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Default Replacing copper HW tank.

Now that the weather is warming up, I'm considering replacing our HW
storage tank (it's about 30 years old, and is getting a bit crusty
around some of the pipe connectors). Before I do, I suppose I ought to
ask if (in everyone's opinion) I should just replace it like-for-like?
Or is there some other direction I ought to be heading in, like
mains-pressure hot water, or just using instant hot-water taps
everywhere instead? Or something else?
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Default Replacing copper HW tank.

Chris Hogg wrote:
On Mon, 12 Mar 2018 10:54:05 +0000, "Dan S. MacAbre"
wrote:

Now that the weather is warming up, I'm considering replacing our HW
storage tank (it's about 30 years old, and is getting a bit crusty
around some of the pipe connectors). Before I do, I suppose I ought to
ask if (in everyone's opinion) I should just replace it like-for-like?
Or is there some other direction I ought to be heading in, like
mains-pressure hot water, or just using instant hot-water taps
everywhere instead? Or something else?


We've just had a traditional sixty-year-old DHW system replaced by an
unvented, mains-pressure system in my late mother's bungalow, which we
intend to move into soon. Several comments:

It's based on a Joule tank, http://bit.ly/2Ht27Gz . The plumbing seems
a lot more complicated than before, with pressure regulators,
expansion vessels, pressure relief valves, tundishes etc all over the
place. The airing cupboard is now a cat's cradle of pipework. Whether
it could be simpler, I don't know. I think it all has to be installed
by a specialist, rather than DIY, BIMBW.

The DHW cylinder itself is much bigger that I expected; this may just
be what the plumber chose to install, rather than being necessary. My
comment to the plumber was that it looked like a section from a Saturn
5 rocket.

A potential disadvantage is that in very cold weather, such as we've
just had and where the mains supply may be off for several days, is
that you have no water at all. At least in our present place when the
water was cut off for 36 hours, we could draw down the water from the
tank in the loft, boiled where appropriate, but that wouldn't be an
option with an unvented system unless some way was found of retaining
the tank, in which case why bother with an unvented system at all.


Well, it's not like we have any problems with what there is now. We
occasionally need to switch on an immersion heater (our little boy has
several baths a day - he likes to play with his toy ships), and the
upstairs hot water pressure is a bit low (but I put a pump in, so it's
okay). It's just that sometimes, thinking of selling the house in the
future, everything might be a bit 'old-fashioned'. The thought of
mains-pressure HW does seem a little scary. And I don't really like
over-complicated things (which is why we still have the 30 year old boiler).
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Default Replacing copper HW tank.

On Mon, 12 Mar 2018 10:54:05 +0000, Dan S. MacAbre wrote:

Now that the weather is warming up, I'm considering replacing our HW
storage tank (it's about 30 years old, and is getting a bit crusty
around some of the pipe connectors). Before I do, I suppose I ought to
ask if (in everyone's opinion) I should just replace it like-for-like?
Or is there some other direction I ought to be heading in, like
mains-pressure hot water, or just using instant hot-water taps
everywhere instead? Or something else?


Does it do what you want?

AFAIK the main reason to have a tank/heat store is if your demand for hot
water is greater than easily supplied by the mains flow. Often a
compromise with a combi boiler.

How old is your boiler? People normally consider changes like this when
changing the boiler. If the rest of the system is working well then just
fitting a new (possibly slightly larger?) cylinder may be the easiest
option.

Other reasons are to free off space used by the cold water storage and
remove worries about freezing pipes in the winter.

I still can't decide if I did the right thing in switching to a combi.

A previous house with a big hot water tank and a shower pump served two
showers simultaneously with lashings of hot water.

The current house has a combi sized to supply two showers simultaneously
but doesn't in any way match the flow rate.

So worth checking the maximum flow rate of the cold mains before you move
away from a cold water storage tank. Noting also that if your mains water
is cut off then a storage tank in the loft can be an unexpected bonus.

Hard or soft water area?

If you are in a hard water area with unsoftened water then your tank may
have more crust on the inside than the outside.

Cheers


Dave R


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Default Replacing copper HW tank.

David wrote:
On Mon, 12 Mar 2018 10:54:05 +0000, Dan S. MacAbre wrote:

Now that the weather is warming up, I'm considering replacing our HW
storage tank (it's about 30 years old, and is getting a bit crusty
around some of the pipe connectors). Before I do, I suppose I ought to
ask if (in everyone's opinion) I should just replace it like-for-like?
Or is there some other direction I ought to be heading in, like
mains-pressure hot water, or just using instant hot-water taps
everywhere instead? Or something else?


