This my third go at getting somewhere with my ailing boiler.
The problem now appears to be that the thermocouple is failing at high
temperatures. So it will stay on all night but it will stop working after
the boiler runs for 10 minuites or so.
Does anyone have any experience of this?
I have put in a new thermocouple but the same thing is happening.

Any thoughts

Stony

This my third go at getting somewhere with my ailing boiler.
The problem now appears to be that the thermocouple is failing at high
temperatures.

If your boiler is old enough to take a thermocouple, you might want to
consider replacing it. A modern boiler would have 90%+ efficiency, instead
of the 50-65% you are likely to be getting now. It may be worth making a
judgement on whether or not a replacement would make financial sense,
particularly if the old boiler is starting to keel over. There's a lot of
gas to be saved.

Christian.

In article ,
"Stoney" writes:
This my third go at getting somewhere with my ailing boiler.
The problem now appears to be that the thermocouple is failing at high
temperatures. So it will stay on all night but it will stop working after
the boiler runs for 10 minuites or so.
Does anyone have any experience of this?
I have put in a new thermocouple but the same thing is happening.

Yes, I've seen the same problem with a gas fire which Eastern Gas fitted.
Problem was too large a pressure drop when the main jets were lit,
which resulted in pilot light shrinking. They had to come back and
take a feed from the gas main, rather than running it from an old
gas lamp pipe.

Have you checked the pilot flame's size/shape against the servicing
manual? It might be that it's misshapen due to partial blockage,
and the change in airflow when the main burner lights is taking it
away from the thermocouple. Another possibility is the thermocouple
isn't mounted at the right place/height. Another thought that occurs
to me is the flue's blocked, causing the flames to drift into the
wrong place due to lack of airflow (and consequent risk of CO release).

--
Andrew Gabriel

"Andrew Gabriel" wrote in message
...
In article ,
"Stoney" writes:
This my third go at getting somewhere with my ailing boiler.
The problem now appears to be that the thermocouple is failing at high
temperatures. So it will stay on all night but it will stop working
after
the boiler runs for 10 minuites or so.
Does anyone have any experience of this?
I have put in a new thermocouple but the same thing is happening.

Yes, I've seen the same problem with a gas fire which Eastern Gas fitted.
Problem was too large a pressure drop when the main jets were lit,
which resulted in pilot light shrinking. They had to come back and
take a feed from the gas main, rather than running it from an old
gas lamp pipe.

Have you checked the pilot flame's size/shape against the servicing
manual? It might be that it's misshapen due to partial blockage,
and the change in airflow when the main burner lights is taking it
away from the thermocouple. Another possibility is the thermocouple
isn't mounted at the right place/height. Another thought that occurs
to me is the flue's blocked, causing the flames to drift into the
wrong place due to lack of airflow (and consequent risk of CO release).

On my old gas boiler, apart from the occasional thermocouple (2 in 20
years), the problem has been minute particles of dirt in the gas supply
slowly blocking up the pilot light.

The symptoms (as suggested above) are a pilot light that is small, and does
not really cover the thermocouple well.

Stays in overnight but doesn't survive after the first long burn.

The cure for me is to remove the pilot jet, and clean it out with fuse wire.

Crude, but effective.

Once you have done it, you can easily see the difference in the flame.

You could even get a spare jet (cheap enough) and fit the new one then clean
the old one as a backup.

HTH
Dave R

P.S. Christian - do they do direct replacements i.e. ground floor boiler in
the centre of the house using chimney flue, or do all modern boilers vent
directly (or nearly directly) to the outside?
There is a vast difference between the strategy for direct replacement and
moving all the pipes to an outside wall.

P.S. Christian - do they do direct replacements i.e. ground floor boiler in
the centre of the house using chimney flue, or do all modern boilers vent
directly (or nearly directly) to the outside?

You probably don't want an old open flue system. You wouldn't get all the
cost saving benefit of modern fan flued (and condensing) designs. However,
most boiler's flue systems could be shoved up a chimney. If it is
particularly long, the Keston Celcius 25 has the cheapest, as it is run with
a couple of plastic drainpipes.

A typical modern boiler can cope with an effective flue length of around 20m
(some are better, some are worse). A bend adds a metre or two to the
effective length. The flues can be run horizontally (with a slight incline
to allow condensate to drain) or vertically.

In some ways, a chimney is the ideal place to run a flue, as the plume
discharge is well away from the windows and no-one minds the steam floating
away from the terminal in quite the same way, as it is evocative of the old
coal burning days.

Christian.

"Christian McArdle" wrote in message
t...
This my third go at getting somewhere with my ailing boiler.
The problem now appears to be that the thermocouple is failing at high
temperatures.

If your boiler is old enough to take a thermocouple, you might want to
consider replacing it. A modern boiler would have 90%+ efficiency, instead
of the 50-65% you are likely to be getting now.

Can you explain how you calculate efficiency - is it for example :
Given the amount of heat ( in say joules ) that is released by the burning a
specific quantity
of gas, find the amount of heat transfered to the water and take the
quotient ?

Steve

Can you explain how you calculate efficiency - is it for example :
Given the amount of heat ( in say joules ) that is released by the burning
a
specific quantity
of gas, find the amount of heat transfered to the water and take the
quotient ?

It is far more complicated than that. In fact, under the calculation method
used, it is even possible to get more than 100% under certain conditions.
However, it does approximate the potential absolute efficiency in
translating fuel energy into useful heat energy that may be distributed
around the system. See www.sedbuk.com for details.

Christian.

"Christian McArdle" wrote in message
t...
Can you explain how you calculate efficiency - is it for example :
Given the amount of heat ( in say joules ) that is released by the
burning
a
specific quantity
of gas, find the amount of heat transfered to the water and take the
quotient ?

