Hi all,

I got a call tonight from an elderly neighbour we keep an eye on,
saying her boiler hadn't come on (and her laptop won't come on
either). This is the same one who needed a new CH pump, basic
Potterton timer and thermal rad valves sorting that you advised me on
previously (and are all now / still working fine). ;-)

I popped over and long-short it looks like there has been some burning
on the controller PCB (she said she had heard a small 'bang' earlier
but wasn't sure where it had come from).

https://dl.dropboxusercontent.com/u/...rd%20front.jpg
https://dl.dropboxusercontent.com/u/...ard%20back.jpg

The fuse had also blown.

So, two questions really. Is there anything running from that board
that could start drawing more current than normal that could overload
the PCB / relay / tracks like that (and if so what), or is it just one
of those things that can happen on those boards please?

If it is just that the board has failed because of bad design (or dry
joint / whatever) could someone with a reasonable eye, a soldering
iron and some bright, tinned copper wire, repair the PCB and still
find the rest of the board functional?

If I can find a replacement controller and she can afford / justify it
(over getting a new boiler etc .. 'Warmfront', free / heavily
subsidised / ripoff? ... as she is 70+ and registered disabled etc),
what are the chances of that one going bang as well?

All I can see hanging off that board is the fan (been replaced twice
now I think), the gas control valve, boiler stat and the air pressure
switch so I'm not sure if any of those could go low resistance or
short (happy to test resistance if anyone can give me a rough idea
what they should be please).

All the best and thanks for your time etc.

Cheers, T i m

On 27/02/2014 22:07, T i m wrote:
Hi all,

I got a call tonight from an elderly neighbour we keep an eye on,
saying her boiler hadn't come on (and her laptop won't come on
either). This is the same one who needed a new CH pump, basic
Potterton timer and thermal rad valves sorting that you advised me on
previously (and are all now / still working fine). ;-)

I popped over and long-short it looks like there has been some burning
on the controller PCB (she said she had heard a small 'bang' earlier
but wasn't sure where it had come from).

https://dl.dropboxusercontent.com/u/...rd%20front.jpg
https://dl.dropboxusercontent.com/u/...ard%20back.jpg

The fuse had also blown.

So, two questions really. Is there anything running from that board
that could start drawing more current than normal that could overload
the PCB / relay / tracks like that (and if so what), or is it just one
of those things that can happen on those boards please?

If it is just that the board has failed because of bad design (or dry
joint / whatever) could someone with a reasonable eye, a soldering
iron and some bright, tinned copper wire, repair the PCB and still
find the rest of the board functional?

If I can find a replacement controller and she can afford / justify it
(over getting a new boiler etc .. 'Warmfront', free / heavily
subsidised / ripoff? ... as she is 70+ and registered disabled etc),
what are the chances of that one going bang as well?

All I can see hanging off that board is the fan (been replaced twice
now I think), the gas control valve, boiler stat and the air pressure
switch so I'm not sure if any of those could go low resistance or
short (happy to test resistance if anyone can give me a rough idea
what they should be please).

All the best and thanks for your time etc.

Cheers, T i m

It looks as if some corrosive liquid has gone across back of the PCB
which has been conductive.

I assume mains voltages are on this PCB so creating heat and charring.

Unfortunately charred PCB is also rather conductive so I would regard
the PCB is pretty terminal, or certainly the affected area.

You might find one on eBay if you're lucky, but best to make sure that
whatever caused the charring in the first place doesn't happen again.

At a push you might be able to lift various components up and wire
directly, and cut tracks that enter the charred area.

The ECO boiler replacement scheme is still running depending on her
income. At least she will get some form of guarantee with it. Also a
maintenance contract might cost less than savings in her gas bill.
Having a non working boiler puts her at the top of the list.

On Thu, 27 Feb 2014 22:23:56 +0000, Fredxxx wrote:

It looks as if some corrosive liquid has gone across back of the PCB
which has been conductive.

Firstly, thanks for your fast reply. ;-)

Whilst it's possible something has got on there, I didn't see any sign
of anything in the surrounding area (above on the metalwork etc).

I assume mains voltages are on this PCB so creating heat and charring.


I believe so yes.

Unfortunately charred PCB is also rather conductive so I would regard
the PCB is pretty terminal, or certainly the affected area.

Ah, good point.

You might find one on eBay if you're lucky, but best to make sure that
whatever caused the charring in the first place doesn't happen again.

There are both new and s/h so that isn't such a problem (I've since
checked). It was more if the charring was caused by a current overdraw
then we would need to address that first. If it was an h/r joint then
a new / working one should just carry on fine?

At a push you might be able to lift various components up and wire
directly, and cut tracks that enter the charred area.

Understood.

The ECO boiler replacement scheme is still running depending on her
income.

So that would include any pension / benefits etc?

At least she will get some form of guarantee with it.

True.

Also a
maintenance contract might cost less than savings in her gas bill.

Is that always the case? She has cavity wall insulation, double
glazing and loft insulation. Even when the boiler was out for a few
days the last time (timer fell to bits) the house seemed to stay
pretty warm, even when quite cold outside. Coming back into this
Victorian EOT reminded us how cold things can get! I'm thinking that
if her existing boiler doesn't have to work very hard, even if less
efficient than the offerings of today, how long would it take her to
recoup the cost of a new boiler if she had to pay for one herself? If
it's free then it's win-win of course, as long as it's as cheap to
maintain long term).

Having a non working boiler puts her at the top of the list.

That was my though but wondered how quick they might be able to
respond, even if she was at the top etc?

Thanks again for your time.

Cheers, T i m

On 27/02/2014 22:55, T i m wrote:
On Thu, 27 Feb 2014 22:23:56 +0000, Fredxxx wrote:

It looks as if some corrosive liquid has gone across back of the PCB
which has been conductive.

