simply fixed - known top all (except the 9
Gas Safe Techs who have been to my place presumably) but they are not
prepared to tell me what it is - even though I will not be touching gas
myslef.


Ah, *******. Dontcha just luv 'em? ;-)

Getting back to your boiler one would imagine that it would have a "purge"
phase following a failed ignition to prevent enough gas building up to
cause an explosive ignition. Still makes me wonder if your gas valve is
bypassing gas slightly resulting in gas build up in the combustion chamber
before the next ignition sequence.

It does sound though as if there must be another fault too to explain the
ignition failures.

Tim


On further reflection, it may be the the gas valve as well as leaking
slightly isn't passing enough gas when it's supposed to be open to get the
gas mixture right for ignition. All in all I would have thought a
replacement valve was the obvious next step.

(I should add I'm not a gas fitter, just interested in how things work, or
ought to work).

Tim

--
Please don't feed the trolls

On Friday, 4 November 2016 23:36:43 UTC, Tim+ wrote:
Tim+ wrote:
rick wrote:
On 04/11/2016 19:17, Tim+ wrote:
rick wrote:

Does your boiler have a similar system? I suspect that they've all moved
over to "single stage" ignition of the main burner but you never know...

Tim



Single stage I think ... no pilot flame ... just straight electrode for
ignition along with a flame failure detector.


I asked same Q ... on DIYnot forum ........ and have 2 guys who state
this is an obvious fault, simply fixed - known top all (except the 9
Gas Safe Techs who have been to my place presumably) but they are not
prepared to tell me what it is - even though I will not be touching gas
myslef.


Ah, *******. Dontcha just luv 'em? ;-)

Getting back to your boiler one would imagine that it would have a "purge"
phase following a failed ignition to prevent enough gas building up to
cause an explosive ignition. Still makes me wonder if your gas valve is
bypassing gas slightly resulting in gas build up in the combustion chamber
before the next ignition sequence.

It does sound though as if there must be another fault too to explain the
ignition failures.

Tim


On further reflection, it may be the the gas valve as well as leaking
slightly isn't passing enough gas when it's supposed to be open to get the
gas mixture right for ignition. All in all I would have thought a
replacement valve was the obvious next step.

(I should add I'm not a gas fitter, just interested in how things work, or
ought to work).

Yes faulty gas valve could cause problems.
Normally, gas accumulations in the boiler are flushed away in the pre-purge part of the cycle. So it would have to be a big leak.

Gas explosions can be caused if there is too much air/insufficient gas in the mixture.
So partially blocked gas jet can cause this problem.
Usually just wire brushed and poked clear with a bit of wire.
May not be apparent during normal operation if boiler is oversized (quite common)

In article , Tim+ wrote:
Tim+ wrote:
rick wrote:
On 04/11/2016 19:17, Tim+ wrote:
rick wrote:

Does your boiler have a similar system? I suspect that they've all
moved over to "single stage" ignition of the main burner but you
never know...

Tim



Single stage I think ... no pilot flame ... just straight electrode
for ignition along with a flame failure detector.


I asked same Q ... on DIYnot forum ........ and have 2 guys who state
this is an obvious fault, simply fixed - known top all (except the 9
Gas Safe Techs who have been to my place presumably) but they are not
prepared to tell me what it is - even though I will not be touching
gas myslef.


Ah, *******. Dontcha just luv 'em? ;-)

Getting back to your boiler one would imagine that it would have a
"purge" phase following a failed ignition to prevent enough gas
building up to cause an explosive ignition. Still makes me wonder if
your gas valve is bypassing gas slightly resulting in gas build up in
the combustion chamber before the next ignition sequence.

It does sound though as if there must be another fault too to explain
the ignition failures.

Tim


On further reflection, it may be the the gas valve as well as leaking
slightly isn't passing enough gas when it's supposed to be open to get
the gas mixture right for ignition. All in all I would have thought a
replacement valve was the obvious next step.

(I should add I'm not a gas fitter, just interested in how things work,
or ought to work).

Tim

I had a similar sounding problem on my, then, 25 year old, boiler. It was
due to the overhest thermostat failing.

--
from KT24 in Surrey, England

charles wrote:
In article ,

I had a similar sounding problem on my, then, 25 year old, boiler. It was
due to the overhest thermostat failing.


I could see that causing inappropriate lock-out but explosive ignition.

