I have a Brittony 80 combi boiler made by Chaffoteaux, which I
installed about ten years ago. Almost every year the heat exchanger
gets partially blocked, resulting in fluctuating temperature of the
domestic hot tap water. I live in a very hard water area.

So a year ago, when I last renewed the heat exchanger, I also
installed a phosphate doser on the water mains inlet pipe to hopefuly
reduce limescale.

However, now, a year later, the heat exchanger seems to be playing up
just the same as befo hot tap water coming out luke warm, then
slightly warmer, but never really hot.

Is this the heat exchanger blocking up again, or could it be something
else?

I can buy yet another heat exchanger tomorrow, but is ther anything
else I should be doing to prolong its life? Water filter, perhaps?

Does anyone know where the filters (if any) are located in a Britony
combi? I can't find any reference to them in the manual, but see to
recall a plumber talking about them once. How often should they be
cleaned?

Thank you,

Jim D

On Sun, 15 Oct 2006 15:24:59 +0100, JimD wrote:


I have a Brittony 80

PS, the latest problems started just after I desludged the system a
few days ago. Could that possibly have anything to do with it - or is
it probably a coincidence?

Jim D

In article ,
JimD writes:
I can buy yet another heat exchanger tomorrow, but is ther anything
else I should be doing to prolong its life? Water filter, perhaps?

I don't know this model, but why not descale it?

I descalled a friend's one from a Baxi using Furnox DS-3.
Dissolve some DS-3 in a large jug of hot water.
Stand the heat exchanger in a washing up bowl to catch
the descaller, and pour into the hot water side of the
heat exchanger slowly. Be prepared for violent descalling
spitting out the acid and acid spray. When you've poured
it all through, empty the heat exchanger out into the bowl,
transfer back to the jug, and the pour through again, until
the heat exchanger stops fizzing. If the descaller goes blue,
it's used up -- discard and mix up some fresh.

DS-3 is available from a plumber's merchant, and possibly
larger B&Q's. I'm assuming the heat exchanger is stainless
steel -- if it's something else, check compatibility with
the DS-3.

DS-3 is sulphamic acid, i.e. pure kettle descaller without
the sand and other rubbish you find mixed in with retail
kettle descallers to dilute them. It has an indicator added
so you can tell it's used up by change of colour, and a smell
so you don't accidently drink it. A tub of it can be useful
for other things too, but don't use it on plastic parts (or
plastic kettles), as it can make them brittle.

--
Andrew Gabriel

On 2006-10-15 15:24:59 +0100, JimD said:


I have a Brittony 80 combi boiler made by Chaffoteaux, which I
installed about ten years ago. Almost every year the heat exchanger
gets partially blocked, resulting in fluctuating temperature of the
domestic hot tap water. I live in a very hard water area.

So a year ago, when I last renewed the heat exchanger, I also
installed a phosphate doser on the water mains inlet pipe to hopefuly
reduce limescale.

However, now, a year later, the heat exchanger seems to be playing up
just the same as befo hot tap water coming out luke warm, then
slightly warmer, but never really hot.

Is this the heat exchanger blocking up again, or could it be something
else?

I can buy yet another heat exchanger tomorrow, but is ther anything
else I should be doing to prolong its life? Water filter, perhaps?

Does anyone know where the filters (if any) are located in a Britony
combi? I can't find any reference to them in the manual, but see to
recall a plumber talking about them once. How often should they be
cleaned?

Thank you,

Jim D

Following on from Andrew's comments, and you certainly should be able
to descale the existing heat exchanger, if a phosphate doser isn't
managing to handle the scaling then an ion exchange water softener is
the solution. A water filter won't do anything about limescale.

Of course descaling will also tell you whether this is the problem.

On 15 Oct 2006 15:39:53 GMT, (Andrew
Gabriel) wrote:

I don't know this model, but why not descale it?

I descalled a friend's one from a Baxi using Furnox DS-3.
Dissolve some DS-3 in a large jug of hot water.
Stand the heat exchanger in a washing up bowl to catch
the descaller, and pour into the hot water side of the
heat exchanger slowly. Be prepared for violent descalling
spitting out the acid and acid spray. When you've poured
it all through, empty the heat exchanger out into the bowl,
transfer back to the jug, and the pour through again, until
the heat exchanger stops fizzing. If the descaller goes blue,
it's used up -- discard and mix up some fresh.