Firstly, thanks for your fast reply. ;-)

Whilst it's possible something has got on there, I didn't see any sign
of anything in the surrounding area (above on the metalwork etc).

OK - I was going by the suspicious vertical line on the back of the PCB.

I assume mains voltages are on this PCB so creating heat and charring.


I believe so yes.

Unfortunately charred PCB is also rather conductive so I would regard
the PCB is pretty terminal, or certainly the affected area.

Ah, good point.

You might find one on eBay if you're lucky, but best to make sure that
whatever caused the charring in the first place doesn't happen again.

There are both new and s/h so that isn't such a problem (I've since
checked). It was more if the charring was caused by a current overdraw
then we would need to address that first. If it was an h/r joint then
a new / working one should just carry on fine?

At a push you might be able to lift various components up and wire
directly, and cut tracks that enter the charred area.

Understood.

The ECO boiler replacement scheme is still running depending on her
income.

So that would include any pension / benefits etc?

Yes, I believe they have to be under £17k or so.

At least she will get some form of guarantee with it.

True.

Also a
maintenance contract might cost less than savings in her gas bill.

Is that always the case? She has cavity wall insulation, double
glazing and loft insulation. Even when the boiler was out for a few
days the last time (timer fell to bits) the house seemed to stay
pretty warm, even when quite cold outside. Coming back into this
Victorian EOT reminded us how cold things can get! I'm thinking that
if her existing boiler doesn't have to work very hard, even if less
efficient than the offerings of today, how long would it take her to
recoup the cost of a new boiler if she had to pay for one herself? If
it's free then it's win-win of course, as long as it's as cheap to
maintain long term).

Well, what's her gas bill? Her current one, I believe, has a SEBUK
rating of 68%, new condensing would be 90+%.

Having a non working boiler puts her at the top of the list.

That was my though but wondered how quick they might be able to
respond, even if she was at the top etc?

I'm afraid you will have to phone and find out. I guess at the time she
phones the boiler won't be working, so what if you then repair it
afterwards?

Thanks again for your time.

Cheers, T i m

Pleasure.

On Thu, 27 Feb 2014 23:40:13 +0000, Fredxxx wrote:

snips

The ECO boiler replacement scheme is still running depending on her
income.

So that would include any pension / benefits etc?

Yes, I believe they have to be under £17k or so.

Ok, that's handy to know, thanks.

At least she will get some form of guarantee with it.

True.

Also a
maintenance contract might cost less than savings in her gas bill.

Is that always the case? She has cavity wall insulation, double
glazing and loft insulation. Even when the boiler was out for a few
days the last time (timer fell to bits) the house seemed to stay
pretty warm, even when quite cold outside. Coming back into this
Victorian EOT reminded us how cold things can get! I'm thinking that
if her existing boiler doesn't have to work very hard, even if less
efficient than the offerings of today, how long would it take her to
recoup the cost of a new boiler if she had to pay for one herself? If
it's free then it's win-win of course, as long as it's as cheap to
maintain long term).

Well, what's her gas bill?

Good question, I'll see if I can find out.

Her current one, I believe, has a SEBUK
rating of 68%, new condensing would be 90+%.

So, ~20+% improvement on her gas bill. Nice if she gets the
replacement system free and it doesn't cost her more that 20% of her
current bill to maintain. ;-)

Having a non working boiler puts her at the top of the list.

That was my though but wondered how quick they might be able to
respond, even if she was at the top etc?

I'm afraid you will have to phone and find out.

Understood.

I guess at the time she
phones the boiler won't be working, so what if you then repair it
afterwards?

Well, I think we will have to play that one by ear. If they offer her
a free (or heavily discounted) solution and it's going to be done
reasonably quickly then I'll not bother with her old system and we
will sort out alternative heating for her over the interim (she has an
immersion water heater etc). If it's going to cost her lots and / or
take ages (weeks) then I might affect a temporary repair for her?


Thanks again, cheers, T i m

On Thu, 27 Feb 2014 22:23:56 +0000, Fredxxx wrote:

On 27/02/2014 22:07, T i m wrote:
Hi all,

I got a call tonight from an elderly neighbour we keep an eye on,
saying her boiler hadn't come on (and her laptop won't come on
either). This is the same one who needed a new CH pump, basic
Potterton timer and thermal rad valves sorting that you advised me on
previously (and are all now / still working fine). ;-)

I popped over and long-short it looks like there has been some burning
on the controller PCB (she said she had heard a small 'bang' earlier
but wasn't sure where it had come from).

https://dl.dropboxusercontent.com/u/...rd%20front.jpg
https://dl.dropboxusercontent.com/u/...ard%20back.jpg

The fuse had also blown.

So, two questions really. Is there anything running from that board
that could start drawing more current than normal that could overload
the PCB / relay / tracks like that (and if so what), or is it just one
of those things that can happen on those boards please?

If it is just that the board has failed because of bad design (or dry
joint / whatever) could someone with a reasonable eye, a soldering
iron and some bright, tinned copper wire, repair the PCB and still
find the rest of the board functional?

If I can find a replacement controller and she can afford / justify it
(over getting a new boiler etc .. 'Warmfront', free / heavily
subsidised / ripoff? ... as she is 70+ and registered disabled etc),
what are the chances of that one going bang as well?

All I can see hanging off that board is the fan (been replaced twice
now I think), the gas control valve, boiler stat and the air pressure
switch so I'm not sure if any of those could go low resistance or
short (happy to test resistance if anyone can give me a rough idea
what they should be please).

All the best and thanks for your time etc.

Cheers, T i m

It looks as if some corrosive liquid has gone across back of the PCB
which has been conductive.