Does it do what you want?


It does. I just wonder if I should be 'keeping up with the times',
that's all.

AFAIK the main reason to have a tank/heat store is if your demand for hot
water is greater than easily supplied by the mains flow. Often a
compromise with a combi boiler.

How old is your boiler? People normally consider changes like this when
changing the boiler. If the rest of the system is working well then just
fitting a new (possibly slightly larger?) cylinder may be the easiest
option.

Other reasons are to free off space used by the cold water storage and
remove worries about freezing pipes in the winter.

I still can't decide if I did the right thing in switching to a combi.


The boiler is a 30 year old Thorn Apollo. As long as I replace the
thermocouple and top socket every five or so years, it just keeps going.
I don't want to replace it with something less reliable that I can't
easily fix myself.

A previous house with a big hot water tank and a shower pump served two
showers simultaneously with lashings of hot water.

The current house has a combi sized to supply two showers simultaneously
but doesn't in any way match the flow rate.

So worth checking the maximum flow rate of the cold mains before you move
away from a cold water storage tank. Noting also that if your mains water
is cut off then a storage tank in the loft can be an unexpected bonus.

Hard or soft water area?


Soft.

If you are in a hard water area with unsoftened water then your tank may
have more crust on the inside than the outside.

Cheers


Dave R



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Default Replacing copper HW tank.

On 12/03/2018 10:54, Dan S. MacAbre wrote:
Now that the weather is warming up, I'm considering replacing our HW
storage tank (it's about 30 years old, and is getting a bit crusty
around some of the pipe connectors).Â* Before I do, I suppose I ought to
ask if (in everyone's opinion) I should just replace it like-for-like?
Or is there some other direction I ought to be heading in, like
mains-pressure hot water, or just using instant hot-water taps
everywhere instead?Â* Or something else?


We've had a pressurised hot water system for a few years now. As has
been said, it's relatively complex. The tank is well insulated and
doesn't take much for the boiler to keep the temperature up when the
water's not being used. Generally, we're very pleased with it - in our
case it's all in the cellar (the 'plant room' as the installer called it
because it sounds better than 'coal hole') and doesn't take up any
otherwise useful room.

The downside is that you can only get out the flow that you can put in.
In our case, that means that you can't have two showers at once, or have
a shower while the bath is running. If that's an issue for you, don't
do it.

Cheers
--
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Default Replacing copper HW tank.

On 12/03/2018 10:54, Dan S. MacAbre wrote:

Now that the weather is warming up, I'm considering replacing our HW
storage tank (it's about 30 years old, and is getting a bit crusty
around some of the pipe connectors). Before I do, I suppose I ought to
ask if (in everyone's opinion) I should just replace it like-for-like?
Or is there some other direction I ought to be heading in, like
mains-pressure hot water, or just using instant hot-water taps
everywhere instead? Or something else?


If you are keeping the current boiler, then your options basically come
down to either stored hot water, or some kind of thermal store / heat
bank arrangement.

The setup you have now is simple enough and can work well - however it
has pros and cons and does not suit all properties or usage patterns.

An unvented cylinder will adds a bit of complexity close to the cylinder
- but does away with the need for a cistern in the loft. It has the
advantage of delivering mains pressure (or close to it water to all the
hot taps - so good for showers without the need for pumps etc). You can
still have an immersion backup. To work well though you would need to
make sure you have a decent flow rate from your mains cold supply.

Have a look at the lists of pros/cons etc he

http://wiki.diyfaq.org.uk/index.php/Unvented_DHW

The thermal store options are similar - basically a big tank of hot
water - however its used indirectly to heat the incoming cold water on
demand. A slightly different set of pro's an cons, but handy for example
if you want to incorporate several heat sources like solid fuel and
solar as well as a boiler / immersion.

http://wiki.diyfaq.org.uk/index.php/...and_Heat_Banks

You can buy them ready to go or cobble one together from parts:

http://wiki.diyfaq.org.uk/index.php/DIY_Heat_Bank





--
Cheers,

John.

/================================================== ===============\
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|-----------------------------------------------------------------|
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Default Replacing copper HW tank.

On 12/03/2018 11:25, Chris Hogg wrote:

We've just had a traditional sixty-year-old DHW system replaced by an
unvented, mains-pressure system in my late mother's bungalow, which we
intend to move into soon. Several comments:

It's based on a Joule tank, http://bit.ly/2Ht27Gz . The plumbing seems
a lot more complicated than before, with pressure regulators,
expansion vessels, pressure relief valves, tundishes etc all over the
place. The airing cupboard is now a cat's cradle of pipework. Whether
it could be simpler, I don't know.


