On Sat, 8 Jan 2005 13:58:12 -0000, "IMM" wrote:


"Andy Hall" wrote in message
.. .
On Sat, 8 Jan 2005 11:08:37 -0000, "IMM" wrote:




The makers stated overload was fine.

Really? In writing?

We had it in writing from the gas boards. Tables etc.

Oh, so it must be right, then. Dear, dear.




No. They could operate at 100% overload, but 100% of the time. Very clear.

I see. So a 100% overload all the time was OK for the domestic
consumer, who the gas boards could push around because they had no
choice......


One would not be fitted to a commercial installation that ran at 100% over
24/7.

Presumably because the customers had deeper pockets and would
complain....


For domestic it was fine. Got it? Read again if you haven't.

Oh definitely. If this is true, it's revealing but not surprising.


A domestic boiler is intermittent in operation, and
modern boilers modulate down, meaning meter
overload is even more feasible these days.

Accompanied by more fudge.

As you are hard of thinking, these days overload would be minimal compared
to 25 years ago.

I don't buy that at all. With the increasing number of combi boilers
installed, the peak demands on gas supplies increases.

But the private sharks will still not accomodate it.

Quite right too.




--

..andy

To email, substitute .nospam with .gl

Andy Hall wrote:

If the manufacturers intended their meters to run as a design goal at
50% over stated capacity, they would rate them that way.
Alternatively, they would manufacture them down to the stated spec.
with much less headroom and more cheaply.

If there is overdesign on the part of the manufacturers it is for
reasons of a safety or accuracy purpose.

This doesn't sound right. In the 1970s the specification was set by the
gas boards engineers. All good engineers overspecify if they want a long
lifetime product. The manufacturers tested the product to a supervised
gas board standard, knowing that if it failed, they would lose the
business. These were the days when products were properly tested for
reliability and products were rated on their lifetime cost as much as on
the ex works price. So IMM is probably right in saying that a gas meter
of his era would perform adequately with a 100% overload. Now that
IEC9000 defines the quality standard, the product is extremely likely to
be crap when it leaves the production line having been built for the
lowest possible cost and may not withstand the 100% overload which IMM
wishes to use. I wouldn't even bet that the modern meter would stay
working correctly when used at 100% load for a couple of years!
Certainly some modern semiconductor electricity meters have a very short
lifespan (12 months AIUI)

Regards
Capitol

Hi IMM,

Hay I didn't mean to offend you.

Yes system boilers are as complex as combis minus the flow restrictor, filter, venturi, diverter system, hot water thermister, flow proving switch and plate heat exchanger/small store where fitted, hydraulic connections and added complexity to the pcb, all of which seldom fo wrong during the period of manufacturer's guarantee, and dmitedly the mid position valve is no saint, but it's quite a simple device against that small list. I prefer S plan myself.

Look, don't get me wrong, I fit combis if that's what people want, I'm not afraid of them, yes they do carry benefits which some people value greater than the shortcomings.

Recently I took my unvented certificate, those guys are fairly certain that the way forward is the system boiler and unvented water storage or thermal store.

I am very fortunate to have a 4 story house so I can manage with open vented hot water and the old 3/4 inch pipes.

My wifes bras actually are what you're most likely to find hung off our Grundfos pump which is probably as old as the Ideal Mexico.

I'm not against modern trends, I fit condensing boilers primarily now, I'd have one at home if my Ideal Mexico became obsolete, which I expect to happen. I now find many regular boilers have a number of obsolete parts.

I love system boilers, saves all that hassle enticing water through the pipes. The added controls of a modern boiler don't scare me, mostly they are reliable and simple to diagnose.

No I recon to be fair, to have a level headed view of all the factors involved in boiler choice, fit combis where appropriate, and when I take out the old cylinder I'm glad for the T money I get for it, and the spead with which I can fit the combi.

Combi swaps are a dream.

Bring em on.

On Sat, 08 Jan 2005 18:34:24 +0000, Capitol
wrote:



Andy Hall wrote:

If the manufacturers intended their meters to run as a design goal at
50% over stated capacity, they would rate them that way.
Alternatively, they would manufacture them down to the stated spec.
with much less headroom and more cheaply.

If there is overdesign on the part of the manufacturers it is for
reasons of a safety or accuracy purpose.

This doesn't sound right. In the 1970s the specification was set by the
gas boards engineers. All good engineers overspecify if they want a long
lifetime product.