That seems the most likely cause since the topside view doesn't show
any burnt out components (they look like they've been victim to
whatever else it was that caused the PCB to char).

So, in answer to the OP's implied question " is [it] just that the
board has failed because of bad design" the answer is no. Also, to
answer his first two questions, there's no evidence of blown
_anything_ (other than the safety fuse) so it seems not to have
suffered as a result of a peripheral fault and the "just one of those
things that can happen on those boards" is answered by "Yes, if you
count contamination by a conductive liquid as being "just one of those
things"".


I assume mains voltages are on this PCB so creating heat and charring.

There are LNE markings top right corner of the topside picture so
that seems to be a safe bet. Also, the fuse is in line with the
connection marked L.


Unfortunately charred PCB is also rather conductive so I would regard
the PCB is pretty terminal, or certainly the affected area.

You might find one on eBay if you're lucky, but best to make sure that
whatever caused the charring in the first place doesn't happen again.

At a push you might be able to lift various components up and wire
directly, and cut tracks that enter the charred area.

Whether the board is repaired or replaced, it looks like the OP will
have to check for the source of the liquid ingress and repair the leak
or rig up a plastic deflector to protect against condensation drips
before putting the boiler back into service.


The ECO boiler replacement scheme is still running depending on her
income. At least she will get some form of guarantee with it. Also a
maintenance contract might cost less than savings in her gas bill.
Having a non working boiler puts her at the top of the list.
--
Regards, J B Good

On Thu, 27 Feb 2014 22:07:34 +0000, T i m wrote:

Hi all,

I got a call tonight from an elderly neighbour we keep an eye on,
saying her boiler hadn't come on (and her laptop won't come on
either). This is the same one who needed a new CH pump, basic
Potterton timer and thermal rad valves sorting that you advised me on
previously (and are all now / still working fine). ;-)

I popped over and long-short it looks like there has been some burning
on the controller PCB (she said she had heard a small 'bang' earlier
but wasn't sure where it had come from).

https://dl.dropboxusercontent.com/u/...rd%20front.jpg
https://dl.dropboxusercontent.com/u/...ard%20back.jpg

The fuse had also blown.

So, two questions really. Is there anything running from that board
that could start drawing more current than normal that could overload
the PCB / relay / tracks like that (and if so what), or is it just one
of those things that can happen on those boards please?

If it is just that the board has failed because of bad design (or dry
joint / whatever) could someone with a reasonable eye, a soldering
iron and some bright, tinned copper wire, repair the PCB and still
find the rest of the board functional?

If I can find a replacement controller and she can afford / justify it
(over getting a new boiler etc .. 'Warmfront', free / heavily
subsidised / ripoff? ... as she is 70+ and registered disabled etc),
what are the chances of that one going bang as well?

All I can see hanging off that board is the fan (been replaced twice
now I think), the gas control valve, boiler stat and the air pressure
switch so I'm not sure if any of those could go low resistance or
short (happy to test resistance if anyone can give me a rough idea
what they should be please).

All the best and thanks for your time etc.

Cheers, T i m


Excellent photography by the way.

What started it was a simple dry soldered joint on the second
(counting from the bottom) of that 4 way terminal block. Looks like
the fibreglass has actually caught fire, nasty. I very much doubt if
anything external to the board "caused" it.

On Thu, 27 Feb 2014 22:40:26 +0000, Graham. wrote:


https://dl.dropboxusercontent.com/u/...rd%20front.jpg
https://dl.dropboxusercontent.com/u/...ard%20back.jpg


Excellent photography by the way.

Cheers! It's just the std camera on my Samsung Galaxy SII and is a bit
of a compromise compared with even my little Fuji Z35 when it comes to
close up work. That said, the SII is always on my hip so ....

What started it was a simple dry soldered joint on the second
(counting from the bottom) of that 4 way terminal block.

I've just given it a quick clean up (some meths and a toothbrush) and
you mat be able to see the seat of the problem a little clearer now:

https://dl.dropboxusercontent.com/u/...ck%20clean.jpg

I've highlighted the position of the relay so it looks now like it
might have been an issue between one of the relay output pins and the
track across to the connector you mentioned. It's not clear if it was
a single point as it seems to be spread between the relay pin and the
connector, so the track?

Looks like
the fibreglass has actually caught fire, nasty.

Yeah, the black smudge above the main damage washed off pretty quickly
with the meths so I think it was just the smoke residue (burning
resin)?

I very much doubt if
anything external to the board "caused" it.

Thinking out loud So, if it was started by a h/r joint (if it was
just (say) the relay pin), would the damage have run sideways so much?
Could the track itself have been underrated from new and has been
heating up that area? I think the 3rd pin up on the lower connector
block goes to the air pressure switch and (following all the tracks
and links back across the board) is the live supply (via the fuse). I
must admit that burnt track looked like it was at least as large as
some of the main feed tracks?

https://dl.dropboxusercontent.com/u/...ic%2010-16.jpg

shrug

Cheers, T i m

p.s. Oh, her 'dead laptop' turned out to be a broken wire in the very
thin cloverleaf power lead into the PSU. After getting some strange /
unpredictable test results (continuity / voltage) I cut the moulded
plug off and fitted a std one a bit further down the lead and all was
well. I'll get her a new / better cable asap. That earned me full
access to the biscuit tin. ;-)

T i m wrote:
Hi all,

I got a call tonight from an elderly neighbour we keep an eye on,
saying her boiler hadn't come on (and her laptop won't come on
either). This is the same one who needed a new CH pump, basic
Potterton timer and thermal rad valves sorting that you advised me on
previously (and are all now / still working fine). ;-)

I popped over and long-short it looks like there has been some burning
on the controller PCB (she said she had heard a small 'bang' earlier
but wasn't sure where it had come from).

https://dl.dropboxusercontent.com/u/...rd%20front.jpg
https://dl.dropboxusercontent.com/u/...ard%20back.jpg

The fuse had also blown.