It is far more complicated than that. In fact, under the calculation
method
used, it is even possible to get more than 100% under certain conditions.
However, it does approximate the potential absolute efficiency in
translating fuel energy into useful heat energy that may be distributed
around the system. See www.sedbuk.com for details.


So this calculation may give an efficiency of greater than 100% - if so, I
believe this is breaking the
well tested empirical laws of thermodynamics. ( Can any physicists help, my
memory is bad ). The boiler manufacturers should immediately publish this
result :-) I suspect that that, rather than this being the case,
the boiler is nowhere near 100% efficient - the obvious example is the fact
that they all chuck heat out
the flue - even the condensing ones.

What I would be intersted in is :
- A sensible definition of efficiency
- the reason why modern boilers claim such a big efficiency increase over
the older designs - are you comparing older non-condensing boilers with
newer condensing designs.

I couldnt find the calculation details you mention - where is it on the
sedbuk site ?

Steve

I couldnt find the calculation details you mention - where is it on the
sedbuk site ?

There isn't an actual methodology on the site that I've found. However, it
does state that the calculation makes various assumptions and calculations
based on the likely heating profile required in the UK. It isn't a simple
energy out/energy in calculation at all.

Christian.

"Christian McArdle" wrote in message
t...
I couldnt find the calculation details you mention - where is it on the
sedbuk site ?

There isn't an actual methodology on the site that I've found. However, it
does state that the calculation makes various assumptions and calculations
based on the likely heating profile required in the UK. It isn't a simple
energy out/energy in calculation at all.

Christian.

I see - I did find another site that had some more info - still not enough.
However it is does appear ( at first ) a little misleading to see
efficiences of 100% or more percent quoted !

I talked to a guy at work and he says that they basically fiddle the "energy
into the system" value to be
a low value and this is how they achieve such a high efficiency.
He also said that modern boilers used insulation to stop wasting heat by
transfer into the surrounding space
and that they do achieve lower flue temperatures which means they are
extracting more heat from the gas.

Thanks for the info.

Steve

"sro" wrote in message
...

"Christian McArdle" wrote in message
t...
I couldnt find the calculation details you mention - where is it on the
sedbuk site ?

There isn't an actual methodology on the site that I've found. However,
it
does state that the calculation makes various assumptions and
calculations
based on the likely heating profile required in the UK. It isn't a
simple
energy out/energy in calculation at all.

Christian.

I see - I did find another site that had some more info - still not
enough.
However it is does appear ( at first ) a little misleading to see
efficiences of 100% or more percent quoted !

I talked to a guy at work and he says that they basically fiddle the
"energy
into the system" value to be
a low value and this is how they achieve such a high efficiency.
He also said that modern boilers used insulation to stop wasting heat by
transfer into the surrounding space
and that they do achieve lower flue temperatures which means they are
extracting more heat from the gas.

Thanks for the info.

The higher efficiencies are due to better combustion, alloy condensing heat
exchangers, etc. The over 100% is because when they made the scale latent
heat was not taken into account. Condensing boilers make a mockery of this.
Very few boilers have insulation around the heat exchangers.





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He also said that modern boilers used insulation to stop wasting heat by
transfer into the surrounding space and that they do achieve lower flue
temperatures which means they are extracting more heat from the gas.

Indeed, although it is the much larger, more efficient heat exchanger which
does this, rather than insulation.

A well designed condensing boiler installation might have a flue temperature
of 50C, compared to an old boiler with 300C. The flue temperature being
considerably lower than 100C is the cause of all the pluming. Although
people worry about it, thinking it is a health hazard, the emissions in that
plume are much better than those in the invisible 300C one. But you can't
see the 300C version, so no-one cares.

Christian.

"Christian McArdle" wrote in message
t...
He also said that modern boilers used insulation to stop wasting heat by
transfer into the surrounding space and that they do achieve lower flue
temperatures which means they are extracting more heat from the gas.

Indeed, although it is the much larger, more efficient heat exchanger
which
does this, rather than insulation.

A well designed condensing boiler installation might have a flue
temperature
of 50C, compared to an old boiler with 300C. The flue temperature being
considerably lower than 100C is the cause of all the pluming. Although
people worry about it, thinking it is a health hazard, the emissions in
that
plume are much better than those in the invisible 300C one. But you can't
see the 300C version, so no-one cares.


Thanks again - and now the real question, are condensing boilers unreliable
?
Here is an example of what I want from a boiler :

- Run for 18 years with minimal ( 3 or 4 thermocouples ) maintenance ( my
old fashioned boiler )
- I find it amazing that modern combis seem to need new bits after a couple
of years

Am I being unrealistic - are all modern devices complicated and unreliable ?
:-)

Steve

In article ,
"IMM" writes:
Very few boilers have insulation around the heat exchangers.

Keston does. However, that might be more to prevent frying
the electrics inside the boiler casing, as most of the heat
which escapes from the heat exchanger into the boiler case
would simply serve to preheat the combustion air, since the
case is vented only out through the combustion chamber. Thus
the heat would not be lost -- it cleverly goes back into the
combustion chanber. The front of the casing does get a bit
warm just round the heat exchanger, so a little is lost that
way.

One figure Keston don't give is the heat input to the room
from the boiler casing, which would have been useful to know
when I originally did all the heating calculations (some other
manufacturers do). I just ignored it, and that doesn't seem to
have caused any great error in that room, so it's probably not
a lot.

--
Andrew Gabriel

"sro" wrote in message
...

"Christian McArdle" wrote in message
t...
He also said that modern boilers used insulation to stop wasting heat
by
transfer into the surrounding space and that they do achieve lower
flue
temperatures which means they are extracting more heat from the gas.

Indeed, although it is the much larger, more efficient heat exchanger
which
does this, rather than insulation.