Here is the basic layout you can expect:

http://wiki.diyfaq.org.uk/index.php/...ted_cylinde r

I think it all has to be installed
by a specialist, rather than DIY, BIMBW.


Historically it was the case that only unvented cylinders were covered
by building regs (Part 3 document G). These days *all* cylinders are
covered by the building regs. See approved document G for more info.

They also need to be installed by someone who knows what they are doing!
(although that applies to any cylinder - unvented ones may be less well
understood by some plumbers).

Modern installs should also include things like mixing valves to limit
the maximum temperature at the point of use, but again that applies to
all stored water systems.

The DHW cylinder itself is much bigger that I expected; this may just
be what the plumber chose to install, rather than being necessary. My
comment to the plumber was that it looked like a section from a Saturn
5 rocket.


Yup unvented cylinders are often available in larger capacities than
traditional ones. (although you can still do the same trick doubling up
smaller cylinders like you can with a vented system to get more capacity)

Personally I fitted a 210L one which is probably about 5' tall. The
outer shell and integral insulation can make them look a bit more
"solid" than a normal tank. If I were doing it again, I might go for the
next size up.

A potential disadvantage is that in very cold weather, such as we've
just had and where the mains supply may be off for several days, is
that you have no water at all. At least in our present place when the
water was cut off for 36 hours, we could draw down the water from the
tank in the loft, boiled where appropriate, but that wouldn't be an
option with an unvented system unless some way was found of retaining
the tank, in which case why bother with an unvented system at all.


Sometimes upgrading the connection to the mains is way of solving a
number of related problems (lack of flow rate, freezing etc). A nice
32mm MDPE pipe buried deep enough ought not freeze and will make any
mains pressure water system work much better usually.


--
Cheers,

John.

/================================================== ===============\
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|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/
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Default Replacing copper HW tank.

John Rumm wrote:

On 12/03/2018 11:25, Chris Hogg wrote:

We've just had a traditional sixty-year-old DHW system replaced by an
unvented, mains-pressure system in my late mother's bungalow, which we
intend to move into soon. Several comments:

It's based on a Joule tank, http://bit.ly/2Ht27Gz . The plumbing seems
a lot more complicated than before, with pressure regulators,
expansion vessels, pressure relief valves, tundishes etc all over the
place. The airing cupboard is now a cat's cradle of pipework. Whether
it could be simpler, I don't know.


Here is the basic layout you can expect:

http://wiki.diyfaq.org.uk/index.php/...nts_of_an_unve
nted_cylinder

I think it all has to be installed
by a specialist, rather than DIY, BIMBW.


Historically it was the case that only unvented cylinders were covered
by building regs (Part 3 document G). These days *all* cylinders are
covered by the building regs. See approved document G for more info.

They also need to be installed by someone who knows what they are doing!
(although that applies to any cylinder - unvented ones may be less well
understood by some plumbers).

Modern installs should also include things like mixing valves to limit
the maximum temperature at the point of use, but again that applies to
all stored water systems.

The DHW cylinder itself is much bigger that I expected; this may just
be what the plumber chose to install, rather than being necessary. My
comment to the plumber was that it looked like a section from a Saturn
5 rocket.


Yup unvented cylinders are often available in larger capacities than
traditional ones. (although you can still do the same trick doubling up
smaller cylinders like you can with a vented system to get more capacity)

Personally I fitted a 210L one which is probably about 5' tall. The
outer shell and integral insulation can make them look a bit more
"solid" than a normal tank. If I were doing it again, I might go for the
next size up.

A potential disadvantage is that in very cold weather, such as we've
just had and where the mains supply may be off for several days, is
that you have no water at all. At least in our present place when the
water was cut off for 36 hours, we could draw down the water from the
tank in the loft, boiled where appropriate, but that wouldn't be an
option with an unvented system unless some way was found of retaining
the tank, in which case why bother with an unvented system at all.


Sometimes upgrading the connection to the mains is way of solving a
number of related problems (lack of flow rate, freezing etc). A nice
32mm MDPE pipe buried deep enough ought not freeze and will make any
mains pressure water system work much better usually.


As a matter of interest, do you think that is likely to be worth doing
if the water board side connection is 2m of 25mm?

--

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Default Replacing copper HW tank.