So, two questions really. Is there anything running from that board
that could start drawing more current than normal that could overload
the PCB / relay / tracks like that (and if so what), or is it just one
of those things that can happen on those boards please?

If it is just that the board has failed because of bad design (or dry
joint / whatever) could someone with a reasonable eye, a soldering
iron and some bright, tinned copper wire, repair the PCB and still
find the rest of the board functional?

If I can find a replacement controller and she can afford / justify it
(over getting a new boiler etc .. 'Warmfront', free / heavily
subsidised / ripoff? ... as she is 70+ and registered disabled etc),
what are the chances of that one going bang as well?

All I can see hanging off that board is the fan (been replaced twice
now I think), the gas control valve, boiler stat and the air pressure
switch so I'm not sure if any of those could go low resistance or
short (happy to test resistance if anyone can give me a rough idea
what they should be please).

All the best and thanks for your time etc.

Cheers, T i m


I've had to reverse engineer this board owing to odd failures, it is
straightforward to repair as it is mostly standard parts (only the
trigger tube and transformer look difficult). Dry joints seem to be a
problem though that does not look like yours has failed that way (it
does look like something has dripped on it). You could flip the top off
RLB and check the contacts for damage as well.

Also, the electrolytics dry out over the years causing intermittent
failures and should be replaced.

I can send you the circuit diagram if you post an EMail contact.

The nominal efficiency of the boiler does not look too bad so replacing
it will not save a great deal (it is nominally 69% though probably
rather less by now). Remember the case seals are critical to safety as
the internal pressure is positive, there are incidents posted on the HSE
site.

HTH

Chris K

On Fri, 28 Feb 2014 14:50:13 +0000, Chris K
wrote:

snip

I've had to reverse engineer this board owing to odd failures, it is
straightforward to repair as it is mostly standard parts (only the
trigger tube and transformer look difficult).

Ok.

Dry joints seem to be a
problem though that does not look like yours has failed that way (it
does look like something has dripped on it).

I looked for that today but couldn't see any way any liquid could have
got to that location (not saying it didn't of course).

https://dl.dropboxusercontent.com/u/...0E%2010-16.jpg

You could flip the top off
RLB and check the contacts for damage as well.

Hmmm, nor that's interesting. I've just gone to 'flip the top' off RLB
using a little (2mm) screwdriver (gently, just to get the case moving
etc), under the end away from the burnt bit and my fingers and I've
just ripped the relay straight out of the board? ;-( Would that
suggest that the relay pin in the burnt area could have also been
'questionable' (should I be able to rip a correctly soldered relay
like that, out with a finger and thumb)?

Also, the electrolytics dry out over the years causing intermittent
failures and should be replaced.

Understood (I've done quite a few PC motherboard PSU caps and even our
Swish electric curtain unit). ;-)

I can send you the circuit diagram if you post an EMail contact.

That would be great thanks. The email as shown here is valid.

The nominal efficiency of the boiler does not look too bad so replacing
it will not save a great deal (it is nominally 69% though probably
rather less by now).

And given her house seems to retain heat well (well insulated mid
terrace etc).

Remember the case seals are critical to safety as
the internal pressure is positive, there are incidents posted on the HSE
site.

Understood. I'm not going in there. ;-)

HTH

It may well indeed.

Cheers, T i m

En el artículo , T i m
escribió:

(should I be able to rip a correctly soldered relay
like that, out with a finger and thumb)?

No, but given the condition of the solder joints in your photos, I'm not
surprised.

What was the state of the fuse? If it was a glass one, was the wire
inside just parted or was it completely blackened inside? If blackened,
there's something more fundamental wrong with the board.

I'd start by checking out the four diodes to the right of RLF, since the
incoming mains passes through the fuse, RLF and those 4 diodes. If
there's a short upwind of there, the PCB track may have vaporised in a
vain attempt to save the fuse (cue old joke about expensive
semiconductors sacrificing themselves to save the fuse...)

There's two relays visible in your photos - RLB and RLF. Maybe RLF is
for the fan, but what is RLB for?

--
(\_/)
(='.'=)
(")_(")

On Sat, 1 Mar 2014 02:51:29 +0000, Mike Tomlinson
wrote:

En el artículo , T i m
escribió:

(should I be able to rip a correctly soldered relay
like that, out with a finger and thumb)?

No, but given the condition of the solder joints in your photos, I'm not
surprised.

Ok. ;-)

What was the state of the fuse? If it was a glass one, was the wire
inside just parted or was it completely blackened inside? If blackened,
there's something more fundamental wrong with the board.

Vaporised I think Mike.

I'd start by checking out the four diodes to the right of RLF, since the
incoming mains passes through the fuse, RLF and those 4 diodes. If
there's a short upwind of there, the PCB track may have vaporised in a
vain attempt to save the fuse (cue old joke about expensive
semiconductors sacrificing themselves to save the fuse...)

I have an update on that. I've now got a good second hand board so
short (excuse the pun) of having any figures for the impedance /
resistance for things like the fan (to know if the board was
overloaded etc) and other than them showing short or very low
resistance (we know the total load can't exceed 1A because of the fuse
so (simply) 250 ohms total (fan + gas valve?)) I'm not sure if after
such checks I shouldn't just stick the spare board on and see what
happens? ;-(

There's two relays visible in your photos - RLB and RLF. Maybe RLF is
for the fan, but what is RLB for?

I think RLF handles the gas valve, RLB for the fan.

Cheers, T i m

On Friday, February 28, 2014 11:20:42 PM UTC, T i m wrote:
On Fri, 28 Feb 2014 14:50:13 +0000, Chris K
wrote:

You could flip the top off
RLB and check the contacts for damage as well.