A well designed condensing boiler installation might have a flue
temperature
of 50C, compared to an old boiler with 300C. The flue temperature being
considerably lower than 100C is the cause of all the pluming. Although
people worry about it, thinking it is a health hazard, the emissions in
that
plume are much better than those in the invisible 300C one. But you
can't
see the 300C version, so no-one cares.


Thanks again - and now the real question,
are condensing boilers unreliable ?

No. They are same as a system boiler except they have a plastic drain pipe
attached.

Here is an example of what I want from a boiler :

- Run for 18 years with minimal ( 3 or 4 thermocouples )
maintenance ( my old fashioned boiler )

That is possible, but you have to buy a top of the range boiler. As in all
aspects of product prices, more expensive "generally" means better quality.
Not always though.

- I find it amazing that modern combis seem to need new bits after a
couple
of years

Depends on what make and model again. Cheap units break down more. Poorly
installed units break down more too. A combi is just a system boiler with a
water section. No reason for it to be unreliable at all. Some combi's have
all the functions integrated to ensure no operating problems. The
Microgenus is one boiler with all integrated.

Am I being unrealistic

yes.

- are all modern devices complicated and unreliable ?

No. Depends on what you buy.



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"Andrew Gabriel" wrote in message
...
In article ,
"IMM" writes:
Very few boilers have insulation around the heat exchangers.

Keston does.

One of the few and they tend to be the upmarket boilers.

However, that might be more to prevent frying
the electrics inside the boiler casing, as most of the heat
which escapes from the heat exchanger into the boiler case
would simply serve to preheat the combustion air, since the
case is vented only out through the combustion chamber. Thus
the heat would not be lost -- it cleverly goes back into the
combustion chanber. The front of the casing does get a bit
warm just round the heat exchanger, so a little is lost that
way.

One figure Keston don't give is the heat input to the room
from the boiler casing, which would have been useful to know
when I originally did all the heating calculations (some other
manufacturers do). I just ignored it, and that doesn't seem to
have caused any great error in that room, so it's probably not
a lot.

--
Andrew Gabriel


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In article ,
"sro" writes:

Am I being unrealistic - are all modern devices complicated and unreliable ?
:-)

Yes. By turning such products into consumables rather than capital
purchases, the manufacturers keep themselves in business.
OTOH, such products are vastly cheaper in real terms than their
older long-lasting predecessors.

I seriously doubt you'll get 18 years out of any current boiler
without some major parts breaking. I also seriously doubt any
manufacturer will supply spares for anything like 18 years.

Thinking back over many threads in this newsgroup, the combi
part of a combi boiler does seem to be cause for many failures.
If you were looking for something trouble-free, you might want
to avoid a combi.

I have seen fewer problems than I might have expected specific
to condensing boilers reported here, so that might not be
something to worry about so much. However, that could just be
because there are relatively few condensing boilers used by
participents in this newsgroup -- that's hard to tell. The few
problems which have come up here have been initial teething
problems.

--
Andrew Gabriel

"IMM" wrote in message
...

"sro" wrote in message
...

"Christian McArdle" wrote in message
t...
He also said that modern boilers used insulation to stop wasting heat
by
transfer into the surrounding space and that they do achieve lower
flue
temperatures which means they are extracting more heat from the gas.

Indeed, although it is the much larger, more efficient heat exchanger
which
does this, rather than insulation.

A well designed condensing boiler installation might have a flue
temperature
of 50C, compared to an old boiler with 300C. The flue temperature
being
considerably lower than 100C is the cause of all the pluming. Although
people worry about it, thinking it is a health hazard, the emissions
in
that
plume are much better than those in the invisible 300C one. But you
can't
see the 300C version, so no-one cares.


Thanks again - and now the real question,
are condensing boilers unreliable ?

No. They are same as a system boiler except they have a plastic drain
pipe
attached.

Here is an example of what I want from a boiler :

- Run for 18 years with minimal ( 3 or 4 thermocouples )
maintenance ( my old fashioned boiler )

That is possible, but you have to buy a top of the range boiler. As in
all
aspects of product prices, more expensive "generally" means better
quality.
Not always though.

- I find it amazing that modern combis seem to need new bits after a
couple
of years

Depends on what make and model again. Cheap units break down more. Poorly
installed units break down more too. A combi is just a system boiler with
a
water section. No reason for it to be unreliable at all. Some combi's
have
all the functions integrated to ensure no operating problems. The
Microgenus is one boiler with all integrated.

Am I being unrealistic

yes.

- are all modern devices complicated and unreliable ?

No. Depends on what you buy.

A fallacy is that combi's are unreliable. Some are, some are not, there are
the Ladas of the combi world as well as the Mercs. Some conventional
boilers are unreliable. A friends once had a Fuelsaver, much simpler than a
combi, and gave continuous trouble. He eventually replaced it after only 6
years with a "combi".

"All" the system except the rads is in the box. In a cylinder/tank setup, if
the ball-cock has trouble in the cold tank in the loft, no one blames that
on the boiler downstairs.

Compare a boiler/cylinder/cold tank system with a combi, you have to take
all of the servicing of the "system" (and that includes rads) and compare it
with servicing of a combi system (and that includes rads). Assuming the
rads and thermostat valves on each system are of equal quality.

You have to compare like-with-like. Comparing a combi "white box" with a
simple cast-iron boiler "white box" is ridiculous. You have to compare
total system vs total system.

All the old wives tales and fallacies about combis no longer exist. They can
do two bathrooms, they are high quality and reliable, they do have instant
hot water at the taps, they are cheap to install offsetting the high initial
"box" price, they are economical to run.

I had a Potterton Neatheat regular boiler for over 20 years. The boiler was
very reliable in itself because there was not much in it. In that time I
went through:

Outside the boiler:
3 pumps, a zone valve, a zone valve motor, a cylinder, cylinder stat, room
stat and a programmer.