Tim


--
Please don't feed the trolls

On 04/11/2016 23:36, Tim+ wrote:
Tim+ wrote:


On further reflection, it may be the the gas valve as well as leaking
slightly isn't passing enough gas when it's supposed to be open to get the
gas mixture right for ignition. All in all I would have thought a
replacement valve was the obvious next step.

(I should add I'm not a gas fitter, just interested in how things work, or
ought to work).

Tim



That was my thought ... not enough gas so it fails initial 'strike'
then there is too much gas in there for when it does light - hence the
bang .... but no proof of that.

rick wrote:

Baxi Barcelona, under service contract - in May this year started giving
intermittent €˜explosive ignition €¦ when it happens gives a seriously
loud bang
This boiler had been upgraded to 100HE spec some years gao.

Multiple visits and loads of parts €¦ fault just got worse €“ was also now
failing to ignite and going into Lock out .. every couple of days.

What is the number of red led lockout flashes you are getting
is the gas valve modulating correctly when it is working

-

On 06/11/2016 00:14, Mark wrote:

What is the number of red led lockout flashes you are getting
is the gas valve modulating correctly when it is working

-



Most of time - it does not lock out, just explosive ignition .........
when the lock out issue was happening (2 months ago)
It was safety lock out ... Red LED flashing aprox once per second.

rick wrote:
On 06/11/2016 00:14, Mark wrote:

What is the number of red led lockout flashes you are getting
is the gas valve modulating correctly when it is working

-



Most of time - it does not lock out, just explosive ignition .........
when the lock out issue was happening (2 months ago)
It was safety lock out ... Red LED flashing aprox once per second.




I'm sticking with gas valve issues. ;-)

Tim

--
Please don't feed the trolls

"Tim+" wrote in message
...
rick wrote:
On 06/11/2016 00:14, Mark wrote:

What is the number of red led lockout flashes you are getting
is the gas valve modulating correctly when it is working

-



Most of time - it does not lock out, just explosive ignition .........
when the lock out issue was happening (2 months ago)
It was safety lock out ... Red LED flashing aprox once per second.




I'm sticking with gas valve issues. ;-)

Yeah, me too, particularly given all the controller changes
and the explosive ignition continuing thru all those and
the fact that its about all that hasnt been changed yet.
Presumably with an ignition fault as well which is why
you get the explosive ignitions as well.

Fits with the prats that say its a well known problem
but arent prepared to say what it is so you dont change
it yourself.

On 06/11/2016 13:15, Tim+ wrote:
rick wrote:
On 06/11/2016 00:14, Mark wrote:

What is the number of red led lockout flashes you are getting
is the gas valve modulating correctly when it is working

-



Most of time - it does not lock out, just explosive ignition .........
when the lock out issue was happening (2 months ago)
It was safety lock out ... Red LED flashing aprox once per second.




I'm sticking with gas valve issues. ;-)

Tim



I'll let you know how it goes :-)

rick wrote:

On 06/11/2016 00:14, Mark wrote:

What is the number of red led lockout flashes you are getting
is the gas valve modulating correctly when it is working


Most of time - it does not lock out, just explosive ignition .........
when the lock out issue was happening (2 months ago)
It was safety lock out ... Red LED flashing aprox once per second.

if you have had the updated pcb board fitted was the yellow jumper removed
you get a number of led flashes then a 1sec pause which then repeats to give
an indication to what is causing the lockout
also in my experience that boiler need to run with the temp knob setting no
more then 1/3 on

-

On 07/11/2016 00:20, Mark wrote:

if you have had the updated pcb board fitted was the yellow jumper removed
you get a number of led flashes then a 1sec pause which then repeats to give
an indication to what is causing the lockout
also in my experience that boiler need to run with the temp knob setting no
more then 1/3 on

-




Took a look at the card ( ans 2 spares) jumpers 1, 3 & 4 are fitted
(4=yellow)


Not sure why you would want to lower temp ?......... I have an
underfloor heating system, the manufacturers advice was to run boiler at
maximum temp.
So when store call for heat - boiler will work at maximum efficiency ...
they advise running at lower temp will reduce efficiency.

rick wrote:
On 07/11/2016 00:20, Mark wrote:

if you have had the updated pcb board fitted was the yellow jumper removed
you get a number of led flashes then a 1sec pause which then repeats to give
an indication to what is causing the lockout
also in my experience that boiler need to run with the temp knob setting no
more then 1/3 on

-




Took a look at the card ( ans 2 spares) jumpers 1, 3 & 4 are fitted
(4=yellow)


Not sure why you would want to lower temp ?......... I have an
underfloor heating system, the manufacturers advice was to run boiler at
maximum temp.
So when store call for heat - boiler will work at maximum efficiency ...
they advise running at lower temp will reduce efficiency.