I did try descaling it once - but only with domestic supermarket
descaler. It fizzed and bubbled but didn't unblock it. I've never
tried "DS-3". Where can I obtain that in suitable quantities?

But I think these heat exchangers can also become blocked by rust and
sludge on the other side (non-tapwater) side of the exchanger, can't
they? That's what a corgi reg'd plumber once told me was wrong with
mine, anyway. He pointed oit the bits of black stuff inside the
exchanger and said "that's iron oxide that's blocking it" IIRC. Of
course, he might have been feeding me a line of s**t just to flog me
an overpriced heat-exchanger....

Thanks,

Jim D

On Sun, 15 Oct 2006 16:54:48 +0100, Jim D wrote:

I've never
tried "DS-3". Where can I obtain that in suitable quantities?

Sorry - I didn't see the lower portion of your response - you answered
the above qn - thank you.

Jim D

On Sun, 15 Oct 2006 16:44:28 +0100, Andy Hall
wrote:


Following on from Andrew's comments, and you certainly should be able
to descale the existing heat exchanger, if a phosphate doser isn't
managing to handle the scaling then an ion exchange water softener is
the solution. A water filter won't do anything about limescale.

Of course descaling will also tell you whether this is the problem.

Thanks for the reply. It just occurred to me: scaling is only likely
to occur on the side of the heat exchanger that passes water from the
mains inlet to the sink taps, isn't it? In if that side was scaled up,
then there would be a reduction in flow from the hot taps, wouldn't
there?

Jim D

On 2006-10-15 16:54:48 +0100, Jim D said:

On 15 Oct 2006 15:39:53 GMT, (Andrew
Gabriel) wrote:

I don't know this model, but why not descale it?

I descalled a friend's one from a Baxi using Furnox DS-3.
Dissolve some DS-3 in a large jug of hot water.
Stand the heat exchanger in a washing up bowl to catch
the descaller, and pour into the hot water side of the
heat exchanger slowly. Be prepared for violent descalling
spitting out the acid and acid spray. When you've poured
it all through, empty the heat exchanger out into the bowl,
transfer back to the jug, and the pour through again, until
the heat exchanger stops fizzing. If the descaller goes blue,
it's used up -- discard and mix up some fresh.

I did try descaling it once - but only with domestic supermarket
descaler. It fizzed and bubbled but didn't unblock it. I've never
tried "DS-3". Where can I obtain that in suitable quantities?

Plumbing and heating merchants have it in small and large tubs.


But I think these heat exchangers can also become blocked by rust and
sludge on the other side (non-tapwater) side of the exchanger, can't
they? That's what a corgi reg'd plumber once told me was wrong with
mine, anyway. He pointed oit the bits of black stuff inside the
exchanger and said "that's iron oxide that's blocking it" IIRC. Of
course, he might have been feeding me a line of s**t just to flog me
an overpriced heat-exchanger....

There's really no reason why a properly maintained heating system
should be suffering from sludge.

If it is a sealed system (no header tank on loft) then the only action
that should be needed with a clean system is to dose it annually with
corrosion inhibitor - cost about £20.




Thanks,

Jim D

On 2006-10-15 17:10:01 +0100, Jim D said:

On Sun, 15 Oct 2006 16:44:28 +0100, Andy Hall
wrote:


Following on from Andrew's comments, and you certainly should be able
to descale the existing heat exchanger, if a phosphate doser isn't
managing to handle the scaling then an ion exchange water softener is
the solution. A water filter won't do anything about limescale.

Of course descaling will also tell you whether this is the problem.

Thanks for the reply. It just occurred to me: scaling is only likely
to occur on the side of the heat exchanger that passes water from the
mains inlet to the sink taps, isn't it? In if that side was scaled up,
then there would be a reduction in flow from the hot taps, wouldn't
there?

Jim D

Possibly some, yes.