On the boiler:
a relay, flue fan and a pressure differential switch.

Overall the "system" was not that reliable. I am certain a good Vaillant
combi would have given far less trouble over 20 years.



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"Andrew Gabriel" wrote in message
...
In article ,
"sro" writes:

Am I being unrealistic - are all modern devices complicated and
unreliable ?
:-)

Yes. By turning such products into consumables rather than capital
purchases, the manufacturers keep themselves in business.
OTOH, such products are vastly cheaper in real terms than their
older long-lasting predecessors.

I seriously doubt you'll get 18 years out of any current boiler
without some major parts breaking.

As most have pumps inside , pumps don't last that long.



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In article ,
"IMM" writes:

"Andrew Gabriel" wrote in message
...
In article ,
"sro" writes:

Am I being unrealistic - are all modern devices complicated and
unreliable ?
:-)

Yes. By turning such products into consumables rather than capital
purchases, the manufacturers keep themselves in business.
OTOH, such products are vastly cheaper in real terms than their
older long-lasting predecessors.

I seriously doubt you'll get 18 years out of any current boiler
without some major parts breaking.

As most have pumps inside , pumps don't last that long.

If the pump is a generic part, that's not a problem.
If the pump is a special part manufactured for that
boiler, then the boiler is probably dead within some
5 years or so of manufacturer ceasing making it.

--
Andrew Gabriel

In article ,
"IMM" writes:
"sro" wrote in message
...

Thanks again - and now the real question,
are condensing boilers unreliable ?

No. They are same as a system boiler except they have a plastic drain pipe
attached.

Also worth mentioning that they have acid continuously running over
the heat exchanger. Some have stainless steel heat exchangers, whilst
others have aluminium alloy heat exchangers. I would not be surprised
to find a significant difference in the life of these two types.
I suspect that a heat exchanger failing in a condensing boiler more
than perhaps 6 years old is not likely to be regarded as an economic
repair.

--
Andrew Gabriel

"Andrew Gabriel" wrote in message
...
In article ,
"IMM" writes:
"sro" wrote in message
...

Thanks again - and now the real question,
are condensing boilers unreliable ?

No. They are same as a system boiler except they have a plastic drain
pipe
attached.

Also worth mentioning that they have acid continuously running over
the heat exchanger. Some have stainless steel heat exchangers, whilst
others have aluminium alloy heat exchangers. I would not be surprised
to find a significant difference in the life of these two types.

Installed properly they should both last quite a while. There are plenty of
Ideal aluminium heat exchanger condensers about, and have been around for
many years.

I suspect that a heat exchanger failing in
a condensing boiler more than perhaps
6 years old is not likely to be regarded as an economic
repair.

Depends on price or repair and a new item, as always. Some Ideal heat
exchangers are not that big, so can't be that expensive to a new boiler.
Also new condensing boiler prices are dropping, and soon will be the norm,
so prices will drop further.

So you are in the situation of 15 years ago when 99.9% of boilers were
regular boilers. Some where expensive to change the heat exchangers, other,
mainly the finned copper tube one piece exchangers were cheap and super
simple to do. see:
http://tinyurl.com/r1xg
The heat exchanger just slides out.

A spiral tube heat condensing heat exchanger is a matter of screwing off the
pre-mix burner and the flue cxn.






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"Christian McArdle" wrote in message
t...
I couldnt find the calculation details you mention - where is it on the
sedbuk site ?

There isn't an actual methodology on the site that I've found. However, it
does state that the calculation makes various assumptions and calculations
based on the likely heating profile required in the UK. It isn't a simple
energy out/energy in calculation at all.

The SEDBUK method of assessment is to be replaced by an EU method.



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Andrew Gabriel wrote:

In article ,
"sro" writes:

Am I being unrealistic - are all modern devices complicated and unreliable ?
:-)

Yes. By turning such products into consumables rather than capital
purchases, the manufacturers keep themselves in business.
OTOH, such products are vastly cheaper in real terms than their
older long-lasting predecessors.

I seriously doubt you'll get 18 years out of any current boiler
without some major parts breaking. I also seriously doubt any
manufacturer will supply spares for anything like 18 years.

Once a boiler has had a small water leak for a while the corrosion and
associated problems seem to send it on a downward path.

This is a straw poll of the boiler failures for which I have ended up
replacing the boiler (often with a Vaillant Turbomax+ 824e).

1) Saunier Duval combi - poor HW perfomance very noisy. about 10 years
old.
2) Ideal Mexico - floor standing CI - 25 years old?
primary circuit corrosion leading to heat exchanger failure due to
indirect coil leakage.
3) GlowWorm Space saver - 22 years old - refurbishment - needed
[cylinder] cupboard space.
4) Vaillant VCW combi - abused life of 17 years (lack of maintainance,
zero primary pressure etc.) - multiple faults.
5) Vaillant VCW about 12 years old - good order - spaced needed for new
kitchen - new boiler to outside cupboard.
6) Glow Worm back boiler - thermostat failure leading to safety notice
by fire brigade! - say 20 years old.
7) Ideal Concord - working order - say 25-30 years old - inefficiency.
8) Glow Worm back boiler - inefficiency - about 20 years old.
9) Glow Worm Space Saver - primary circuit corrosion (pumping over)
about 15 years old- HE failure.
10) Potterton Profile - serious primary circuit corrosion about 10 years
old - HE failure.
11) Vaillant VCW combi - 17 years old, PCB failure - customer chose
replacement rather than a repair.
12) Ideal Condord - thermostat failure leading - about 25 years.
13) Thorn Apollo - 15 years? - neede cylinder space and HW pressure.
14) Alde thermal storage combi - (7 kW boiler and heat bank in a box) -
poor HW performace and not enough stored energy. - 10 years old.

