Hi all,
I want to install a phosphate doser into my new central heating system (to
reduce combi-boiler maintenance costs). Can anyone recommend one that is
inexpensive, and which will probably be cheap to refill for years to come?

Many thanks,

A

On 21/10/2012 19:15, Alibaba wrote:
Hi all,
I want to install a phosphate doser into my new central heating system (to
reduce combi-boiler maintenance costs). Can anyone recommend one that is
inexpensive, and which will probably be cheap to refill for years to come?

I had to make a similar decision recently, and in the end went for:

http://www.screwfix.com/p/1-stage-wh...n-system/20315

There is also a 15mm pipe version which would be adequate for a combi:

http://www.screwfix.com/p/polyphosph...nhibitor/68371

(not sure if there is any benefit to that one given its more expensive!)

--
Cheers,

John.

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

John Rumm wrote in
o.uk:


http://www.screwfix.com/p/polyphosph...nhibitor/68371

Hi John,
Thanks for the tip. Do you have to buy a 'cartridge' for that model, when
it runs out? I had a vague idea that some phosphate dosers can be refilled
with generic phosphate balls (which would be useful if the cartridge-maker
goes bust).

A

On 21/10/2012 20:05, Alibaba wrote:
John Rumm wrote in
o.uk:


http://www.screwfix.com/p/polyphosph...nhibitor/68371

Hi John,
Thanks for the tip. Do you have to buy a 'cartridge' for that model, when
it runs out? I had a vague idea that some phosphate dosers can be refilled
with generic phosphate balls (which would be useful if the cartridge-maker
goes bust).

Yup that one takes a cartridge.

Some like the Combimate, take balls loose. But having had one of those
in the past I was less impressed with it. (more of a hassle to top up,
restricted flow a bit more, and rattled a tad in use). They are also
quite pricey.

There is a moderate chance you could refill one of the BWS cartridges if
needs be.


--
Cheers,

John.

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

On Oct 21, 7:15*pm, Alibaba wrote:
Hi all,
I want to install a phosphate doser into my new central heating system (to
reduce combi-boiler maintenance costs). Can anyone recommend one that is
inexpensive, and which will probably be cheap to refill for years to come?

Many thanks,

A

Why not get a water softener and all you need then is salt?

harry wrote in news:56002e72-ef88-4af1-bac1-
:

Why not get a water softener and all you need then is salt?

That's an idea; thanks. I've just been searching for a conversation I had
about this subject a few years ago, and there was a heated (and
inconclusive) debate about whether phosphate dosers and water softeners
were more effective than ion exchange water softeners. No-one involved in
the discussion could point to any controlled tests to back up their
opinions. Anyone got any educated (or fist-hand experience) opinions on
this question?

In a previous house, I installed a phosphate doser, thinking it would
prevent my heat exchanger from scaling up. One year later my boiler's
heat exchanger was clogged again, as it had done almost every year
previously. Having said that, I think it was partly clogged with iron
oxide (i.e., black rust). Perhaps water softeners don't inhibit the
formation of iron oxide. Is there anything that inhibits the formation of
iron oxide, as well as limescale, in heat exchangers (apart from things
like Fernox, which obviously can't be added to mains drinking water.

A

On 25/10/2012 13:21, Alibaba wrote:
harry wrote in news:56002e72-ef88-4af1-bac1-
:

Why not get a water softener and all you need then is salt?

That's an idea; thanks. I've just been searching for a conversation I had
about this subject a few years ago, and there was a heated (and
inconclusive) debate about whether phosphate dosers and water softeners
were more effective than ion exchange water softeners. No-one involved in
the discussion could point to any controlled tests to back up their
opinions. Anyone got any educated (or fist-hand experience) opinions on
this question?

A phosphate dosing unit won't soften the water. It will stop the scale
precipitation out when its heated, but let the water dry on a surface
and it will still leave marks etc.

In a previous house, I installed a phosphate doser, thinking it would
prevent my heat exchanger from scaling up. One year later my boiler's
heat exchanger was clogged again, as it had done almost every year
previously. Having said that, I think it was partly clogged with iron
oxide (i.e., black rust).

It could clog with iron oxide on the primary side of the HE. There
should be none in the HW side. But that would be a separate problem
caused by corrosion in the heating system.

Perhaps water softeners don't inhibit the
formation of iron oxide. Is there anything that inhibits the formation of
iron oxide, as well as limescale, in heat exchangers (apart from things
like Fernox, which obviously can't be added to mains drinking water.

The primary side, can be dosed with inhibitor like Fernox - you will not
be drinking that. The HW side of the exchanger can be protected from
scale by the phosphate unit. Unless there is something odd about your
local water supply, there should be no iron oxide in that. If that is
proving to be a problem then you need a particulate filter on the cold
supply (BWS do a matching unit with a cartridge for that - you can get
them as a pair from SF)

--
Cheers,

John.

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

John Rumm wrote in
o.uk:

On 25/10/2012 13:21, Alibaba wrote:
harry wrote in
news:56002e72-ef88-4af1-bac1-
:

Why not get a water softener and all you need then is salt?