If one overspecifies, it is on the basis that the product will be used
within the specification, not at 1.5 or 2x the specification.

The manufacturers tested the product to a supervised
gas board standard, knowing that if it failed, they would lose the
business. These were the days when products were properly tested for
reliability and products were rated on their lifetime cost as much as on
the ex works price. So IMM is probably right in saying that a gas meter
of his era would perform adequately with a 100% overload.

This is a bogus argument. Assuming that the meter manufacturers did
overspecify to apparently improve reliability, and the bodgers abused
it by using it beyond spec. then that reliability margin would be
lost. This then takes the manufacturer back to where he started.

Now that
IEC9000 defines the quality standard, the product is extremely likely to
be crap when it leaves the production line having been built for the
lowest possible cost and may not withstand the 100% overload which IMM
wishes to use.

This is a common misconception. ISO9000 defines quality standards in
the technical and not the colloquial meaning of the word. In other
words, it is documentation of and adherence to a set of processes and
procedures. This bears absolutely no relationship to whether the
resulting product is any good or not. Moreover, processes can be
treated as uncontrolled and then anything can be happening.



I wouldn't even bet that the modern meter would stay
working correctly when used at 100% load for a couple of years!
Certainly some modern semiconductor electricity meters have a very short
lifespan (12 months AIUI)

None of which has anything to do with ISO9000 and specification of
products.



--

..andy

To email, substitute .nospam with .gl

no - system seems stable now - 3 old radiators developed leaks, nowhere
else so far..... touchwood

"Andy Hall" wrote in message
...
On Sat, 08 Jan 2005 18:34:24 +0000, Capitol
wrote:



Andy Hall wrote:

If the manufacturers intended their meters to run as a design goal at
50% over stated capacity, they would rate them that way.
Alternatively, they would manufacture them down to the stated spec.
with much less headroom and more cheaply.

If there is overdesign on the part of the manufacturers it is for
reasons of a safety or accuracy purpose.

This doesn't sound right. In the 1970s the specification was set by the
gas boards engineers. All good engineers overspecify if they want a long
lifetime product.

If one overspecifies, it is on the basis that the product will be used
within the specification, not at 1.5 or 2x the specification.

They gave themselves a hell of a lot of slack. It could do x2 but we never
went to X2. Mdern U6s are built pretty well the same way. There is
overload built in. It just doesn't stop measuring or stop providing gas
when 212 cu ft/hr is exceeded.

"Andy Hall" wrote in message
...
On Sat, 8 Jan 2005 13:58:12 -0000, "IMM" wrote:


"Andy Hall" wrote in message
.. .
On Sat, 8 Jan 2005 11:08:37 -0000, "IMM" wrote:




The makers stated overload was fine.

Really? In writing?

We had it in writing from the gas boards. Tables etc.

Oh, so it must be right, then. Dear, dear.




No. They could operate at 100% overload, but 100% of the time. Very
clear.

I see. So a 100% overload all the time was OK for the domestic
consumer, who the gas boards could push around because they had no
choice......


One would not be fitted to a commercial installation that ran at 100%
over
24/7.

Presumably because the customers had deeper pockets and would
complain....


For domestic it was fine. Got it? Read again if you haven't.

Oh definitely. If this is true, it's revealing but not surprising.


A domestic boiler is intermittent in operation, and
modern boilers modulate down, meaning meter
overload is even more feasible these days.

Accompanied by more fudge.

As you are hard of thinking, these days overload would be minimal
compared
to 25 years ago.

I don't buy that at all. With the increasing number of combi boilers
installed, the peak demands on gas supplies increases.

But the private sharks will still not accomodate it.

Quite right too.

Only on uk.d-i-y. ............and your knowledge of gas metering is????
er, er, er, what you picked up here, by read what I wrote. duh!

On Sat, 8 Jan 2005 21:52:52 -0000, "IMM" wrote:


They gave themselves a hell of a lot of slack. It could do x2 but we never
went to X2. Mdern U6s are built pretty well the same way. There is
overload built in. It just doesn't stop measuring or stop providing gas
when 212 cu ft/hr is exceeded.


Obviously not, but this does not mean that it is good practice to
deliberately operate equipment outside the manufacturer's
specifications.

Once you go beyond the spec. who defines what the margin is? Did you
get written approval from the meter suppliers that exceeding their
spec. by 1.5 to 2x was OK? Did they honour the warranty?

Are you sure you weren't fired?




