I've recently had an extension built with a new Glow Worm 30ci combi
boiler fitted.

There is a little old pipework remaining and one small rad otherwise
the system is new.

My previous gravity system gave no trouble, apart from the occasional
pump, it worked faultlessly but owing to a need for instant hot water
I went for a combi.

After 16 months the secondary heat exchanger failed, as I had not had
the apparently mandatory service this was not covered by warranty so I
had a very expensive repair.

The service engineer said this was due to the system not being flushed
as the heat exchanger was blocked.

I am now led to believe that system flushing appears to be a necessary
requirement for combis due to the design, how important is this
flushing, I would have thought any modern boiler should have some
filtering system to prevent fouling of the internals.

Geoff Lane

In article ,
Geoff Lane writes:
I've recently had an extension built with a new Glow Worm 30ci combi
boiler fitted.

There is a little old pipework remaining and one small rad otherwise
the system is new.

My previous gravity system gave no trouble, apart from the occasional
pump, it worked faultlessly but owing to a need for instant hot water
I went for a combi.

After 16 months the secondary heat exchanger failed, as I had not had
the apparently mandatory service this was not covered by warranty so I
had a very expensive repair.

The service engineer said this was due to the system not being flushed
as the heat exchanger was blocked.

Which side blocked? If you are in a hard water area, you can
expect the secondary side to scale up. I recently descalled
a friend's one in Baxi 105, but that took 4 years to block,
with a family of 5 including two babies.

I am now led to believe that system flushing appears to be a necessary
requirement for combis due to the design, how important is this
flushing, I would have thought any modern boiler should have some
filtering system to prevent fouling of the internals.

There shouldn't be any new debris appearing in the heating
circuit in the first place (at least not within 16 months).

--
Andrew Gabriel

"Andrew Gabriel" wrote in message
.. .
In article ,
Geoff Lane writes:
I've recently had an extension built with a new Glow Worm 30ci combi
boiler fitted.

There is a little old pipework remaining and one small rad otherwise
the system is new.

My previous gravity system gave no trouble, apart from the occasional
pump, it worked faultlessly but owing to a need for instant hot water
I went for a combi.

After 16 months the secondary heat exchanger failed, as I had not had
the apparently mandatory service this was not covered by warranty so I
had a very expensive repair.

The service engineer said this was due to the system not being flushed
as the heat exchanger was blocked.

Which side blocked? If you are in a hard water area, you can
expect the secondary side to scale up. I recently descalled
a friend's one in Baxi 105, but that took 4 years to block,
with a family of 5 including two babies.

Sounds like crud in the primary side.

I am now led to believe that system flushing appears to be a necessary
requirement for combis due to the design, how important is this
flushing, I would have thought any modern boiler should have some
filtering system to prevent fouling of the internals.

Desludging is needed in all systems not just combis. Also fit a Magaclean
filter on the CH return, as this will catch debris and iron.

There shouldn't be any new debris appearing in the heating
circuit in the first place (at least not within 16 months).

Depends on how much crud was already in the old system. The Glow Worms are
good boilers, and a failure like this is very rare.

On Sat, 19 Nov 2005 11:54:01 +0000, Ed Sirett
wrote:

I am now led to believe that system flushing appears to be a necessary
requirement for combis due to the design, how important is this
flushing, I would have thought any modern boiler should have some
filtering system to prevent fouling of the internals.


Complete cleaning of the existing pipes and radiators (by flushing or
otherwise) is essential.

I would have to agree that flushing could only benefit but how
essential is it; as previously mentioned my old gravity system worked
for years without any flushing.

The new combi failed within 16 months, I am not an engineer but would
have thought filters should protect vulnerable parts of a boiler.

Geoff Lane

"Geoff Lane" wrote in message
...
On Sat, 19 Nov 2005 11:54:01 +0000, Ed Sirett
wrote:

I am now led to believe that system flushing appears to be a necessary
requirement for combis due to the design, how important is this
flushing, I would have thought any modern boiler should have some
filtering system to prevent fouling of the internals.


Complete cleaning of the existing pipes and radiators (by flushing or
otherwise) is essential.

I would have to agree that flushing could only benefit but how
essential is it; as previously mentioned my old gravity system worked
for years without any flushing.

The new combi failed within 16 months, I am not an engineer but would
have thought filters should protect vulnerable parts of a boiler.

Most makers do not put them on. A few do. Alpha have a cyclone filter.

On Sat, 19 Nov 2005 17:06:17 +0000, Geoff Lane wrote:

On Sat, 19 Nov 2005 11:54:01 +0000, Ed Sirett
wrote:

I am now led to believe that system flushing appears to be a necessary
requirement for combis due to the design, how important is this
flushing, I would have thought any modern boiler should have some
filtering system to prevent fouling of the internals.


Complete cleaning of the existing pipes and radiators (by flushing or
otherwise) is essential.

I would have to agree that flushing could only benefit but how
essential is it; as previously mentioned my old gravity system worked
for years without any flushing.

The new combi failed within 16 months, I am not an engineer but would
have thought filters should protect vulnerable parts of a boiler.

Geoff Lane

The old system was probably full of crud but it didn't have a big effect
on it's operation. There is no problem with combi boilers _if_ the system
is cleaned out properly prior to fitting, other wise there can be trouble
as you have found out.

Thorough flushing now together with cleaning/replacement of the 2ndary
heatX should do the trick.





--
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

"Ed Sirett" wrote in message
news
On Sat, 19 Nov 2005 17:06:17 +0000, Geoff Lane wrote:

On Sat, 19 Nov 2005 11:54:01 +0000, Ed Sirett
wrote:

I am now led to believe that system flushing appears to be a necessary
requirement for combis due to the design, how important is this
flushing, I would have thought any modern boiler should have some
filtering system to prevent fouling of the internals.


Complete cleaning of the existing pipes and radiators (by flushing or
otherwise) is essential.

I would have to agree that flushing could only benefit but how
essential is it; as previously mentioned my old gravity system worked
for years without any flushing.

The new combi failed within 16 months, I am not an engineer but would
have thought filters should protect vulnerable parts of a boiler.

Geoff Lane

The old system was probably full of crud but it didn't have a big effect
on it's operation. There is no problem with combi boilers _if_ the system
is cleaned out properly prior to fitting, other wise there can be trouble
as you have found out.

Thorough flushing now together with cleaning/replacement of the 2ndary
heatX should do the trick.

An fit a filter on the return to the boiler, which should be the case with
any system anyway.

On Sat, 19 Nov 2005 10:22:00 -0000, "Doctor Drivel"
wrote:



Desludging is needed in all systems not just combis. Also fit a Magaclean
filter on the CH return, as this will catch debris and iron.

Are these easy to fit.

Geoff Lane

"Geoff Lane" wrote in message
...
On Sat, 19 Nov 2005 10:22:00 -0000, "Doctor Drivel"
wrote:



Desludging is needed in all systems not just combis. Also fit a
Magaclean
filter on the CH return, as this will catch debris and iron.

Are these easy to fit.

http://tinyurl.com/atx7n
http://www.magnaclean.co.uk