Looks like a good few of the CI monsters would go on and on until their
thermostats would fail provided their primary circuits did not eat them
first!

In the nominal 20 year life of the boiler it is likely to burn 2-5 times
the cost in gas of its total installed cost

--
Ed Sirett - Property maintainer and registered gas fitter.
The FAQ for uk.diy is at 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
...
Andrew Gabriel wrote:

In article ,
"sro" writes:

Am I being unrealistic - are all modern devices complicated and
unreliable ?
:-)

Yes. By turning such products into consumables rather than capital
purchases, the manufacturers keep themselves in business.
OTOH, such products are vastly cheaper in real terms than their
older long-lasting predecessors.

I seriously doubt you'll get 18 years out of any current boiler
without some major parts breaking. I also seriously doubt any
manufacturer will supply spares for anything like 18 years.

Once a boiler has had a small water leak for a while the corrosion and
associated problems seem to send it on a downward path.

This is a straw poll of the boiler failures for which I have ended up
replacing the boiler (often with a Vaillant Turbomax+ 824e).

1) Saunier Duval combi - poor HW perfomance very noisy. about 10 years
old.
2) Ideal Mexico - floor standing CI - 25 years old?
primary circuit corrosion leading to heat exchanger failure due to
indirect coil leakage.
3) GlowWorm Space saver - 22 years old - refurbishment - needed
[cylinder] cupboard space.
4) Vaillant VCW combi - abused life of 17 years (lack of maintainance,
zero primary pressure etc.) - multiple faults.
5) Vaillant VCW about 12 years old - good order - spaced needed for new
kitchen - new boiler to outside cupboard.
6) Glow Worm back boiler - thermostat failure leading to safety notice
by fire brigade! - say 20 years old.
7) Ideal Concord - working order - say 25-30 years old - inefficiency.
8) Glow Worm back boiler - inefficiency - about 20 years old.
9) Glow Worm Space Saver - primary circuit corrosion (pumping over)
about 15 years old- HE failure.
10) Potterton Profile - serious primary circuit corrosion about 10 years
old - HE failure.
11) Vaillant VCW combi - 17 years old, PCB failure - customer chose
replacement rather than a repair.
12) Ideal Condord - thermostat failure leading - about 25 years.
13) Thorn Apollo - 15 years? - neede cylinder space and HW pressure.
14) Alde thermal storage combi - (7 kW boiler and heat bank in a box) -
poor HW performace and not enough stored energy. - 10 years old.

Looks like a good few of the CI monsters would go on and on until their
thermostats would fail provided their primary circuits did not eat them
first!

In the nominal 20 year life of the boiler it is likely to burn 2-5 times
the cost in gas of its total installed cost

In your list the failed boilers, not those that were not suitable for the
current usage, would have lasted a lot longer if the system was installed
correctly and/or maintenance was carried out at regular intervals. Even so
there were many 20 year olders despite the abuse.

A well designed system with a condensing spiral tubed heat exchanger, top
mounted burner, with the air intake in clear air rather than in a position
to drag in excessive dust, will last a hell of a long time. The condensate
washes down the heat exchanger cleaning it. A modern boiler that analyses
combustion would last even longer as if the boiler was out of tune it would
lock out.







---
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"Stoney" wrote in message
...
This my third go at getting somewhere with my ailing boiler.
The problem now appears to be that the thermocouple is failing at high
temperatures. So it will stay on all night but it will stop working after
the boiler runs for 10 minuites or so.
Does anyone have any experience of this?
I have put in a new thermocouple but the same thing is happening.

It could be that this is what it's meant to do: some open-flued appliances
(generally gas fires, but maybe some boilers?) have a 'vitiation' device -
an arrangement for detecting that oxygen levels in the air being drawn in
for combustion are dangerously low, and shutting down the appliance. If you
fix this 'problem' it could be the last one you'll fix :-|

Is the boiler in an enclosure of some sort, and if so does it have
any/enough ventilation? Are the main burner flames nice and regular shaped
and blue or straggly and yellow? I would not expect vitiation (depletion of
oxygen) to occur in any reasonable-size room within 10 minutes but there are
some unusual combinations of the location of the boiler and its flue
relative to the natural airflow within the house, which can cause combusion
products not to discharge up the flue but to hang around and starve the
boiler (and cause carbon monoxide production!).



--
John Stumbles
-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
-+
The most dangerous component in a car is the nut that holds the steering
wheel

"Andrew Gabriel" wrote in message
...
In article ,
"sro" writes:

Am I being unrealistic - are all modern devices complicated and
unreliable ?
:-)

Yes. By turning such products into consumables rather than capital
purchases, the manufacturers keep themselves in business.
OTOH, such products are vastly cheaper in real terms than their
older long-lasting predecessors.

I seriously doubt you'll get 18 years out of any current boiler
without some major parts breaking. I also seriously doubt any
manufacturer will supply spares for anything like 18 years.

Thinking back over many threads in this newsgroup, the combi
part of a combi boiler does seem to be cause for many failures.
If you were looking for something trouble-free, you might want
to avoid a combi.

I have seen fewer problems than I might have expected specific
to condensing boilers reported here, so that might not be
something to worry about so much. However, that could just be
because there are relatively few condensing boilers used by
participents in this newsgroup -- that's hard to tell. The few
problems which have come up here have been initial teething
problems.


I think you and I agree here, my experience is that old simple boilers cause
me far less trouble.
I have recent experience of repairing a combi :-(

I also suspect that fitters like combis because it makes installing a
heating system easy for them.
The plumber that used to rip my girlfriend off when her combi gave trouble
did admit to
her that "he loved them" - very good for business :-)

Steve

"IMM" wrote in message
...