Hmmm, nor that's interesting. I've just gone to 'flip the top' off RLB
using a little (2mm) screwdriver (gently, just to get the case moving
etc), under the end away from the burnt bit and my fingers and I've
just ripped the relay straight out of the board? ;-( Would that
suggest that the relay pin in the burnt area could have also been
'questionable' (should I be able to rip a correctly soldered relay
like that, out with a finger and thumb)?

The nominal efficiency of the boiler does not look too bad so replacing
it will not save a great deal (it is nominally 69% though probably
rather less by now).
And given her house seems to retain heat well (well insulated mid
terrace etc).

Probably retaining the neighbours' heat!

Fires trash soldered joints, so one cant conclude anything there.

Dont overlook that that much overheating will almost surely have killed anything silicon that connected into the burn zone, so replace some diodes IIRC. It also might destroy other components, test or replace any burn zone ones where you can.


NT

On Sat, 1 Mar 2014 00:38:28 -0800 (PST), wrote:

On Friday, February 28, 2014 11:20:42 PM UTC, T i m wrote:
On Fri, 28 Feb 2014 14:50:13 +0000, Chris K
wrote:

You could flip the top off
RLB and check the contacts for damage as well.

Hmmm, nor that's interesting. I've just gone to 'flip the top' off RLB
using a little (2mm) screwdriver (gently, just to get the case moving
etc), under the end away from the burnt bit and my fingers and I've
just ripped the relay straight out of the board? ;-( Would that
suggest that the relay pin in the burnt area could have also been
'questionable' (should I be able to rip a correctly soldered relay
like that, out with a finger and thumb)?

The nominal efficiency of the boiler does not look too bad so replacing
it will not save a great deal (it is nominally 69% though probably
rather less by now).
And given her house seems to retain heat well (well insulated mid
terrace etc).

Probably retaining the neighbours' heat!

And why not. ;-)

Fires trash soldered joints, so one cant conclude anything there.

I'm sure you are right but it seems strange that even away from the
action (heat rises etc) the 3(!) relay pins just pulled out?

Dont overlook that that much overheating will almost surely have killed anything silicon that connected into the burn zone, so replace some diodes IIRC.

Ok. Only D6 is that close.

It also might destroy other components, test or replace any burn zone ones where you can.

I might (OOI) but as mentioned elsewhere I already have a second hand
replacement controller that looks like it's of a later deign with very
much heavier tracks etc.

https://dl.dropboxusercontent.com/u/...l%20boards.jpg

FWIW, I just dropped the old board on the carpet (it actually tumbled
off the chair rather than fell as such) and when I picked it up the
igniter TXFMR was hanging off!

Hmmmm ...

Cheers, T i m

En el artículo , T i m
escribió:

I might (OOI) but as mentioned elsewhere I already have a second hand
replacement controller that looks like it's of a later deign with very
much heavier tracks etc.

https://dl.dropboxusercontent.com/u/...l%20boards.jpg

That looks much better made. I had a similar issue with the PCB for a
Poxi Batterton boiler - a Suprima - it's featured in this group many
times, and the redesigned PCB from Baxi was of far superior
construction.

The boiler featured on Watchdog and after I sent off a snottogram
referring to the programme, BP refunded the cost of the replacement.

FWIW, I just dropped the old board on the carpet (it actually tumbled
off the chair rather than fell as such) and when I picked it up the
igniter TXFMR was hanging off!

It would be worth metering the fan and the gas valve just to make sure
they're not a dead short before trying the replacement board.

--
(\_/)
(='.'=)
(")_(")

On Sat, 01 Mar 2014 10:04:12 +0000, T i m wrote:

FWIW, I just dropped the old board on the carpet (it actually tumbled
off the chair rather than fell as such) and when I picked it up the
igniter TXFMR was hanging off!

Hmmmm ...

Thats one of the benefits of lead-free solder..
and why it is not used in aviation or military equipment.

On Saturday, March 1, 2014 10:04:12 AM UTC, T i m wrote:
On Sat, 1 Mar 2014 00:38:28 -0800 (PST), wrote:
On Friday, February 28, 2014 11:20:42 PM UTC, T i m wrote:


And given her house seems to retain heat well (well insulated mid
terrace etc).

Probably retaining the neighbours' heat!

And why not. ;-)

Fires trash soldered joints, so one cant conclude anything there.

I'm sure you are right but it seems strange that even away from the
action (heat rises etc) the 3(!) relay pins just pulled out?

solder oxidises easily from excess heat. Lead oxide's good for nowt.


NT

On Thu, 27 Feb 2014 22:07:34 +0000, T i m wrote:
[...]

It's a bit hard to see, but it looks like there's a wire filament
bridging across and may have shorted out the board (to the above left
from the charred area on the reverse shot of the board)?

On Fri, 28 Feb 2014 20:39:51 +0000 (UTC), Cursitor Doom
wrote:

On Thu, 27 Feb 2014 22:07:34 +0000, T i m wrote:
[...]

It's a bit hard to see, but it looks like there's a wire filament
bridging across and may have shorted out the board (to the above left
from the charred area on the reverse shot of the board)?

Ah, yes, I can see what you mean on that 'pre cleaning' photo and I
think it's just a bit of cloth or some such (well spotted though). ;-)

I have since mentioned that whilst checking the relay RLB I've managed
with pretty well my finger and thumb and a little bit of effort to
pull it (and the remaining 4 solder joints) right of the board.
Looking closer at the burnt area it could be thought that the burning
might have radiated around what is likely to be one of the two key
relay pins (240V switching) and that if it's like those joints I've
just pulled though, may well have been 'dry'?