If the system is sludged, then a different course of action is needed -
basically clean it out and fill adding corrosion inhibitor to the
system afterwards

On Sun, 15 Oct 2006 17:22:05 +0100, Andy Hall
wrote:

There's really no reason why a properly maintained heating system
should be suffering from sludge.

If it is a sealed system (no header tank on loft) then the only action
that should be needed with a clean system is to dose it annually with
corrosion inhibitor - cost about £20.

I have to confess, that is something I haven't done for about 3 years,
....until the other day, when I ran it with de-sludging solution and
then flushed and filled with water+inhibitor.

Jim D

On Sun, 15 Oct 2006 17:23:55 +0100, Andy Hall
wrote:

Thanks for the reply. It just occurred to me: scaling is only likely
to occur on the side of the heat exchanger that passes water from the
mains inlet to the sink taps, isn't it? In if that side was scaled up,
then there would be a reduction in flow from the hot taps, wouldn't
there?

Jim D

Possibly some, yes.

If the system is sludged, then a different course of action is needed -
basically clean it out and fill adding corrosion inhibitor to the
system afterwards

That's exactly what I did, a few days ago, just before this problem
started..

Jim D

On Sun, 15 Oct 2006 17:23:55 +0100, Andy Hall
wrote:


Thanks for the reply. It just occurred to me: scaling is only likely
to occur on the side of the heat exchanger that passes water from the
mains inlet to the sink taps, isn't it? In if that side was scaled up,
then there would be a reduction in flow from the hot taps, wouldn't
there?

Jim D

Possibly some, yes.

A couple more observations:

1) When I turn a hot tap on, the boiled does fire up and stays burning
as long as a hot DHW tap is turned on. As an experiment, I pulled the
contacts off the boiler's DHW flow switch while it was fired up, and
this caused the burner to stop. As soon as I replaced the contacts, it
fired up again.

2) I put my hand on the secondary heat exchanger while it was fired
up. It was stone cold in all places.

Some might question the diverter valve at this point. However, I
remember the tech help guy from Caffateaux telling me that the
diverter valve never goes wrong on these boilers...

Thanks for any further suggestions...

Jim D

On 2006-10-15 17:47:26 +0100, Jim D said:

On Sun, 15 Oct 2006 17:23:55 +0100, Andy Hall
wrote:

Thanks for the reply. It just occurred to me: scaling is only likely
to occur on the side of the heat exchanger that passes water from the
mains inlet to the sink taps, isn't it? In if that side was scaled up,
then there would be a reduction in flow from the hot taps, wouldn't
there?

Jim D

Possibly some, yes.

If the system is sludged, then a different course of action is needed -
basically clean it out and fill adding corrosion inhibitor to the
system afterwards

That's exactly what I did, a few days ago, just before this problem
started..

Jim D

Is it a sealed system or open vented with tank in the loft?

If it's the latter, then pumping over of heating water or sucking of
air into the system because the relative positions of pump,
feed/expansion and vent pipes can cause the water to become more
oxygenated than it otherwise would be. This effectively "uses up" the
inhibitor. You can diagnose this problem if the radiators need
frequent venting and the gas released is air and not hydrogen, or
pumping over can be seen from the vent pipe with the tank getting very
hot.

EIther way, I wonder if you have managed to flush some sludge into the
boiler....

On Sun, 15 Oct 2006 19:19:42 +0100, Andy Hall
wrote:

On 2006-10-15 17:47:26 +0100, Jim D said:

On Sun, 15 Oct 2006 17:23:55 +0100, Andy Hall
wrote:

Thanks for the reply. It just occurred to me: scaling is only likely
to occur on the side of the heat exchanger that passes water from the
mains inlet to the sink taps, isn't it? In if that side was scaled up,
then there would be a reduction in flow from the hot taps, wouldn't
there?

Jim D

Possibly some, yes.

If the system is sludged, then a different course of action is needed -
basically clean it out and fill adding corrosion inhibitor to the
system afterwards

That's exactly what I did, a few days ago, just before this problem
started..

Jim D

Is it a sealed system or open vented with tank in the loft?