"Ed Sirett" wrote in message
...
Andrew Gabriel wrote:

In article ,
"sro" writes:

Am I being unrealistic - are all modern devices complicated and
unreliable ?
:-)

Yes. By turning such products into consumables rather than capital
purchases, the manufacturers keep themselves in business.
OTOH, such products are vastly cheaper in real terms than their
older long-lasting predecessors.

I seriously doubt you'll get 18 years out of any current boiler
without some major parts breaking. I also seriously doubt any
manufacturer will supply spares for anything like 18 years.

Once a boiler has had a small water leak for a while the corrosion and
associated problems seem to send it on a downward path.

This is a straw poll of the boiler failures for which I have ended up
replacing the boiler (often with a Vaillant Turbomax+ 824e).

1) Saunier Duval combi - poor HW perfomance very noisy. about 10 years
old.
2) Ideal Mexico - floor standing CI - 25 years old?
primary circuit corrosion leading to heat exchanger failure due to
indirect coil leakage.
3) GlowWorm Space saver - 22 years old - refurbishment - needed
[cylinder] cupboard space.
4) Vaillant VCW combi - abused life of 17 years (lack of maintainance,
zero primary pressure etc.) - multiple faults.
5) Vaillant VCW about 12 years old - good order - spaced needed for new
kitchen - new boiler to outside cupboard.
6) Glow Worm back boiler - thermostat failure leading to safety notice
by fire brigade! - say 20 years old.
7) Ideal Concord - working order - say 25-30 years old - inefficiency.
8) Glow Worm back boiler - inefficiency - about 20 years old.
9) Glow Worm Space Saver - primary circuit corrosion (pumping over)
about 15 years old- HE failure.
10) Potterton Profile - serious primary circuit corrosion about 10 years
old - HE failure.
11) Vaillant VCW combi - 17 years old, PCB failure - customer chose
replacement rather than a repair.
12) Ideal Condord - thermostat failure leading - about 25 years.
13) Thorn Apollo - 15 years? - neede cylinder space and HW pressure.
14) Alde thermal storage combi - (7 kW boiler and heat bank in a box) -
poor HW performace and not enough stored energy. - 10 years old.

Looks like a good few of the CI monsters would go on and on until their
thermostats would fail provided their primary circuits did not eat them
first!

In the nominal 20 year life of the boiler it is likely to burn 2-5 times
the cost in gas of its total installed cost

In your list the failed boilers, not those that were not suitable for the
current usage, would have lasted a lot longer if the system was installed
correctly and/or maintenance was carried out at regular intervals. Even
so
there were many 20 year olders despite the abuse.

A well designed system with a condensing spiral tubed heat exchanger, top
mounted burner, with the air intake in clear air rather than in a position
to drag in excessive dust, will last a hell of a long time. The
condensate
washes down the heat exchanger cleaning it. A modern boiler that analyses
combustion would last even longer as if the boiler was out of tune it
would
lock out.

You mention correct installation and maintenance.
What are the classic installation errors ?
And as to maintenance - I've watched what gas fitters do - you're lucky if
you get
more than a quick clean and a gas analyser shoved in. What is the important
maintenance ?

Incidentally, you talk of reliablility, one of the electronics engineers
here ended up modifying the board
in his boiler because the b*stard blew up every year and cost him over 100
quid to get fixed - cant
recall the make........

Steve

"sro" wrote in message
...

"Andrew Gabriel" wrote in message
...
In article ,
"sro" writes:

Am I being unrealistic - are all modern devices complicated and
unreliable ?
:-)

Yes. By turning such products into consumables rather than capital
purchases, the manufacturers keep themselves in business.
OTOH, such products are vastly cheaper in real terms than their
older long-lasting predecessors.

I seriously doubt you'll get 18 years out of any current boiler
without some major parts breaking. I also seriously doubt any
manufacturer will supply spares for anything like 18 years.

Thinking back over many threads in this newsgroup, the combi
part of a combi boiler does seem to be cause for many failures.
If you were looking for something trouble-free, you might want
to avoid a combi.

I have seen fewer problems than I might have expected specific
to condensing boilers reported here, so that might not be
something to worry about so much. However, that could just be
because there are relatively few condensing boilers used by
participents in this newsgroup -- that's hard to tell. The few
problems which have come up here have been initial teething
problems.


I think you and I agree here, my experience is that old simple boilers
cause
me far less trouble.
I have recent experience of repairing a combi :-(

What went wrong?
See my post on this thread of system v system.

I also suspect that fitters like combis because it makes installing a
heating system easy for them.

There is that., and it is cheaper for the customers too.

The plumber that used to rip my girlfriend off when her combi gave trouble
did admit to
her that "he loved them" - very good for business :-)

Well as about 60-70% of all boilers being fitted are combi's then they are
good for business.


---
--

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"sro" wrote in message
...

"IMM" wrote in message
...

"Ed Sirett" wrote in message
...
Andrew Gabriel wrote:

In article ,
"sro" writes:

Am I being unrealistic - are all modern devices complicated and
unreliable ?
:-)

Yes. By turning such products into consumables rather than capital
purchases, the manufacturers keep themselves in business.
OTOH, such products are vastly cheaper in real terms than their
older long-lasting predecessors.

I seriously doubt you'll get 18 years out of any current boiler
without some major parts breaking. I also seriously doubt any
manufacturer will supply spares for anything like 18 years.

Once a boiler has had a small water leak for a while the corrosion and
associated problems seem to send it on a downward path.

This is a straw poll of the boiler failures for which I have ended up
replacing the boiler (often with a Vaillant Turbomax+ 824e).