On 12/03/2018 12:46, Roger Hayter wrote:
John Rumm wrote:

On 12/03/2018 11:25, Chris Hogg wrote:

We've just had a traditional sixty-year-old DHW system replaced by an
unvented, mains-pressure system in my late mother's bungalow, which we
intend to move into soon. Several comments:

It's based on a Joule tank, http://bit.ly/2Ht27Gz . The plumbing seems
a lot more complicated than before, with pressure regulators,
expansion vessels, pressure relief valves, tundishes etc all over the
place. The airing cupboard is now a cat's cradle of pipework. Whether
it could be simpler, I don't know.


Here is the basic layout you can expect:

http://wiki.diyfaq.org.uk/index.php/...nts_of_an_unve
nted_cylinder

I think it all has to be installed
by a specialist, rather than DIY, BIMBW.


Historically it was the case that only unvented cylinders were covered
by building regs (Part 3 document G). These days *all* cylinders are
covered by the building regs. See approved document G for more info.

They also need to be installed by someone who knows what they are doing!
(although that applies to any cylinder - unvented ones may be less well
understood by some plumbers).

Modern installs should also include things like mixing valves to limit
the maximum temperature at the point of use, but again that applies to
all stored water systems.

The DHW cylinder itself is much bigger that I expected; this may just
be what the plumber chose to install, rather than being necessary. My
comment to the plumber was that it looked like a section from a Saturn
5 rocket.


Yup unvented cylinders are often available in larger capacities than
traditional ones. (although you can still do the same trick doubling up
smaller cylinders like you can with a vented system to get more capacity)

Personally I fitted a 210L one which is probably about 5' tall. The
outer shell and integral insulation can make them look a bit more
"solid" than a normal tank. If I were doing it again, I might go for the
next size up.

A potential disadvantage is that in very cold weather, such as we've
just had and where the mains supply may be off for several days, is
that you have no water at all. At least in our present place when the
water was cut off for 36 hours, we could draw down the water from the
tank in the loft, boiled where appropriate, but that wouldn't be an
option with an unvented system unless some way was found of retaining
the tank, in which case why bother with an unvented system at all.


Sometimes upgrading the connection to the mains is way of solving a
number of related problems (lack of flow rate, freezing etc). A nice
32mm MDPE pipe buried deep enough ought not freeze and will make any
mains pressure water system work much better usually.


As a matter of interest, do you think that is likely to be worth doing
if the water board side connection is 2m of 25mm?


You mean using a larger pipe than theirs? It depends on the
circumstances... If you have say 40m of 1/2" pipe after that, Then any
increase will make a significant difference. The cost of the pipe is
usually only a small part of the overall cost of swapping it, so you may
as well over rather than under spec it.

(Flow resistance is a function of both diameter and length so a short
run of something narrower is not necessarily a show stopper)




--
Cheers,

John.

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

I have no gass so am all electric and so my airing cupboard has just got the
traditional cylinder and immersion heater in it. It would be nice to be able
to dial up a temperature and fill a bath, and not have to wait for the
shower to stabilise its temperature, but is it worth the expense of
duplication for such wonders of science?
Brian

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"Dan S. MacAbre" wrote in message
news
Chris Hogg wrote:
On Mon, 12 Mar 2018 10:54:05 +0000, "Dan S. MacAbre"
wrote:

Now that the weather is warming up, I'm considering replacing our HW
storage tank (it's about 30 years old, and is getting a bit crusty
around some of the pipe connectors). Before I do, I suppose I ought to
ask if (in everyone's opinion) I should just replace it like-for-like?
Or is there some other direction I ought to be heading in, like
mains-pressure hot water, or just using instant hot-water taps
everywhere instead? Or something else?


We've just had a traditional sixty-year-old DHW system replaced by an
unvented, mains-pressure system in my late mother's bungalow, which we
intend to move into soon. Several comments:

It's based on a Joule tank,
http://bit.ly/2Ht27Gz . The plumbing seems
a lot more complicated than before, with pressure regulators,
expansion vessels, pressure relief valves, tundishes etc all over the
place. The airing cupboard is now a cat's cradle of pipework. Whether
it could be simpler, I don't know. I think it all has to be installed
by a specialist, rather than DIY, BIMBW.

The DHW cylinder itself is much bigger that I expected; this may just
be what the plumber chose to install, rather than being necessary. My
comment to the plumber was that it looked like a section from a Saturn
5 rocket.

A potential disadvantage is that in very cold weather, such as we've
just had and where the mains supply may be off for several days, is
that you have no water at all. At least in our present place when the
water was cut off for 36 hours, we could draw down the water from the
tank in the loft, boiled where appropriate, but that wouldn't be an
option with an unvented system unless some way was found of retaining
the tank, in which case why bother with an unvented system at all.