--

..andy

To email, substitute .nospam with .gl

"Andy Hall" wrote in message
...
On Sat, 8 Jan 2005 21:52:52 -0000, "IMM" wrote:


They gave themselves a hell of a lot of slack. It could do x2 but we
never
went to X2. Mdern U6s are built pretty well the same way. There is
overload built in. It just doesn't stop measuring or stop providing gas
when 212 cu ft/hr is exceeded.

Obviously not, but this does not
mean that it is good practice to
deliberately operate equipment
outside the manufacturer's
specifications.

It was within spec. Apparently not now the private sharks are on the money
hunt.

On Sun, 9 Jan 2005 01:06:46 -0000, "IMM" wrote:


"Andy Hall" wrote in message
.. .
On Sat, 8 Jan 2005 21:52:52 -0000, "IMM" wrote:


They gave themselves a hell of a lot of slack. It could do x2 but we
never
went to X2. Mdern U6s are built pretty well the same way. There is
overload built in. It just doesn't stop measuring or stop providing gas
when 212 cu ft/hr is exceeded.

Obviously not, but this does not
mean that it is good practice to
deliberately operate equipment
outside the manufacturer's
specifications.

It was within spec.

Which spec.? Yours? The gas board's? The manufacturer's? Was it
written down that this was an officially OK policy?

Apparently not now the private sharks are on the money
hunt.

Apparently not. Good thing really.



--

..andy

To email, substitute .nospam with .gl

"Paul Barker" wrote in message
...

Yes system boilers are as complex
as combis minus the flow restrictor,
filter, venturi, diverter system, hot water
thermister, flow proving
switch and plate heat exchanger/small
store where fitted, hydraulic
connections and added complexity
to the pcb,

Some combi's are very simple with no diverter valves. The W-B Junior and
Ferroli Modena come to mind.

Extra complexity on the pcs is invisible to maintenance men. Ask Maxie, he
recons them.

Look, don't get me wrong, I fit
combis if that's what people want, I'm
not afraid of them, yes they do carry
benefits which some people value
greater than the shortcomings.

That is a change of stance.

Recently I took my unvented certificate,
those guys are fairly certain
that the way forward is the system
boiler and unvented water storage or
thermal store.

They would wouldn't they. 60-70% of all boilers old in the UK are combi's.
The flowrate of them is improving by the month. For a one bath, one or two
showers, the likes of the Alpha CB50 is brilliant, as one poster confirms.
It will even do two baths as long as they are not filled at the same time
(the recovery rate of the store is minutes). No tanks, or fitting
complexity, power showers and a cupboard liberated in v small British homes.
For DIY they are brilliant. Little thinking on the part of the installer.
Most DIY jobs I have seen when they tackle cylinders and tanks is cringeful.

Over one bathroom and a shower or two, I would go heat bank./thermal store
as the benefits outweight unvented.

BTW, I have a Microgenus in a flat, excellent little combi, and Ariston now
give 5 year gurantees on their boilers, and in my house an Ideal condenser
off a weather compensator and a Gledhill Systemate thermal store (a class
act all in one casing). See below on my response to a plumber on here

My wifes bras actually are what
you're most likely to find hung off our
Grundfos pump which is probably
as old as the Ideal Mexico.

Mexico? Get it changed ASAP. You will apprecaite the lower bills.

I'm not against modern trends, I fit
condensing boilers primarily now,

You will have little choice in a few months.

I'd have one at home if my Ideal
Mexico became obsolete,

It is. It came out in 1970, named after the 1970 world cup.

No I recon to be fair, to have a level headed view of all the factors
involved in boiler choice, fit combis where appropriate, and when I
take out the old cylinder I'm glad for the T money I get for it, and
the spead with which I can fit the combi.

Combi swaps are a dream.

Bring em on.

Unless the old boiler had a large balanced flue and you are left with a big
hole. Sometimes it takes longer chiselling the old boiler out than fitting
the new one.

%%%%%%%%%%%%%%%%%

At the risk of being associated with 'dumb
plumbers' I'll give my reasons for recommending
an unvented cylinder rather than a thermal
store. I've got nothing against the technology
of a thermal store but personally feel its had
its day now that condensing boilers will soon
be mandatory to the mass market.

Confusing passage but let's see....

I agree that an unvented cylinder must
be installed by a trained person. IMM
says that UV cyls can explode and while
true it is rare due to the safety features that
are mandatory. UK regulations are lot
stricter than many countries were UV cyls
have been the norm for many
years.

