I posted recently asking about "descalers" for combi boilers.

I spoke to my friend who has pretty much decided to get a "Fernox
Quantomat". From what I can see it's suitable for whole house use as
well as protecting the boiler.

What are the advantages to protecting the whole house instead of just
the boiler? Scale build up only occurs on the hot side so is there any
point protecting the cold water circuit?

Obvious disadvantages are that it'll cost more and the family will be
drinking water with phosphates in it.

(fwiw, he's never had any problems with appliances scaling up.)

Unless anyone can see an advantage to whole house protection I'll
recommend fitting it to the boiler only.

sponix

Sponix wrote:

What are the advantages to protecting the whole house instead of just
the boiler? Scale build up only occurs on the hot side so is there any
point protecting the cold water circuit?

Limited in my experiance - it only has a big effect on scale
precipitated out during heating. Since it does not soften the water the
scale is still present in it and will be left on surfaces when the water
evaporates. You may find that it reduces scale a little - but you will
still get it on hard surfaces etc.

Remember however that many dishwashers etc will fill from the cold and
do their own heating - so for that reason it is probably worth treating
the whole house supply.

Obvious disadvantages are that it'll cost more and the family will be
drinking water with phosphates in it.

Things like the combimate use food grade phosphates and only add tiny
amounts... they are not that expensive to run anyway - but you may want
to avoid feeding the outside tap since that is where you may use a
significant amount of cold water.


--
Cheers,

John.

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On Wed, 22 Feb 2006 04:03:25 +0000, John Rumm
wrote:

Sponix wrote:

What are the advantages to protecting the whole house instead of just
the boiler? Scale build up only occurs on the hot side so is there any
point protecting the cold water circuit?

Limited in my experiance - it only has a big effect on scale
precipitated out during heating. Since it does not soften the water the
scale is still present in it and will be left on surfaces when the water
evaporates. You may find that it reduces scale a little - but you will
still get it on hard surfaces etc.

From what I can gather it simply coats the insides of the pipes with
phosphate which stops the scale from sticking. The scale is still
there but doesn't stick.

Apparently some soft water areas have phosphate added by the water
board. It coats the inside of lead pipes and stops the lead getting
into the water...

Remember however that many dishwashers etc will fill from the cold and
do their own heating - so for that reason it is probably worth treating
the whole house supply.

It's never been a major problem from what I can gather. Appliances
have failed for other reasons long before the scale has an effect.

Obvious disadvantages are that it'll cost more and the family will be
drinking water with phosphates in it.

Things like the combimate use food grade phosphates and only add tiny
amounts... they are not that expensive to run anyway - but you may want
to avoid feeding the outside tap since that is where you may use a
significant amount of cold water.

Cost isn't an issue. What could cause problems is forgetting to check
the device isn't empty!

sponix