I'm looking to replace my old central heating boiler with a standard (i.e. 
not combi) condensing boiler. I will have it installed by a professional, 
but want to be more informed about available boilers rather than just accept 
what the heating engineer offers.

I have heard that the heat exchanger (HE) on condensing boilers can have a 
limited life, that cast iron HEs are to be avoided, aluminium are ok (ish) 
and that stainless steel HEs are best. Anyone have any views?

I've also heard that Potterton are unreliable (for condensing boilers) even 
though my old (non condensing) Potterton has served me well for nearly 35 
years!

Any other points tpo watch out for?

Does anyone have any recommendations (or otherwise) on makes/models of 
boilers?

Thanks, David.

On Mon, 22 Aug 2005 18:10:16 GMT, "DavidM" 
wrote:


>I'm looking to replace my old central heating boiler with a standard (i.e. 
>not combi) condensing boiler. I will have it installed by a professional, 
>but want to be more informed about available boilers rather than just accept 
>what the heating engineer offers.


Very wise.   People tend to fit what they know or whichever promo
programme is the best this month.


>
>I have heard that the heat exchanger (HE) on condensing boilers can have a 
>limited life, that cast iron HEs are to be avoided, aluminium are ok (ish) 
>and that stainless steel HEs are best. Anyone have any views?


That's basically it.



>
>I've also heard that Potterton are unreliable (for condensing boilers) even 
>though my old (non condensing) Potterton has served me well for nearly 35 
>years!


They are a shadow of their former selves.......



>
>Any other points tpo watch out for?
>
>Does anyone have any recommendations (or otherwise) on makes/models of 
>boilers?


Manufacturers in Germany and Holland have been making them for 15-20
years and are at 4th generation products in most cases.   Therefore
the better products are made in or are designs from these countries.

Typical good products:


- Vaillant
- Worcester-Bosch
- MAN
- Viessmann

Your installer may have heard of the first two.  The second two are
higher end.





>
>Thanks, David. 
>


-- 

..andy

To email, substitute .nospam with .gl

On Mon, 22 Aug 2005 18:10:16 GMT, "DavidM" 
wrote:


>I'm looking to replace my old central heating boiler with a standard (i.e. 
>not combi) condensing boiler. I will have it installed by a professional, 
>but want to be more informed about available boilers rather than just accept 
>what the heating engineer offers.


Very wise.   People tend to fit what they know or whichever promo
programme is the best this month.


>
>I have heard that the heat exchanger (HE) on condensing boilers can have a 
>limited life, that cast iron HEs are to be avoided, aluminium are ok (ish) 
>and that stainless steel HEs are best. Anyone have any views?


That's basically it.



>
>I've also heard that Potterton are unreliable (for condensing boilers) even 
>though my old (non condensing) Potterton has served me well for nearly 35 
>years!


They are a shadow of their former selves.......



>
>Any other points tpo watch out for?
>
>Does anyone have any recommendations (or otherwise) on makes/models of 
>boilers?


Manufacturers in Germany and Holland have been making them for 15-20
years and are at 4th generation products in most cases.   Therefore
the better products are made in or are designs from these countries.

Typical good products:


- Vaillant
- Worcester-Bosch
- MAN
- Viessmann

Your installer may have heard of the first two.  The second two are
higher end.





>
>Thanks, David. 
>


-- 

..andy

To email, substitute .nospam with .gl

DavidM wrote:


> I have heard that the heat exchanger (HE) on condensing boilers can have a 
> limited life, that cast iron HEs are to be avoided, aluminium are ok (ish) 
> and that stainless steel HEs are best. Anyone have any views?


I would go along with what you said... (ali heat exchangers ought to be 
fine if silicon coated).

Look for one with a single heat exchanger rather than one that has had a 
secondary one bolted on - this is usually an indication of an old design 
that has been updated to operate as a condensor rather than been 
designed that way from scratch.

Also look for a downward firing burner. This will prevent it being 
exposed to either as much soot or acidic condensate.