If it's the latter, then pumping over of heating water or sucking of
air into the system because the relative positions of pump,
feed/expansion and vent pipes can cause the water to become more
oxygenated than it otherwise would be. This effectively "uses up" the
inhibitor. You can diagnose this problem if the radiators need
frequent venting and the gas released is air and not hydrogen, or
pumping over can be seen from the vent pipe with the tank getting very
hot.

EIther way, I wonder if you have managed to flush some sludge into the
boiler....


Andy,

It's a closed, combi boiler system.

I have started a new thread called "Britony Combi 80 - symptoms
restated"... to list all the current symptoms in one place and in one
thread, for better clarity.

Thanks for your time,

Jim D

Andy Hall wrote:
On 2006-10-15 16:54:48 +0100, Jim D said:

On 15 Oct 2006 15:39:53 GMT, (Andrew
Gabriel) wrote:

I don't know this model, but why not descale it?

I descalled a friend's one from a Baxi using Furnox DS-3.
Dissolve some DS-3 in a large jug of hot water.
Stand the heat exchanger in a washing up bowl to catch
the descaller, and pour into the hot water side of the
heat exchanger slowly. Be prepared for violent descalling
spitting out the acid and acid spray. When you've poured
it all through, empty the heat exchanger out into the bowl,
transfer back to the jug, and the pour through again, until
the heat exchanger stops fizzing. If the descaller goes blue,
it's used up -- discard and mix up some fresh.

I did try descaling it once - but only with domestic supermarket
descaler. It fizzed and bubbled but didn't unblock it. I've never
tried "DS-3". Where can I obtain that in suitable quantities?

Plumbing and heating merchants have it in small and large tubs.


But I think these heat exchangers can also become blocked by rust and
sludge on the other side (non-tapwater) side of the exchanger, can't
they? That's what a corgi reg'd plumber once told me was wrong with
mine, anyway. He pointed oit the bits of black stuff inside the
exchanger and said "that's iron oxide that's blocking it" IIRC. Of
course, he might have been feeding me a line of s**t just to flog me
an overpriced heat-exchanger....

There's really no reason why a properly maintained heating system should
be suffering from sludge.

Actually there is.

And that is the water company is sending you sludge.

Personally I'd fi a water softener meself..and then claim against the
water company when their sludge blocks it.


If it is a sealed system (no header tank on loft) then the only action
that should be needed with a clean system is to dose it annually with
corrosion inhibitor - cost about £20.




Thanks,

Jim D

wrote in message ...
On 15 Oct,
Andy Hall wrote:

If it is a sealed system (no header tank on loft) then the only action
that should be needed with a clean system is to dose it annually with
corrosion inhibitor - cost about £20.

If it's a sealed system why dose annually? Once only should do (well
perhaps
every 10 years), unless you have a big leak.

Every 4 years.

"Jim D" wrote in message
...
On 15 Oct 2006 15:39:53 GMT, (Andrew
Gabriel) wrote:

I don't know this model, but why not descale it?

I descalled a friend's one from a Baxi using Furnox DS-3.
Dissolve some DS-3 in a large jug of hot water.
Stand the heat exchanger in a washing up bowl to catch
the descaller, and pour into the hot water side of the
heat exchanger slowly. Be prepared for violent descalling
spitting out the acid and acid spray. When you've poured
it all through, empty the heat exchanger out into the bowl,
transfer back to the jug, and the pour through again, until
the heat exchanger stops fizzing. If the descaller goes blue,
it's used up -- discard and mix up some fresh.

I did try descaling it once - but only with domestic supermarket
descaler. It fizzed and bubbled but didn't unblock it. I've never
tried "DS-3". Where can I obtain that in suitable quantities?

But I think these heat exchangers can also become blocked by rust and
sludge on the other side (non-tapwater) side of the exchanger, can't
they? That's what a corgi reg'd plumber once told me was wrong with
mine, anyway. He pointed oit the bits of black stuff inside the
exchanger and said "that's iron oxide that's blocking it" IIRC. Of
course, he might have been feeding me a line of s**t just to flog me
an overpriced heat-exchanger....

Clean the heat exchanger with DS3 as instructed. Use descaler in the CH
system after cleaning, drain, flush and fill with inhibitor. BUT!!!! add a
Magnaclean filter on the CH return pipe back to the boiler. That should
stop it happening again.