Goes to take a picture with the Galaxy SII and when I get back to my
PC it's already on Dropbox 'Camera Uploads' ... brilliant! ;-)

https://dl.dropboxusercontent.com/u/...rd%20relay.jpg

Ok, I may have reasonably strong hands but should I have been able to
do that? ;-(

Cheers, T i m

T i m wrote:

https://dl.dropboxusercontent.com/u/...rd%20relay.jpg

Ok, I may have reasonably strong hands but should I have been able to
do that? ;-(

Looks to have been worryingly easy, are those rings left on the relay
terminals just solder blobs, or the plated-through vias? Are you
planning to repair the board, replacing the burnt out track with a wire?
I'd be de/re-soldering all the other joints in case ...

On Sat, 01 Mar 2014 04:43:43 +0000, Andy Burns
wrote:

T i m wrote:

https://dl.dropboxusercontent.com/u/...rd%20relay.jpg

Ok, I may have reasonably strong hands but should I have been able to
do that? ;-(

Looks to have been worryingly easy,

Indeed.

are those rings left on the relay
terminals just solder blobs, or the plated-through vias?

I think they are just solder blobs Andy.

Are you
planning to repair the board, replacing the burnt out track with a wire?

That was an initial though bus as I've now picked up a second hand
board I'm not sure I can be bothered / it's a good idea.

I'd be de/re-soldering all the other joints in case ...

Well, yes, as I mentioned elsewhere, after a minor tumble onto the
carpet the igniter TXFMR was hanging off!

Cheers, T i m

T i m wrote:
On Sat, 01 Mar 2014 04:43:43 +0000, Andy Burns
wrote:

T i m wrote:

https://dl.dropboxusercontent.com/u/...rd%20relay.jpg

Ok, I may have reasonably strong hands but should I have been able to
do that? ;-(

Looks to have been worryingly easy,

Indeed.

are those rings left on the relay
terminals just solder blobs, or the plated-through vias?

I think they are just solder blobs Andy.

Are you
planning to repair the board, replacing the burnt out track with a wire?

That was an initial though bus as I've now picked up a second hand
board I'm not sure I can be bothered / it's a good idea.

I'd be de/re-soldering all the other joints in case ...

Well, yes, as I mentioned elsewhere, after a minor tumble onto the
carpet the igniter TXFMR was hanging off!

Cheers, T i m


Looks well fried. Seems like there was a dry joint on the relay though
that is the coil connection so it is hard to see how that got burnt as
the currents are quite low (that is the feed to the gas valve(s)).

BTW I've posted the documents to you at your reply address.

Chris

On Fri, 28 Feb 2014 23:41:33 +0000, T i m wrote:

On Fri, 28 Feb 2014 20:39:51 +0000 (UTC), Cursitor Doom
wrote:

On Thu, 27 Feb 2014 22:07:34 +0000, T i m wrote:
[...]

It's a bit hard to see, but it looks like there's a wire filament
bridging across and may have shorted out the board (to the above left
from the charred area on the reverse shot of the board)?

Ah, yes, I can see what you mean on that 'pre cleaning' photo and I
think it's just a bit of cloth or some such (well spotted though). ;-)

I have since mentioned that whilst checking the relay RLB I've managed
with pretty well my finger and thumb and a little bit of effort to
pull it (and the remaining 4 solder joints) right of the board.
Looking closer at the burnt area it could be thought that the burning
might have radiated around what is likely to be one of the two key
relay pins (240V switching) and that if it's like those joints I've
just pulled though, may well have been 'dry'?

Goes to take a picture with the Galaxy SII and when I get back to my
PC it's already on Dropbox 'Camera Uploads' ... brilliant! ;-)

https://dl.dropboxusercontent.com/u/...rd%20relay.jpg

Ok, I may have reasonably strong hands but should I have been able to
do that? ;-(

Cheers, T i m

I too have worked out the part of the circuit shown in your good
photos, by mirroring the back and scaling and superimposing it on the
front.

The track from terminal T5 used to go to the top pin of RLB (normally
open contact), and the track from T7 used to go to the common of RLB.
Both these tracks are burnt out. D6 in series with R13 are just
passing by.

T5 also goes to the boiler contacts via S1 or S2, the other one of
which is fed from the fuse.

When RLB comes on it connects the Fan to the fuse via S1 & S2.

I think the most likely scenario is that the top RLB pin was arcing
and burnt the board, making it conductive and escalating the fault.

Another possibility is that the 1 amp fuse had been replaced by a much
higher value, plus the fan has gone short circuit, fusing the track.

The relay may well be OK as the contacts are rated at 10A. If it was
me, I would probably cut away the burnt bits of the board, solder the
relay back on all pins except the burnt one, and solder bits of tinned
copper wire to replace the burnt tracks. It would be best to check the
fan before switching on again.
--
Dave W

On Sat, 01 Mar 2014 10:37:03 +0000, Dave W
wrote:

snip

I too have worked out the part of the circuit shown in your good
photos, by mirroring the back and scaling and superimposing it on the
front.

Thanks.

The track from terminal T5 used to go to the top pin of RLB (normally
open contact), and the track from T7 used to go to the common of RLB.
Both these tracks are burnt out. D6 in series with R13 are just
passing by.

Ok.

T5 also goes to the boiler contacts via S1 or S2, the other one of
which is fed from the fuse.

Agreed.

When RLB comes on it connects the Fan to the fuse via S1 & S2.

Ok.

I think the most likely scenario is that the top RLB pin was arcing
and burnt the board, making it conductive and escalating the fault.

From the recent findings with RLB coming out with a pull with my
finger and thumb and then the igniter txfmr falling out when I dropped
the PCB on the carpet, I suspect dry joints (especially on this bigger
stuff) were rife. ;-(

Another possibility is that the 1 amp fuse had been replaced by a much
higher value,

I've checked that and it is (was) a 1A Dave. (Would it normally be a
std, quick or slow-blow? I'm guessing std?). It says F1L250V

plus the fan has gone short circuit, fusing the track.