That's an idea; thanks. I've just been searching for a conversation I
had about this subject a few years ago, and there was a heated (and
inconclusive) debate about whether phosphate dosers and water
softeners were more effective than ion exchange water softeners.
No-one involved in the discussion could point to any controlled tests
to back up their opinions. Anyone got any educated (or fist-hand
experience) opinions on this question?

A phosphate dosing unit won't soften the water. It will stop the scale
precipitation out when its heated, but let the water dry on a surface
and it will still leave marks etc.

In a previous house, I installed a phosphate doser, thinking it would
prevent my heat exchanger from scaling up. One year later my boiler's
heat exchanger was clogged again, as it had done almost every year
previously. Having said that, I think it was partly clogged with iron
oxide (i.e., black rust).

It could clog with iron oxide on the primary side of the HE. There
should be none in the HW side. But that would be a separate problem
caused by corrosion in the heating system.

Perhaps water softeners don't inhibit the
formation of iron oxide. Is there anything that inhibits the
formation of iron oxide, as well as limescale, in heat exchangers
(apart from things like Fernox, which obviously can't be added to
mains drinking water.

The primary side, can be dosed with inhibitor like Fernox - you will
not be drinking that. The HW side of the exchanger can be protected
from scale by the phosphate unit. Unless there is something odd about
your local water supply, there should be no iron oxide in that. If
that is proving to be a problem then you need a particulate filter on
the cold supply (BWS do a matching unit with a cartridge for that -
you can get them as a pair from SF)


John, Thanks for the clarification. Thinking back, I think my hot water
taps were delivering luke warm water, which, as you point out, suggests
it was the primary side that got blocked with the iron oxide, thus
stopping the heat getting to the tapwater.

Yes, now that you've helped to clarify that, I see that my phospate doser
would not have been responsible for that.

So the only real question now seems to be whether to install a phosphate
doser, a salt-filled water softener or an ion-exchange water softener.

You seem to favour phosphate dosers, yes?

Regards,
A

On 26/10/2012 19:42, Al N wrote:

The primary side, can be dosed with inhibitor like Fernox - you will
not be drinking that. The HW side of the exchanger can be protected
from scale by the phosphate unit. Unless there is something odd about
your local water supply, there should be no iron oxide in that. If
that is proving to be a problem then you need a particulate filter on
the cold supply (BWS do a matching unit with a cartridge for that -
you can get them as a pair from SF)


John, Thanks for the clarification. Thinking back, I think my hot water
taps were delivering luke warm water, which, as you point out, suggests
it was the primary side that got blocked with the iron oxide, thus
stopping the heat getting to the tapwater.

Well you could have poor heat transfer from primary to secondary sides
of the HE because the primary side was blocked by black iron crud, or
the secondary side was furred up with limescale[1]. So you can get a
similar symptom from two different problems with different causes and
solutions.

[1] You may also get reduced flow rate from that as well, but since most
common combis can't heat big flow rates in the first place, you are
probably less likely to notice that in real life.

Yes, now that you've helped to clarify that, I see that my phospate doser
would not have been responsible for that.

So the only real question now seems to be whether to install a phosphate
doser, a salt-filled water softener or an ion-exchange water softener.

"salt-filled water softener" and ion exchange are one and the same thing
IIUC. The salt is used to make a brine solution that is used to flush
and "charge" a resin matrix with sodium ions. The fresh water then
passes through the matrix where the calcium/magnesium etc ions in the
water are attracted to the matrix, and the sodium ions in it are
attracted to the water. Hence one set of ions gets swapped for another.
(and contrary to popular expectation, the salt is not not added to the
domestic water - its just used for the flushing process)

You seem to favour phosphate dosers, yes?

Favour would be the wrong word - they do different things (well one is a
reasonable subset of the others).

There is also a big difference in installation cost (although you may
find the effects of a real softener will eventually pay for themselves
in reduced detergent use etc).

Whether you want to go for fully softened water will depend a bit on
what you want to achieve and why. Some folks are not keen on soft water,
anyway - although if you are softening a naturally hard supply, then at
least you have the option of using it "raw" as well for drinking etc.




--
Cheers,

John.

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

John Rumm wrote in
o.uk:

On 26/10/2012 19:42, Al N wrote:

The primary side, can be dosed with inhibitor like Fernox - you will
not be drinking that. The HW side of the exchanger can be protected
from scale by the phosphate unit. Unless there is something odd
about your local water supply, there should be no iron oxide in
that. If that is proving to be a problem then you need a particulate
filter on the cold supply (BWS do a matching unit with a cartridge
for that - you can get them as a pair from SF)


John, Thanks for the clarification. Thinking back, I think my hot
water taps were delivering luke warm water, which, as you point out,
suggests it was the primary side that got blocked with the iron
oxide, thus stopping the heat getting to the tapwater.

Well you could have poor heat transfer from primary to secondary sides
of the HE because the primary side was blocked by black iron crud, or
the secondary side was furred up with limescale[1]. So you can get a
similar symptom from two different problems with different causes and
solutions.