1) Saunier Duval combi - poor HW perfomance very noisy. about 10 years
old.
2) Ideal Mexico - floor standing CI - 25 years old?
primary circuit corrosion leading to heat exchanger failure due to
indirect coil leakage.
3) GlowWorm Space saver - 22 years old - refurbishment - needed
[cylinder] cupboard space.
4) Vaillant VCW combi - abused life of 17 years (lack of maintainance,
zero primary pressure etc.) - multiple faults.
5) Vaillant VCW about 12 years old - good order - spaced needed for
new
kitchen - new boiler to outside cupboard.
6) Glow Worm back boiler - thermostat failure leading to safety notice
by fire brigade! - say 20 years old.
7) Ideal Concord - working order - say 25-30 years old - inefficiency.
8) Glow Worm back boiler - inefficiency - about 20 years old.
9) Glow Worm Space Saver - primary circuit corrosion (pumping over)
about 15 years old- HE failure.
10) Potterton Profile - serious primary circuit corrosion about 10
years
old - HE failure.
11) Vaillant VCW combi - 17 years old, PCB failure - customer chose
replacement rather than a repair.
12) Ideal Condord - thermostat failure leading - about 25 years.
13) Thorn Apollo - 15 years? - neede cylinder space and HW pressure.
14) Alde thermal storage combi - (7 kW boiler and heat bank in a
box) -
poor HW performace and not enough stored energy. - 10 years old.

Looks like a good few of the CI monsters would go on and on until
their
thermostats would fail provided their primary circuits did not eat
them
first!

In the nominal 20 year life of the boiler it is likely to burn 2-5
times
the cost in gas of its total installed cost

In your list the failed boilers, not those that were not suitable for
the
current usage, would have lasted a lot longer if the system was
installed
correctly and/or maintenance was carried out at regular intervals. Even
so
there were many 20 year olders despite the abuse.

A well designed system with a condensing spiral tubed heat exchanger,
top
mounted burner, with the air intake in clear air rather than in a
position
to drag in excessive dust, will last a hell of a long time. The
condensate
washes down the heat exchanger cleaning it. A modern boiler that
analyses
combustion would last even longer as if the boiler was out of tune it
would
lock out.

You mention correct installation and maintenance.
What are the classic installation errors ?

Undersized pipes. Filing loop left permanently connected topping up the
system with fresh water constantly. Over-pressurised system. Under
pressurised system. Having rad valves on all rads and no pressure
differential valve fitted, which means no flow through the heat exchanger.
Some boilers now have these as standard inside the white box. Mains water
pressure too high with no pressure reducer fitted. No anti-scale devices
fitted in hard water areas such as phosphor canisters, or electronic
devices. Some boilers have anti-scale incorporated. Because of the poor
installations some makes have incorporated functions to eliminate/reduce
poor fitting and promote longevity. These are the models to DIY.

And as to maintenance - I've watched what gas fitters do - you're lucky if
you get
more than a quick clean and a gas analyser shoved in. What is the
important
maintenance ?

Keeping the system pressure up for one. If it is down, why is it down?
Setting up the gas pressures and the analyser too.

Incidentally, you talk of reliablility, one of the electronics engineers
here ended up modifying the board
in his boiler because the b*stard blew up every year and cost him over 100
quid to get fixed - cant
recall the make........

geoff will tell you about boards on boilers. There are 100s of them. Some
good, some bad.



---
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In article ,
IMM wrote:
I had a Potterton Neatheat regular boiler for over 20 years. The boiler
was very reliable in itself because there was not much in it. In that
time I went through:

Outside the boiler: 3 pumps, a zone valve, a zone valve motor, a
cylinder, cylinder stat, room stat and a programmer.

Wonder why you installed a quality boiler with ****e peripherals?

--
*What was the best thing before sliced bread?

Dave Plowman London SW 12
RIP Acorn

"IMM" wrote in message
...
What went wrong?
See my post on this thread of system v system.

The faults I found and rectified were :

filling loop valve leaking so system allways being topped up
pressure vessel diaphram split
the dump valve jammed open

It was my girlfriends house.
Not sure what caused what because the friendly corgi bloke had been round a
few times to "sort
out problems" - I'd guess that was the boiler switching off due to low
pressure. I reckon he charged the
big callout fee to just re-pressurise and hit the reset button......

It was the first time I had seen a combi - I was lucky that the pressure
vessel change on that model
was easy, apparently some of them make this really awkward.

My house has a very old and simple back boiler and I dread the day I have to
replace it because
everyone I know with a modern system has loads more trouble than I've had in
the last 18 years.
In addition, as with most things, manufacturers try to make money by the
servicing, so devices
are designed to be non-user servicable. Just look at cars - main dealers
charge close on
200 quid for little more than an oil change in the south east......
If I could buy the same old fashioned boiler again I definitely would.

Steve

"sro" wrote in message
...

"IMM" wrote in message
...
What went wrong?
See my post on this thread of system v system.

The faults I found and rectified were :

filling loop valve leaking so system allways being topped up

The filling HAS to be disconnect - not a fault of the system.

pressure vessel diaphram split

Could have been caused by the filling lop always being connected

the dump valve jammed open

Debris. in-line stainers can solve that.

It was my girlfriends house.
Not sure what caused what because the friendly corgi bloke had been round
a
few times to "sort
out problems" - I'd guess that was the boiler switching off due to low
pressure. I reckon he charged the
big callout fee to just re-pressurise and hit the reset button......

It was the first time I had seen a combi - I was lucky that the pressure
vessel change on that model
was easy, apparently some of them make this really awkward.

My house has a very old and simple back boiler and I dread the day I have
to
replace it because
everyone I know with a modern system has loads more trouble than I've had
in
the last 18 years.
In addition, as with most things, manufacturers try to make money by the
servicing, so devices
are designed to be non-user servicable. Just look at cars - main dealers
charge close on
200 quid for little more than an oil change in the south east......
If I could buy the same old fashioned boiler again I definitely would.

