Is it possible to use some chemical to remove limescale from the inside of a
direct hot water heat exchanger from a combi boiler or is it a case of
replacement?

Keith D wrote:

Is it possible to use some chemical to remove limescale from the inside of a
direct hot water heat exchanger from a combi boiler or is it a case of
replacement?

I seem to recall someone on this group having some success pouring
through a concentrated solution of Fernox DS3...

Can't hurt trying can it?

--
Cheers,

John.

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John Rumm wrote:
Keith D wrote:

Is it possible to use some chemical to remove limescale from the
inside of a direct hot water heat exchanger from a combi boiler or
is it a case of replacement?

I seem to recall someone on this group having some success pouring
through a concentrated solution of Fernox DS3...

Can't hurt trying can it?

'cept when it burns through the diaphgram and leaks into the bath/sink/kettle

( has happened )

.. wrote:

Can't hurt trying can it?


'cept when it burns through the diaphgram and leaks into the bath/sink/kettle

( has happened )

Still no more bu**ered though is it? ;-)

--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

John Rumm wrote:
. wrote:

Can't hurt trying can it?


'cept when it burns through the diaphgram and leaks into the
bath/sink/kettle

( has happened )

Still no more bu**ered though is it? ;-)

yes, goes from an operable system to one that's a callback.

on a sat afternoon, owner with 3 small kids. no engineers
available for 50 miles or 2 days... BiL responsible ....

"Keith D" wrote in message
...
Is it possible to use some chemical to remove limescale from the inside of
a direct hot water heat exchanger from a combi boiler or is it a case of
replacement?

http://www.kamco.co.uk/scalebreaker.htm

On Wed, 08 Mar 2006 18:12:55 +0000, Keith D wrote:

Is it possible to use some chemical to remove limescale from the inside of a
direct hot water heat exchanger from a combi boiler or is it a case of
replacement?

Yes, there is a small risk that the unit will then leak between the
primary and domestic sides.
Suggest dilute HCl - available as brickwork cleaner from Builders
Merchants.

--
Ed Sirett - Property maintainer and registered gas fitter.
The FAQ for uk.diy is at http://www.diyfaq.org.uk
Gas fitting FAQ http://www.makewrite.demon.co.uk/GasFitting.html
Sealed CH FAQ http://www.makewrite.demon.co.uk/SealedCH.html
Choosing a Boiler FAQ http://www.makewrite.demon.co.uk/BoilerChoice.html

In article ,
"." writes:
John Rumm wrote:
Keith D wrote:

Is it possible to use some chemical to remove limescale from the
inside of a direct hot water heat exchanger from a combi boiler or
is it a case of replacement?

I seem to recall someone on this group having some success pouring
through a concentrated solution of Fernox DS3...

Me, probably. Worked fine.

Can't hurt trying can it?

'cept when it burns through the diaphgram and leaks into the bath/sink/kettle

Eh? You will be running it through that side anyway.

--
Andrew Gabriel

In message , .
writes
John Rumm wrote:
Keith D wrote:

Is it possible to use some chemical to remove limescale from the
inside of a direct hot water heat exchanger from a combi boiler or
is it a case of replacement?

I seem to recall someone on this group having some success pouring
through a concentrated solution of Fernox DS3...

Can't hurt trying can it?

'cept when it burns through the diaphgram and leaks into the
bath/sink/kettle

Which is, of course, irrelevant if you connect directly up to the heat
exch, as you seemed to be inferring



--
geoff

In message , Keith D
writes
Is it possible to use some chemical to remove limescale from the inside of a
direct hot water heat exchanger from a combi boiler or is it a case of
replacement?

What you really want is a descaling pump, but pouring a descaler in and
agitating it will work to an extent

http://www.kamco.co.uk/descalinginstructions.htm

might be useful for you to take a look at

Where are you ? I have a descaling pump


--
geoff

On Wed, 08 Mar 2006 22:44:56 GMT, raden wrote:

In message , Keith D
writes
Is it possible to use some chemical to remove limescale from the inside of a
direct hot water heat exchanger from a combi boiler or is it a case of
replacement?

What you really want is a descaling pump, but pouring a descaler in and
agitating it will work to an extent

http://www.kamco.co.uk/descalinginstructions.htm

might be useful for you to take a look at

Where are you ? I have a descaling pump

You could also make up a fairly decent diy version of that using one
of those cheap drill powered liquid pumps and a bucket for the
descaler.

In message , EricP
writes
On Wed, 08 Mar 2006 22:44:56 GMT, raden wrote:

In message , Keith D
writes
Is it possible to use some chemical to remove limescale from the inside of a
direct hot water heat exchanger from a combi boiler or is it a case of
replacement?