> I've also heard that Potterton are unreliable (for condensing boilers) even 
> though my old (non condensing) Potterton has served me well for nearly 35 
> years!


true sadly.


> Any other points tpo watch out for?


To comply with building regs you may have to upgrade your boiler 
controls, and fit a fast recovery cylinder if you don't already have 
one. You will need TRVs on all rads except the one in the room with the 
main stat. If the house is big you may need to zone the heating also.


> Does anyone have any recommendations (or otherwise) on makes/models of 
> boilers?


The ones Andy mentioned are usually very well regarded. Some of the ones 
from Ideal like the icos seem good as well.

-- 
Cheers,

John.

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

DavidM wrote:


> I have heard that the heat exchanger (HE) on condensing boilers can have a 
> limited life, that cast iron HEs are to be avoided, aluminium are ok (ish) 
> and that stainless steel HEs are best. Anyone have any views?


I would go along with what you said... (ali heat exchangers ought to be 
fine if silicon coated).

Look for one with a single heat exchanger rather than one that has had a 
secondary one bolted on - this is usually an indication of an old design 
that has been updated to operate as a condensor rather than been 
designed that way from scratch.

Also look for a downward firing burner. This will prevent it being 
exposed to either as much soot or acidic condensate.


> I've also heard that Potterton are unreliable (for condensing boilers) even 
> though my old (non condensing) Potterton has served me well for nearly 35 
> years!


true sadly.


> Any other points tpo watch out for?


To comply with building regs you may have to upgrade your boiler 
controls, and fit a fast recovery cylinder if you don't already have 
one. You will need TRVs on all rads except the one in the room with the 
main stat. If the house is big you may need to zone the heating also.


> Does anyone have any recommendations (or otherwise) on makes/models of 
> boilers?


The ones Andy mentioned are usually very well regarded. Some of the ones 
from Ideal like the icos seem good as well.

-- 
Cheers,

John.

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

"DavidM"  wrote in message 
news:cyoOe.1048$h4.143@newsfe4-win.ntli.net...

> I'm looking to replace my old central heating boiler with a standard (i.e. 
> not combi) condensing boiler. I will have it installed by a professional, 
> but want to be more informed about available boilers rather than just 
> accept what the heating engineer offers.
>
> I have heard that the heat exchanger (HE) on condensing boilers can have a 
> limited life, that cast iron HEs are to be avoided, aluminium are ok (ish) 
> and that stainless steel HEs are best. Anyone have any views?
>
> I've also heard that Potterton are unreliable (for condensing boilers) 
> even though my old (non condensing) Potterton has served me well for 
> nearly 35 years!
>
> Any other points tpo watch out for?
>
> Does anyone have any recommendations (or otherwise) on makes/models of 
> boilers?
>
> Thanks, David.
>

I have a cast iron cored boiler still plodding away after 30 odd years. It 
may be that the newer boilers are more efficient but this is generally 
achieved at the expense of longevity i.e. thinner (but more efficient heat 
exchanger cores), nevertheless with today's fuel prices a more efficient 
core may be preferable even if it is necessary to replace the boiler a 
little more often than would be otherwise needful. Condensing boilers have 
corrosion problems since parts of them are subject to "condensation", hence 
enhancing the corrosive effect of the flue gases.

I would doubt if even the stainless steel boilers are made with the heat 
exchanger from top grade materials and thus the rate of corrosion will only 
be slower than other cores and not zero.

Regards

Pilgarlick

"DavidM"  wrote in message 
news:cyoOe.1048$h4.143@newsfe4-win.ntli.net...