The point is that they can explode, and do. If one explodes an insurance
company will not pay out if the unvented cylinder was not serviced.

To the points in question;
1. Reinstating the air bubble in a megaflow
is not a difficult task.

It is for a pensioner. Many local authorities have removed unvented
cylinders as they had too much hassle of drips from vent pipes because the
air bubbles were never re-instated by the residents, or the pressure vessels
failed. They had an army of men attending these problems.

2. 1" copper overflows are not required
unless the route to discharge is extraordinarly
long. The tundish has a 22mm output and this is
sufficient for most installations. However, the
discharge pipework must not be plastic.

The large metal pipe extracts heat from a house 24/7. For this reason eco
houses don't us them. DPS do a heat banmk that doesn't require an overflow,
so no penetration of the external building fabric.

3. KISS. Which is easier to understand;
the UV cyl or a heatbank?

Both. If dumb plumbers can't understand a thermal store or heat bank they
should work on the milk.

4. Solar. As far as I know OSO and Viessmann
are the only UV cyls to have dual coil models.
Yes, the solar won't heat your radiators, but
since solar systems are designed to work at
their peak in summer, surely this a moot point?

It is not. Solar panels work in winter with clear strong sun. A solar coil
in an integrated thermal store supplying DHW & CH will have solar generated
heat used for CH and DHW. A solar coil in an unvented cylinder is only
available for DHW.

5. condensing boilers. I commented this
elsewhere in the NG. UV cyls are a better
option with a condensing boiler.

Clearly untrue. A heat bank with DHW and heating sections, with the heating
section controller from an outside weather compensator will perform very
efficiently with condensing boiler

With inefficient boilers there is no such choice
between an uv cyl and heatbank.

????

6. DIY. Yes I'll agree that a heatbank
can be DIY-ed. This suggests
the owner has some interest in the
heatbank technology, which is fair
enough.

Or wants high flow DHW cheaply as he can do it himself. It is not a matter
if he has fad for thermal store technology. A DIYer can't fit an unvented
cylinder.

Future owners may not be so inclined.

Future owners will not know the difference. All they know is that a heat
bank will give them high pressure DHW. Also a heat bank can go up to 10
bar, whereas I know of no unvented cylinder that is above 3.5 bar (they are
pressure (reduced).

Still, future employment
for 'plumbers' when the next owners
rip it out to put a megaflow in?

Ignorance from dumb plumbers. I know of one housing estate that were fitting
with Flowmaxes about 12 years ago . Some of the Flowmaxes developed simple
faults, such as flow blending valves failing and the likes. The naive
owners contacted the local dumb lumbers and said it is best to rip them out
and fit a tank in the loft. There are a number of tank now in lofts, when a
£30 part would have solved the problem.

I can give you examples of dumb plumbers putting in a rad system when a
perfectly adequate forced air system is there. All was required was the unit
repairing.

Most plumber are only good for drains and gutters and replacing bathroom
suites.

7. The marque. A 'Megaflow' has become
something of a must-have.
Probably due to marketing and keeping
up with the Jones.

Marketing has promoted an inferior technology that is clear. Also developers
fitting them besuse they easy is also promoted them. Heat banks are just as
easy. Obviously a cheap was done somwhere. "Megaflows a must have"? Please
get real.

Still, the educated customer wins out.
It may be a plus-point on a future house sale.

A megalflow or thermal store? When a customer sees high pressure mains hot
water he is impressed whether Megaflow or heat bank. Heat bank give higher
pressures, up to 10 bar.

8. Boiler cycling. Any system is susceptable
to this if badly installed. I've not seen a modern
UV cylinder which causes the boiler
to cycle before it reaches the desired temperature.

I have.

I only install the keston celsius 25, which has
some features to avoid cycling.

So you blinded by a boiler with load compensating control; the "only" type
you fit.

9. All in one packages. Not something I go
for myself but just a personal choice.

And no reason given. Not impressed.

There are equally valid pros/cons
for this type of unit.

You should be more objective when assessing these matters. You have
everything to gain.

Something tells me you want unvented cylinders to be the norm as only BBA
registered people can fit them. They are NOT cheap and BBA fitting not cheap
either. Your mind is poisoned by vested interest.