[1] You may also get reduced flow rate from that as well, but since
most common combis can't heat big flow rates in the first place, you
are probably less likely to notice that in real life.

Yes, now that you've helped to clarify that, I see that my phospate
doser would not have been responsible for that.

So the only real question now seems to be whether to install a
phosphate doser, a salt-filled water softener or an ion-exchange
water softener.

"salt-filled water softener" and ion exchange are one and the same
thing IIUC. The salt is used to make a brine solution that is used to
flush and "charge" a resin matrix with sodium ions. The fresh water
then passes through the matrix where the calcium/magnesium etc ions in
the water are attracted to the matrix, and the sodium ions in it are
attracted to the water. Hence one set of ions gets swapped for
another. (and contrary to popular expectation, the salt is not not
added to the domestic water - its just used for the flushing process)

You seem to favour phosphate dosers, yes?

Favour would be the wrong word - they do different things (well one is
a reasonable subset of the others).

There is also a big difference in installation cost (although you may
find the effects of a real softener will eventually pay for themselves
in reduced detergent use etc).

Whether you want to go for fully softened water will depend a bit on
what you want to achieve and why. Some folks are not keen on soft
water, anyway - although if you are softening a naturally hard supply,
then at least you have the option of using it "raw" as well for
drinking etc.

Many thanks for your help. Yes, I am in a *very* hard water area. My
primary reason for wanting softened water is just to stop the heat
achangers furring up. Saving money on detergents, shampoo, etc.,
certainly sounds appealling.

A

On 27/10/2012 17:04, Al N wrote:
John Rumm wrote in
o.uk:

On 26/10/2012 19:42, Al N wrote:

The primary side, can be dosed with inhibitor like Fernox - you will
not be drinking that. The HW side of the exchanger can be protected
from scale by the phosphate unit. Unless there is something odd
about your local water supply, there should be no iron oxide in
that. If that is proving to be a problem then you need a particulate
filter on the cold supply (BWS do a matching unit with a cartridge
for that - you can get them as a pair from SF)


John, Thanks for the clarification. Thinking back, I think my hot
water taps were delivering luke warm water, which, as you point out,
suggests it was the primary side that got blocked with the iron
oxide, thus stopping the heat getting to the tapwater.

Well you could have poor heat transfer from primary to secondary sides
of the HE because the primary side was blocked by black iron crud, or
the secondary side was furred up with limescale[1]. So you can get a
similar symptom from two different problems with different causes and
solutions.

[1] You may also get reduced flow rate from that as well, but since
most common combis can't heat big flow rates in the first place, you
are probably less likely to notice that in real life.

Yes, now that you've helped to clarify that, I see that my phospate
doser would not have been responsible for that.

So the only real question now seems to be whether to install a
phosphate doser, a salt-filled water softener or an ion-exchange
water softener.

"salt-filled water softener" and ion exchange are one and the same
thing IIUC. The salt is used to make a brine solution that is used to
flush and "charge" a resin matrix with sodium ions. The fresh water
then passes through the matrix where the calcium/magnesium etc ions in
the water are attracted to the matrix, and the sodium ions in it are
attracted to the water. Hence one set of ions gets swapped for
another. (and contrary to popular expectation, the salt is not not
added to the domestic water - its just used for the flushing process)

You seem to favour phosphate dosers, yes?

Favour would be the wrong word - they do different things (well one is
a reasonable subset of the others).

There is also a big difference in installation cost (although you may
find the effects of a real softener will eventually pay for themselves
in reduced detergent use etc).

Whether you want to go for fully softened water will depend a bit on
what you want to achieve and why. Some folks are not keen on soft
water, anyway - although if you are softening a naturally hard supply,
then at least you have the option of using it "raw" as well for
drinking etc.

Many thanks for your help. Yes, I am in a *very* hard water area. My
primary reason for wanting softened water is just to stop the heat
achangers furring up. Saving money on detergents, shampoo, etc.,
certainly sounds appealling.

Soft will do that. On the down side, it can be its harder to rinse, and
can be a bit more aggressive on plumbing fittings in other ways. They
waste a certain amount of water in the recharge cycle, and you need to
remember to fill them up. Depending on the type you go for (one tank or
two) you may also get moments where it can't keep up with delivery from
the prepared softened water. Lastly they fill a reasonable amount of
space, so you need somewhere to site one. So if going that route, read
up on the types and features before making a decision.


--
Cheers,

John.

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

John Rumm wrote in
o.uk:


Many thanks for your help. Yes, I am in a *very* hard water area. My
primary reason for wanting softened water is just to stop the heat
achangers furring up. Saving money on detergents, shampoo, etc.,
certainly sounds appealling.

Soft will do that. On the down side, it can be its harder to rinse, and
can be a bit more aggressive on plumbing fittings in other ways. They
waste a certain amount of water in the recharge cycle, and you need to
remember to fill them up. Depending on the type you go for (one tank or
two) you may also get moments where it can't keep up with delivery from
the prepared softened water. Lastly they fill a reasonable amount of
space, so you need somewhere to site one. So if going that route, read
up on the types and features before making a decision.


I will do that. Thanks again!
A