What you really want is a descaling pump, but pouring a descaler in and
agitating it will work to an extent

http://www.kamco.co.uk/descalinginstructions.htm

might be useful for you to take a look at

Where are you ? I have a descaling pump

You could also make up a fairly decent diy version of that using one
of those cheap drill powered liquid pumps and a bucket for the
descaler.

As long as you were expecting the pump to be "single use"

HCl or Phosphoric acid or whatever can be fairly aggressive


--
geoff

"EricP" wrote in message
...
On Wed, 08 Mar 2006 22:44:56 GMT, raden wrote:

In message , Keith D
writes
Is it possible to use some chemical to remove limescale from the inside
of a
direct hot water heat exchanger from a combi boiler or is it a case of
replacement?

What you really want is a descaling pump, but pouring a descaler in and
agitating it will work to an extent

http://www.kamco.co.uk/descalinginstructions.htm

might be useful for you to take a look at

Where are you ? I have a descaling pump

You could also make up a fairly decent diy version of that using one
of those cheap drill powered liquid pumps and a bucket for the
descaler.

If descaling a heat bank. the plate can be reversed, chemicals put in the
heat bank, and run the DHW pump. Drain the cylinder, flush and fill with
inhibitor.

On Thu, 9 Mar 2006 00:48:57 -0000, "Doctor Drivel"
wrote:


"EricP" wrote in message
.. .
On Wed, 08 Mar 2006 22:44:56 GMT, raden wrote:

In message , Keith D
writes
Is it possible to use some chemical to remove limescale from the inside
of a
direct hot water heat exchanger from a combi boiler or is it a case of
replacement?

What you really want is a descaling pump, but pouring a descaler in and
agitating it will work to an extent

http://www.kamco.co.uk/descalinginstructions.htm

might be useful for you to take a look at

Where are you ? I have a descaling pump

You could also make up a fairly decent diy version of that using one
of those cheap drill powered liquid pumps and a bucket for the
descaler.

If descaling a heat bank. the plate can be reversed, chemicals put in the
heat bank, and run the DHW pump. Drain the cylinder, flush and fill with
inhibitor.


This would need quite a lot of descaling chemical however. You would
be dissolving it in (say) 100 litres of water rather than perhaps 5.


--

..andy

In article ,
raden writes:
In message , Keith D
writes
Is it possible to use some chemical to remove limescale from the inside of a
direct hot water heat exchanger from a combi boiler or is it a case of
replacement?

What you really want is a descaling pump, but pouring a descaler in and
agitating it will work to an extent

I stood the thing in a washing up bowl, and poured the descaler
in one of the holes from a pint jug. The bowl collected the waste
as it emerged. The descaler could be recycled about 3 times before
it was spent (easy to tell with Furnox DS-3 as it changes colour).
I had to perform this whole process about 3 times (i.e. about 3
pints of descaler) to dissolve all the scale. The small size of
plate exchangers is quite deceptive, but they have a large surface
area which can hold a lot of scale, vastly more than a kettle (so
don't bother trying to do it with one sachet of kettle descaler).

Whilst you have the plate exchanger out, give the central heating
water side a good flush through with water too. The plate exchanger
can act as the system's filter, trapping any small bits of debris
floating around.

--
Andrew Gabriel

"Andrew Gabriel" wrote in message
...
In article ,
raden writes:
In message , Keith D
writes
Is it possible to use some chemical to remove limescale from the inside
of a
direct hot water heat exchanger from a combi boiler or is it a case of
replacement?

What you really want is a descaling pump, but pouring a descaler in and
agitating it will work to an extent

I stood the thing in a washing up bowl, and poured the descaler
in one of the holes from a pint jug. The bowl collected the waste
as it emerged. The descaler could be recycled about 3 times before
it was spent (easy to tell with Furnox DS-3 as it changes colour).
I had to perform this whole process about 3 times (i.e. about 3
pints of descaler) to dissolve all the scale. The small size of
plate exchangers is quite deceptive, but they have a large surface
area which can hold a lot of scale, vastly more than a kettle (so
don't bother trying to do it with one sachet of kettle descaler).

Whilst you have the plate exchanger out, give the central heating
water side a good flush through with water too. The plate exchanger
can act as the system's filter, trapping any small bits of debris
floating around.

Firstly a filter should always be fitted on the return to a boiler,
especially a combi, then no crud or debis fed into the plate heat exchnager
or main heat exchanger. Magnaclean comes to mind in a boiler change; they
are highly effective. By using pipe fittings and hose pipes you can use
mains water to flush out the plate. The makers always recommend to feed the
water in, in the reverse direction. This alone can dislodge much scale.