"Andy Hall" wrote in message
...
On Sun, 9 Jan 2005 01:06:46 -0000, "IMM" wrote:


"Andy Hall" wrote in message
.. .
On Sat, 8 Jan 2005 21:52:52 -0000, "IMM" wrote:


They gave themselves a hell of a lot of slack. It could do x2 but we
never
went to X2. Mdern U6s are built pretty well the same way. There is
overload built in. It just doesn't stop measuring or stop providing
gas
when 212 cu ft/hr is exceeded.

Obviously not, but this does not
mean that it is good practice to
deliberately operate equipment
outside the manufacturer's
specifications.

It was within spec.

Which spec.? Yours? The gas board's? The manufacturer's? As the gas
were about the only people who boards meters they dictated.

Was it written down that this was an officially OK policy?

Yep.

Apparently not now the
private sharks are on the money
hunt.

Apparently not. Good thing really.

You are naive.

On Sun, 9 Jan 2005 01:51:38 -0000, "IMM" wrote:


"Andy Hall" wrote in message


Which spec.? Yours? The gas board's? The manufacturer's? As the gas
were about the only people who boards meters they dictated.


Did they do bed and breakfast as well? :-)


Was it written down that this was an officially OK policy?

Yep.


I find it very hard to believe that....

Did the manufacturers know? Did the customers?




--

..andy

To email, substitute .nospam with .gl

"Andy Hall" wrote in message
...

Did the manufacturers know?

Yep.

Did the customers?

As they never paid for meters, they didn't need to. Only large commercial
customers paid for metering, but the gas rates they got were very
appealling.

"Markus Splenius" wrote in message
...
On Fri, 07 Jan 2005 01:09:32 +0000, John Rumm
wrote:

Markus Splenius wrote:

What's the most powerful combi you can get? I haven't seen much above
35kw.

40kW units are available from a number of makers. Some like Man do 76kW
one IIRC (you will need a pretty serious gas supply for that ;-)

What are the limitations of a "standard" gas supply? I have a 3
bedroom detached house.


This always starts up a long running thread between dimm and t'others. In
fact there is a recent thread which may still be tailing off.
A domestic standard supply, governor and meter is rated at 6 cubic metres
per hour but dim tells us he has used them on fantastic overloads without
ill effect. If you follow the standards and current legal requirements you
should limit your total house load to 6m^3. This includes any fires,
cookers, boilers etc.
If you need more you should ask your supplier for a greater capacity supply
and meter.

"Andy Hall" wrote in message
...
On Fri, 7 Jan 2005 19:51:13 +0000, Paul Barker
wrote:


I make a good living repairing combis. I have an open vented hot water
cylinder at home and a regular boiler. You couldn't get me to put a
combi in to replace that if you gave it me. I would actually think you
were mad. If you offered as a means of filling a bath quickly another
combi I would call for the men in white coats.

Thank goodness combis are so popular, I'm guaranteed work for many
years to come.

Thank goodness I have enough intelligence to learn from other peoples
mistakes and kept my airing cupboard.

You should ask IMM for his mug (sorry customer) list. These people
have two combis so you could clean up.




Nah - theres too much time (unpaid) waiting for Transco to turn up when you
ring to advise of low pressure from the meter/governor because of the
excessive load.

"John" wrote in message
...

This one is that bright. Sad but true.

On Wed, 12 Jan 2005 17:30:47 +0000 (UTC), "John"
wrote:


"Andy Hall" wrote in message
.. .
On Fri, 7 Jan 2005 19:51:13 +0000, Paul Barker
wrote:


I make a good living repairing combis. I have an open vented hot water
cylinder at home and a regular boiler. You couldn't get me to put a
combi in to replace that if you gave it me. I would actually think you
were mad. If you offered as a means of filling a bath quickly another
combi I would call for the men in white coats.

Thank goodness combis are so popular, I'm guaranteed work for many
years to come.

Thank goodness I have enough intelligence to learn from other peoples
mistakes and kept my airing cupboard.

You should ask IMM for his mug (sorry customer) list. These people
have two combis so you could clean up.




Nah - theres too much time (unpaid) waiting for Transco to turn up when you
ring to advise of low pressure from the meter/governor because of the
excessive load.



Shouldn't matter. You can overload the supply by at least
50%......:-)



--

..andy

To email, substitute .nospam with .gl

"Andy Hall" wrote in message
...

Nah - theres too much time (unpaid) waiting for Transco to turn up when
you ring to advise of low pressure from the meter/governor because of the
excessive load.

Shouldn't matter. You can overload the supply by at least
50%......:-)

Yep. That's true.