I think they're talking ********. If you have underfloor heating you have a
huge radiating surface and consequently you should be able to heat your
house with a lower system temperature. (Imagine having just having one
radiator to heat the whole house. It would have to be f*cking hot! The more
radiators you have the lower the system temperature can be.)

In theory boilers work more efficiently at lower temperatures due to
greater heat recovery from condensation. The lower the temperature of the
return flow the greater the heat recovery from the flue gasses.

So it seems you have incompetent repair men and an incompetent
manufacturer. Maybe this explains some of your problems? ;-)

Tim

--
Please don't feed the trolls

On 07/11/2016 19:18, Tim+ wrote:
rick wrote:
On 07/11/2016 00:20, Mark wrote:

if you have had the updated pcb board fitted was the yellow jumper removed
you get a number of led flashes then a 1sec pause which then repeats to give
an indication to what is causing the lockout
also in my experience that boiler need to run with the temp knob setting no
more then 1/3 on

-




Took a look at the card ( ans 2 spares) jumpers 1, 3 & 4 are fitted
(4=yellow)


Not sure why you would want to lower temp ?......... I have an
underfloor heating system, the manufacturers advice was to run boiler at
maximum temp.
So when store call for heat - boiler will work at maximum efficiency ...
they advise running at lower temp will reduce efficiency.


I think they're talking ********. If you have underfloor heating you have a
huge radiating surface and consequently you should be able to heat your
house with a lower system temperature. (Imagine having just having one
radiator to heat the whole house. It would have to be f*cking hot! The more
radiators you have the lower the system temperature can be.)

In theory boilers work more efficiently at lower temperatures due to
greater heat recovery from condensation. The lower the temperature of the
return flow the greater the heat recovery from the flue gasses.

So it seems you have incompetent repair men and an incompetent
manufacturer. Maybe this explains some of your problems? ;-)

Tim


Why then would you have a 'hot setting' if it makes no sense .... just
wondering.
It has been on max setting for 12 years. (maybe wrongly)


On the comment "you should be able to heat your house with a lower
system temperature."
yes .. but the more heat I store in Thermal store ... i.e. the battery,
the more the low temp loop for UFH can run for before boiler needs to
call for boiler input again.

Fewer high efficient burns are better than multiple burns.

rick wrote:
On 07/11/2016 19:18, Tim+ wrote:
rick wrote:
On 07/11/2016 00:20, Mark wrote:

if you have had the updated pcb board fitted was the yellow jumper removed
you get a number of led flashes then a 1sec pause which then repeats to give
an indication to what is causing the lockout
also in my experience that boiler need to run with the temp knob setting no
more then 1/3 on

-




Took a look at the card ( ans 2 spares) jumpers 1, 3 & 4 are fitted
(4=yellow)


Not sure why you would want to lower temp ?......... I have an
underfloor heating system, the manufacturers advice was to run boiler at
maximum temp.
So when store call for heat - boiler will work at maximum efficiency ...
they advise running at lower temp will reduce efficiency.


I think they're talking ********. If you have underfloor heating you have a
huge radiating surface and consequently you should be able to heat your
house with a lower system temperature. (Imagine having just having one
radiator to heat the whole house. It would have to be f*cking hot! The more
radiators you have the lower the system temperature can be.)

In theory boilers work more efficiently at lower temperatures due to
greater heat recovery from condensation. The lower the temperature of the
return flow the greater the heat recovery from the flue gasses.

So it seems you have incompetent repair men and an incompetent
manufacturer. Maybe this explains some of your problems? ;-)

Tim


Why then would you have a 'hot setting' if it makes no sense .... just
wondering.

If you have a conventional "under-radiatored" house, you may need a higher
boiler temp to achieve satisfactory heating. With new condensing boilers
systems though it's normal to fit bigger radiators and run the system at a
lower temperature for increased efficiency. The same boiler may be used in
either situation. Hence the temperature control.


It has been on max setting for 12 years. (maybe wrongly)


On the comment "you should be able to heat your house with a lower
system temperature."
yes .. but the more heat I store in Thermal store ... i.e. the battery,
the more the low temp loop for UFH can run for before boiler needs to
call for boiler input again.

Fewer high efficient burns are better than multiple burns.


Ah, didn't know that you had a thermal store but I'm not sure that affects
the argument. How much difference it makes in practice I don't know.

Tim

--
Please don't feed the trolls