"Andy Hall" aka Matt wrote in message
...
On Thu, 9 Mar 2006 00:48:57 -0000, "Doctor Drivel"
wrote:


"EricP" wrote in message
. ..
On Wed, 08 Mar 2006 22:44:56 GMT, raden wrote:

In message , Keith D
writes
Is it possible to use some chemical to remove limescale from the inside
of a
direct hot water heat exchanger from a combi boiler or is it a case of
replacement?

What you really want is a descaling pump, but pouring a descaler in and
agitating it will work to an extent

http://www.kamco.co.uk/descalinginstructions.htm

might be useful for you to take a look at

Where are you ? I have a descaling pump

You could also make up a fairly decent diy version of that using one
of those cheap drill powered liquid pumps and a bucket for the
descaler.

If descaling a heat bank. the plate
can be reversed, chemicals put in the
heat bank, and run the DHW pump.
Drain the cylinder, flush and fill with
inhibitor.

This would need quite a lot of descaling chemical however. You would
be dissolving it in (say) 100 litres of water rather than perhaps 5.

Matt, yes. But it saves a fortune on a descaling pump. Have isolation
valves around the plate and both sides of the plate can be treated all with
the same solution.

On Wed, 08 Mar 2006 20:26:05 +0000, Ed Sirett wrote:

On Wed, 08 Mar 2006 18:12:55 +0000, Keith D wrote:

Is it possible to use some chemical to remove limescale from the inside of a
direct hot water heat exchanger from a combi boiler or is it a case of
replacement?

Yes, there is a small risk that the unit will then leak between the
primary and domestic sides.
Suggest dilute HCl - available as brickwork cleaner from Builders
Merchants.

I've used that with success, pumping through with a garden sprayer and
putting the used dilute acid back in the sprayer bottle to pump through
again, testing by chucking a bit of bicarb in and seeing if it fizzes,
adding more HCL as necessary. Took all day though. For the next one I'll
try to get the heat exchanger out and use Kilrock (formic acid) which
seems better at dissolving limescale (and is recommended for such jobs)

On Thu, 09 Mar 2006 15:54:23 +0000, John Stumbles wrote:

On Wed, 08 Mar 2006 20:26:05 +0000, Ed Sirett wrote:

On Wed, 08 Mar 2006 18:12:55 +0000, Keith D wrote:

Is it possible to use some chemical to remove limescale from the inside of a
direct hot water heat exchanger from a combi boiler or is it a case of
replacement?

Yes, there is a small risk that the unit will then leak between the
primary and domestic sides.
Suggest dilute HCl - available as brickwork cleaner from Builders
Merchants.

I've used that with success, pumping through with a garden sprayer and
putting the used dilute acid back in the sprayer bottle to pump through
again, testing by chucking a bit of bicarb in and seeing if it fizzes,
adding more HCL as necessary. Took all day though. For the next one I'll
try to get the heat exchanger out and use Kilrock (formic acid) which
seems better at dissolving limescale (and is recommended for such jobs)

I had assumed that the unit was already removed.


--
Ed Sirett - Property maintainer and registered gas fitter.
The FAQ for uk.diy is at http://www.diyfaq.org.uk
Gas fitting FAQ http://www.makewrite.demon.co.uk/GasFitting.html
Sealed CH FAQ http://www.makewrite.demon.co.uk/SealedCH.html
Choosing a Boiler FAQ http://www.makewrite.demon.co.uk/BoilerChoice.html

On Thu, 09 Mar 2006 15:54:23 +0000, John Stumbles wrote:

I've used that with success, pumping through with a garden sprayer and
putting the used dilute acid back in the sprayer bottle to pump through
again, testing by chucking a bit of bicarb in and seeing if it fizzes,
adding more HCL as necessary. Took all day though. For the next one I'll
try to get the heat exchanger out and use Kilrock (formic acid) which
seems better at dissolving limescale (and is recommended for such jobs)

I've done the next one now and about 2 hours and about a pint of kilrock
got it all flowing nicely. I'm sure it's not 100% descaled but I had other
stuff to get on with there, and I've got to go back to fit a scale
inhibitor anyway so I'll probably give it a second helping then.

There was no way[1] I could get the heat exchanger out but it was easy
to pump in the kilrock via the filling loop supply valve and out
again by a washing machine hot valve (or I could have used the kit sink
hot tap) so I did it in situ. The descaler working its way through the
pipework to the other taps etc was probably no bad thing either! It's a
bit of a pain tipping it back from the bucket into the sprayer and pumping
it up again though: I think I'll look at one of those small submersible
water-feature pumps with all-plastic & ceramic impellers etc next time.
Unlike power-flushing I reckon you don't need much flow: just enough to
keep fresh descaler moving through the works.


[1]to a first approximation: numpty had boxed in the boiler with umpteen
screwed panels etc and I CBA to dismantle it all.