> I'm looking to replace my old central heating boiler with a standard (i.e. 
> not combi) condensing boiler. I will have it installed by a professional, 
> but want to be more informed about available boilers rather than just 
> accept what the heating engineer offers.
>
> I have heard that the heat exchanger (HE) on condensing boilers can have a 
> limited life, that cast iron HEs are to be avoided, aluminium are ok (ish) 
> and that stainless steel HEs are best. Anyone have any views?
>
> I've also heard that Potterton are unreliable (for condensing boilers) 
> even though my old (non condensing) Potterton has served me well for 
> nearly 35 years!
>
> Any other points tpo watch out for?
>
> Does anyone have any recommendations (or otherwise) on makes/models of 
> boilers?
>
> Thanks, David.
>

I have a cast iron cored boiler still plodding away after 30 odd years. It 
may be that the newer boilers are more efficient but this is generally 
achieved at the expense of longevity i.e. thinner (but more efficient heat 
exchanger cores), nevertheless with today's fuel prices a more efficient 
core may be preferable even if it is necessary to replace the boiler a 
little more often than would be otherwise needful. Condensing boilers have 
corrosion problems since parts of them are subject to "condensation", hence 
enhancing the corrosive effect of the flue gases.

I would doubt if even the stainless steel boilers are made with the heat 
exchanger from top grade materials and thus the rate of corrosion will only 
be slower than other cores and not zero.

Regards

Pilgarlick

Pilgarlick wrote:


> little more often than would be otherwise needful. Condensing boilers have 
> corrosion problems since parts of them are subject to "condensation", hence 
> enhancing the corrosive effect of the flue gases.


More correctly -poorly designed condensing boilers suffer corrosian 
problems. A well designed one will use materials that are not affected 
by the (mild) acidity of the condensate, and a layout that places 
critical parts out of the path of any collecting or falling condensate 
(downward firing burners etc).


-- 
Cheers,

John.

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

Pilgarlick wrote:


> little more often than would be otherwise needful. Condensing boilers have 
> corrosion problems since parts of them are subject to "condensation", hence 
> enhancing the corrosive effect of the flue gases.


More correctly -poorly designed condensing boilers suffer corrosian 
problems. A well designed one will use materials that are not affected 
by the (mild) acidity of the condensate, and a layout that places 
critical parts out of the path of any collecting or falling condensate 
(downward firing burners etc).


-- 
Cheers,

John.

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

"Andy Hall" <andyh@hall.nospam> wrote in message 
news:dr8kg1p5e4mg9unrat3riqkgr70aabpifc@4ax.com...

> On Mon, 22 Aug 2005 18:10:16 GMT, "DavidM" 
> wrote:
>
>>I'm looking to replace my old central heating boiler with a standard (i.e.
>>not combi) condensing boiler. I will have it installed by a professional,
>>but want to be more informed about available boilers rather than just 
>>accept
>>what the heating engineer offers.
>
> Very wise.   People tend to fit what they know or whichever promo
> programme is the best this month.
>
>>
>>I have heard that the heat exchanger (HE) on condensing boilers can have a
>>limited life, that cast iron HEs are to be avoided, aluminium are ok (ish)
>>and that stainless steel HEs are best. Anyone have any views?
>
> That's basically it.
>


A lot of the newer Aluminium heat exchangers are coated to protect the 
substrate metal. Works fine as long as the coating is not scratched. Once it 
has been damaged then you are wide open to corrosion. Stainless Steel is the 
way to go in my book

"Andy Hall" <andyh@hall.nospam> wrote in message 
news:dr8kg1p5e4mg9unrat3riqkgr70aabpifc@4ax.com...

> On Mon, 22 Aug 2005 18:10:16 GMT, "DavidM" 
> wrote:
>
>>I'm looking to replace my old central heating boiler with a standard (i.e.
>>not combi) condensing boiler. I will have it installed by a professional,
>>but want to be more informed about available boilers rather than just 
>>accept
>>what the heating engineer offers.
>
> Very wise.   People tend to fit what they know or whichever promo
> programme is the best this month.
>
>>
>>I have heard that the heat exchanger (HE) on condensing boilers can have a
>>limited life, that cast iron HEs are to be avoided, aluminium are ok (ish)
>>and that stainless steel HEs are best. Anyone have any views?
>
> That's basically it.
>


A lot of the newer Aluminium heat exchangers are coated to protect the 
substrate metal. Works fine as long as the coating is not scratched. Once it 
has been damaged then you are wide open to corrosion. Stainless Steel is the 
way to go in my book