I'll check for that.

The relay may well be OK as the contacts are rated at 10A. If it was
me, I would probably cut away the burnt bits of the board, solder the
relay back on all pins except the burnt one, and solder bits of tinned
copper wire to replace the burnt tracks.

I've managed to get hold of a s/h (and what looks like later)
controller so after checking things like the resistance of the fan I
might just try this spare board. If there is something broken enough
to take out this spare board then that would probably suggest it might
be waiting to see what Warmfront (or whatever they are called now)
come up with?

It would be best to check the
fan before switching on again.

Will do.

Thanks for all your time ...

Cheers, T i m

On Sat, 01 Mar 2014 10:52:20 +0000, T i m wrote:

On Sat, 01 Mar 2014 10:37:03 +0000, Dave W
wrote:

snip

I too have worked out the part of the circuit shown in your good
photos, by mirroring the back and scaling and superimposing it on the
front.

Thanks.

The track from terminal T5 used to go to the top pin of RLB (normally
open contact), and the track from T7 used to go to the common of RLB.
Both these tracks are burnt out. D6 in series with R13 are just
passing by.

Ok.

T5 also goes to the boiler contacts via S1 or S2, the other one of
which is fed from the fuse.

Agreed.

When RLB comes on it connects the Fan to the fuse via S1 & S2.

Ok.

I think the most likely scenario is that the top RLB pin was arcing
and burnt the board, making it conductive and escalating the fault.

From the recent findings with RLB coming out with a pull with my
finger and thumb and then the igniter txfmr falling out when I dropped
the PCB on the carpet, I suspect dry joints (especially on this bigger
stuff) were rife. ;-(

Another possibility is that the 1 amp fuse had been replaced by a much
higher value,

I've checked that and it is (was) a 1A Dave. (Would it normally be a
std, quick or slow-blow? I'm guessing std?). It says F1L250V

plus the fan has gone short circuit, fusing the track.

I'll check for that.

The relay may well be OK as the contacts are rated at 10A. If it was
me, I would probably cut away the burnt bits of the board, solder the
relay back on all pins except the burnt one, and solder bits of tinned
copper wire to replace the burnt tracks.

I've managed to get hold of a s/h (and what looks like later)
controller so after checking things like the resistance of the fan I
might just try this spare board. If there is something broken enough
to take out this spare board then that would probably suggest it might
be waiting to see what Warmfront (or whatever they are called now)
come up with?

It would be best to check the
fan before switching on again.

Will do.

Thanks for all your time ...

Cheers, T i m

Yes, the "F" on the fuse means quick blow. Slow-blow would be "T". The
terminal pins on the new board are not in the same place so I hope
it's obvious how to connect the wires. I agree with your plan to
measure the resistance of the fan to check that it's reasonable.
--
Dave W

On 28/02/2014 23:41, T i m wrote:


https://dl.dropboxusercontent.com/u/...rd%20relay.jpg

Ok, I may have reasonably strong hands but should I have been able to
do that? ;-(


Not if it was properly soldered in. But it's a bit chicken and egg. The
overheating might have melted what were previously perfectly good solder
joints. Or a dry joint may have caused the overheating.
--
Cheers,
Roger
____________
Please reply to Newsgroup. Whilst email address is valid, it is seldom
checked.

On Sun, 02 Mar 2014 10:38:19 +0000, Roger Mills
wrote:

On 28/02/2014 23:41, T i m wrote:


https://dl.dropboxusercontent.com/u/...rd%20relay.jpg

Ok, I may have reasonably strong hands but should I have been able to
do that? ;-(


Not if it was properly soldered in. But it's a bit chicken and egg. The
overheating might have melted what were previously perfectly good solder
joints. Or a dry joint may have caused the overheating.

Understood, especially for the joints around the burnt bit. It doesn't
however explain the igniter txfmr (nearly) falling off that is at the
other end of the board. ;-)

Cheers, T i m

En el artículo , Roger Mills
escribió:

Not if it was properly soldered in. But it's a bit chicken and egg. The
overheating might have melted what were previously perfectly good solder
joints. Or a dry joint may have caused the overheating.

Some cheap relays and wound components (inductors, transformers) come
out of the factory with pins that aren't tinned. Those will appear to
solder ok but actually have made a poor joint where solder surrounds the
pin but doesn't properly bond to it. I'll give you one guess where the
relay at fault in the OP's board was made.

Sometimes it's necessary to take the component off the board, rub the
pins/legs down, tin then re-fit them, to ensure a decent joint.

I'm pretty sure that was the cause of the original fault causing the
arcing around the relay pin and subsequent charring of the OP's original
board.

--
(\_/)
(='.'=)
(")_(")

On Thu, 27 Feb 2014 22:07:34 +0000, T i m wrote:

Hi all,

I got a call tonight from an elderly neighbour we keep an eye on,
saying her boiler hadn't come on (and her laptop won't come on
either). This is the same one who needed a new CH pump, basic
Potterton timer and thermal rad valves sorting that you advised me on
previously (and are all now / still working fine). ;-)

snip

All the best and thanks for your time etc.


I'd just like to say a 'big thanks' to all those who offered feedback,
advice and info on this issue.

Before re-connecting the controller I measured about 79 ohms across
the fan so not far off Chris K's 68. ;-)

Running the fan directly from the mains showed about 275 mA so well
inside the 1A main fuse limit.