Old boiler designs are very inefficient. See the thread on the Potterton
combi too. If you buy a quality product and have it installed correctly
then you will expect 20 years from it.




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Old boiler designs are very inefficient. See the thread on the Potterton
combi too. If you buy a quality product and have it installed correctly
then you will expect 20 years from it.



Yes I know that efficencies have increased although I do take issue with the
way the plumbing/heating
trade love to quote "efficiencies" of more than 100% without explaining the
particular scam they are
using to break the laws of thermodynamics.

I will probably install it myself when the time comes and will follow best
practices along with trade
advice ( luckily I do have access to this ).
As to 20 years - yeah right, just like quality cars dont go wrong if
properly maintained - check out
my pitch for "most boring bmw rants" in the uk.rec.cars.maintenance :-)

I reckon I'll get more trouble, which I'll deal with, but I will be very
interested to check out the claimed
efficiency increases - according to the sedbuk scales a modern boiler should
be double the efficency -
I'll be interested to see how that translates into quantity of gas used.

Steve

In article ,
"sro" writes:

Yes I know that efficencies have increased although I do take issue with the
way the plumbing/heating
trade love to quote "efficiencies" of more than 100% without explaining the
particular scam they are
using to break the laws of thermodynamics.

What would you define as 100% efficient?
Let's suppose you define it as a condensing boiler whose flue
gasses are at the same temperature as its air intake. Now I come
along and invent a scheme for recovery of the latent heat of
fusion from the condensate (i.e. this boiler spits out ice cubes
instead of a dribble of condensate). So my boiler is now 120%
efficient according to your scale, but I didn't break any of
the laws of thermodynamics.

Now just hang on whilst I nip off to the patent office...

--
Andrew Gabriel

"sro" wrote in message
...
Old boiler designs are very inefficient. See the thread on the
Potterton
combi too. If you buy a quality product and have it installed correctly
then you will expect 20 years from it.



Yes I know that efficencies have increased although I do take issue with
the
way the plumbing/heating
trade love to quote "efficiencies" of more than 100% without explaining
the
particular scam they are
using to break the laws of thermodynamics.

I will probably install it myself when the time comes and will follow best
practices along with trade
advice ( luckily I do have access to this ).
As to 20 years - yeah right, just like quality cars dont go wrong if
properly maintained - check out
my pitch for "most boring bmw rants" in the uk.rec.cars.maintenance :-)

The less components the less to go wrong. The Ferroli Modena 102 doesn't
have a 3-way valve and if the pump fails the DHW still works. A decent
boiler.

As for BMWs they breakdown organisations don't rate them either.




---
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In article , Andrew Gabriel
wrote:
Now I come
along and invent a scheme for recovery of the latent heat
of fusion from the condensate (i.e. this boiler spits out
ice cubes instead of a dribble of condensate).

First the good news: Every pub will want one

Now the bad news: If you think pluming is a nuisance just stand
under one of these flue outlets!

--
Tony Bryer SDA UK 'Software to build on' http://www.sda.co.uk
Free SEDBUK boiler database browser
http://www.sda.co.uk/qsedbuk.htm

"Tony Bryer" wrote in message
...
In article , Andrew Gabriel
wrote:
Now I come
along and invent a scheme for recovery of the latent heat
of fusion from the condensate (i.e. this boiler spits out
ice cubes instead of a dribble of condensate).

First the good news: Every pub will want one

I expected pubs to have one already, if they only connected
it to the condesate drain. It's the dry ice maker they want.

"Andrew Gabriel" wrote in message
...
In article ,
"sro" writes:

Yes I know that efficencies have increased although I do take issue with
the
way the plumbing/heating
trade love to quote "efficiencies" of more than 100% without explaining
the
particular scam they are
using to break the laws of thermodynamics.

What would you define as 100% efficient?
Let's suppose you define it as a condensing boiler whose flue
gasses are at the same temperature as its air intake. Now I come
along and invent a scheme for recovery of the latent heat of
fusion from the condensate (i.e. this boiler spits out ice cubes
instead of a dribble of condensate). So my boiler is now 120%
efficient according to your scale, but I didn't break any of
the laws of thermodynamics.

Now just hang on whilst I nip off to the patent office...

Energy in = Energy out I suppose.
Obviously we then argue about what energy in means, but when you know that
some heat goes out the flu
etc etc
then we argue about what consitutes the system - it is not that simple, but
I do feel that the phrase
"efficiency 100%" is very misleading. A bit like lifetime guarantees on
car parts.

I know a bit about how they do their sums and it doesnt include the heat
that you get from condensing
the flue gasses. they basically dont include a large portion of the "energy
in", that way you get
better sounding figures.

Anyhow, isnt there some issue about entropy that means that you can never
get 100% conversion ?

Perhaps I ought to look it up.......

Steve

Andrew Gabriel wrote:

In article ,
"IMM" writes:

"Andrew Gabriel" wrote in message
...
In article ,
"sro" writes:

Am I being unrealistic - are all modern devices complicated and
unreliable ?
:-)

Yes. By turning such products into consumables rather than capital
purchases, the manufacturers keep themselves in business.
OTOH, such products are vastly cheaper in real terms than their
older long-lasting predecessors.

I seriously doubt you'll get 18 years out of any current boiler
without some major parts breaking.

As most have pumps inside , pumps don't last that long.

If the pump is a generic part, that's not a problem.
If the pump is a special part manufactured for that
boiler, then the boiler is probably dead within some
5 years or so of manufacturer ceasing making it.

In many combis the motor and impellor is a standard unit the pump body
is probably bespoke and may incorporate auto air vents etc.

There are spares for combis that are well over 10 years old readily
available.



--
Ed Sirett - Property maintainer and registered gas fitter.
The FAQ for uk.diy is at 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