When re-connecting the gas valve I found one of the threads stripped
on the connector so I had to take the one from the original board
sigh. Thank goodness for my little 'iroda Solderpro 50k' gas iron.
;-)

Powered it all up whilst monitoring the current on the main fuse and
saw it ramp up to just over ~300mA.

https://dl.dropboxusercontent.com/u/...%20control.jpg

Fan igniter + gas valve pilot pilot igniter off main burner on
and away we went. ;-)

I ran it with the cover off the controller till the CH + water were up
to temp and the boiler shut off. Powered down and made sure none of
the components were running hot then boxed it all back up and was then
given full access to the biscuit tin. ;-)

So, thanks again to all from one warm old dear and I. weg

Cheers, T i m

(It may well be that she's just outside the eligibility for the
Warmfront deal but we will still check it out).

On Sun, 02 Mar 2014 22:43:41 +0000, Tim Streater
wrote:

In article , T i m
wrote:

So, thanks again to all from one warm old dear and I. weg

That should be " ... one warm old dear and me."

Hey, I was talking about grandma, not grammar. ;-)

Now, before getting me coat:

as you should ;-)

1) WTF is weg ??

http://www.internetslang.com/WEG-meaning-definition.asp

2) Kudos to you for persisting with this - looking after an old dear -
that's a good thing you have done there laddie.

Why thanks. She's a good old salt, forever thanking us for the
slightest things and it's really / actually nice to be able to make
her life easier / more comfortable, any way possible.

She is suffering (and has to take morphine regularly) with bad ulcers
on both legs to the point where she may have to have both amputated.

In spite of that, no sooner are you in the door then she's trying to
get up offering tea and food.

Whilst she always seems to have someone (friends and family) ringing
or texting her, she really enjoys real company and my Mrs tries to go
over there as often as possible, especially if she believes she hasn't
had any other visitors that day.

It's no hardship to either of us to help whatever way we can because
it's easy to help nice people. ;-)

Tonight we were talking to her about the idea of getting more use out
of her mobility scooter. It's kept at the bottom of the garden with a
fairy tricky access to the outside world (not such an issue where her
husband was still alive and would bring it round the front for her). I
asked her if there was any reason and / or if she would like the buggy
out the front in one of these secure stores so she could get at it
easier and her reply was 'Oh yes dear, that would be so nice if I
could have some mobility back ...'.

How great would it be to be part of giving that to someone ... ;-)

(Anyone any experience of these secure scooter stores that have a lift
up lid (I think they may be raised electrically), again, might be
something she could get financial help with)?

This sort of things possibly?

http://www.site-safe.co.uk/prod1.htm

Cheers, T i m

On 27/02/2014 22:07, T i m wrote:
If I can find a replacement controller and she can afford / justify it
(over getting a new boiler etc .. 'Warmfront', free / heavily
subsidised / ripoff? ... as she is 70+ and registered disabled etc),
what are the chances of that one going bang as well?

I'm not going to read the entire thread but has anyone mentioned cetltd.com?

Andy

On 03/03/2014 22:46, Vir Campestris wrote:
On 27/02/2014 22:07, T i m wrote:
If I can find a replacement controller and she can afford / justify it
(over getting a new boiler etc .. 'Warmfront', free / heavily
subsidised / ripoff? ... as she is 70+ and registered disabled etc),
what are the chances of that one going bang as well?

I'm not going to read the entire thread but has anyone mentioned
cetltd.com?

Andy

I don't think so, but:
a) The OP obtained a (more or less) working second-hand PCB from
somewhere else
b) I doubt whether Geoff would have accepted the old board because it
probably wasn't repairable

--
Cheers,
Roger
____________
Please reply to Newsgroup. Whilst email address is valid, it is seldom
checked.

On Tue, 04 Mar 2014 11:32:58 +0000, Roger Mills
wrote:

On 03/03/2014 22:46, Vir Campestris wrote:
On 27/02/2014 22:07, T i m wrote:
If I can find a replacement controller and she can afford / justify it
(over getting a new boiler etc .. 'Warmfront', free / heavily
subsidised / ripoff? ... as she is 70+ and registered disabled etc),
what are the chances of that one going bang as well?

I'm not going to read the entire thread but has anyone mentioned
cetltd.com?

Andy

I don't think so, but:
a) The OP obtained a (more or less) working second-hand PCB from
somewhere else

'More or less working' ... I like it. ;-)

b) I doubt whether Geoff would have accepted the old board because it
probably wasn't repairable

I wondered if Geoff would chime in (I've seen him doing his wizardry
in person g) so I'm guessing, if he saw the thread that it probably
wasn't worth his time under the circumstances.

And with a 'more or less working' replacement for 1/4 of the cost of
the cheapest new one is was worth trying, even if it too went up in
smoke (especially so in fact).

Had a replacement not been available I may have repaired the old board
(I've repaired worse) if only as a test and could have completely
re-populated anything that may have failed for very little.

Anyway, it still seems to be working ok. ;-)

Cheers, T i m

On 05/03/2014 22:23, T i m wrote:
On Tue, 04 Mar 2014 11:32:58 +0000, Roger
wrote:


a) The OP obtained a (more or less) working second-hand PCB from
somewhere else

'More or less working' ... I like it. ;-)


I was referring to the fact that you had to replace one of the
connectors which had a stripped thread.
--
Cheers,
Roger
____________
Please reply to Newsgroup. Whilst email address is valid, it is seldom
checked.

On Thu, 06 Mar 2014 20:32:49 +0000, Roger Mills
wrote:

On 05/03/2014 22:23, T i m wrote:
On Tue, 04 Mar 2014 11:32:58 +0000, Roger
wrote:


a) The OP obtained a (more or less) working second-hand PCB from
somewhere else

'More or less working' ... I like it. ;-)


I was referring to the fact that you had to replace one of the
connectors which had a stripped thread.

And a fuse missing, yes, I know, and I liked the description. ;-)

Cheers, T i m