Well, it's not like we have any problems with what there is now. We
occasionally need to switch on an immersion heater (our little boy has
several baths a day - he likes to play with his toy ships), and the
upstairs hot water pressure is a bit low (but I put a pump in, so it's
okay). It's just that sometimes, thinking of selling the house in the
future, everything might be a bit 'old-fashioned'. The thought of
mains-pressure HW does seem a little scary. And I don't really like
over-complicated things (which is why we still have the 30 year old
boiler).





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Default Replacing copper HW tank.

Unless you have cause to think the crusty pipe connections may fail I'd suggest you don't fix what isn't busted.
Do note that installing an unvented cylinder should be done by a competent and certified installer. Incorrectly installed it is a potential bomb.
I think there's a requirement for building regs approval for swapping a vented one now as it comes under conservation of energy but iirc prelagged complies as long as the temperature controls are up to date and immersion stat is compliant.
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Default Replacing copper HW tank.

On 12/03/2018 10:54, Dan S. MacAbre wrote:
Now that the weather is warming up, I'm considering replacing our HW
storage tank (it's about 30 years old, and is getting a bit crusty
around some of the pipe connectors).Â* Before I do, I suppose I ought to
ask if (in everyone's opinion) I should just replace it like-for-like?
Or is there some other direction I ought to be heading in, like
mains-pressure hot water, or just using instant hot-water taps
everywhere instead?Â* Or something else?


I replaced my hot water tank with one that came covered with 2" of foam
which I then painted. Much better than the previous jacket. I like
having an immersion heater as a backup in case my boiler is not working.

I did get something for the old copper tank, based on weight a lot of
which was crud.


--
Michael Chare
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Default Replacing copper HW tank.

John Rumm wrote:

On 12/03/2018 12:46, Roger Hayter wrote:
John Rumm wrote:

On 12/03/2018 11:25, Chris Hogg wrote:

We've just had a traditional sixty-year-old DHW system replaced by an
unvented, mains-pressure system in my late mother's bungalow, which we
intend to move into soon. Several comments:

It's based on a Joule tank, http://bit.ly/2Ht27Gz . The plumbing seems
a lot more complicated than before, with pressure regulators,
expansion vessels, pressure relief valves, tundishes etc all over the
place. The airing cupboard is now a cat's cradle of pipework. Whether
it could be simpler, I don't know.

Here is the basic layout you can expect:

http://wiki.diyfaq.org.uk/index.php/...nts_of_an_unve
nted_cylinder

I think it all has to be installed
by a specialist, rather than DIY, BIMBW.

Historically it was the case that only unvented cylinders were covered
by building regs (Part 3 document G). These days *all* cylinders are
covered by the building regs. See approved document G for more info.

They also need to be installed by someone who knows what they are doing!
(although that applies to any cylinder - unvented ones may be less well
understood by some plumbers).

Modern installs should also include things like mixing valves to limit
the maximum temperature at the point of use, but again that applies to
all stored water systems.

The DHW cylinder itself is much bigger that I expected; this may just
be what the plumber chose to install, rather than being necessary. My
comment to the plumber was that it looked like a section from a Saturn
5 rocket.

Yup unvented cylinders are often available in larger capacities than
traditional ones. (although you can still do the same trick doubling up
smaller cylinders like you can with a vented system to get more capacity)

Personally I fitted a 210L one which is probably about 5' tall. The
outer shell and integral insulation can make them look a bit more
"solid" than a normal tank. If I were doing it again, I might go for the
next size up.

A potential disadvantage is that in very cold weather, such as we've
just had and where the mains supply may be off for several days, is
that you have no water at all. At least in our present place when the
water was cut off for 36 hours, we could draw down the water from the
tank in the loft, boiled where appropriate, but that wouldn't be an
option with an unvented system unless some way was found of retaining
the tank, in which case why bother with an unvented system at all.

Sometimes upgrading the connection to the mains is way of solving a
number of related problems (lack of flow rate, freezing etc). A nice
32mm MDPE pipe buried deep enough ought not freeze and will make any
mains pressure water system work much better usually.


As a matter of interest, do you think that is likely to be worth doing
if the water board side connection is 2m of 25mm?


You mean using a larger pipe than theirs? It depends on the
circumstances... If you have say 40m of 1/2" pipe after that, Then any
increase will make a significant difference. The cost of the pipe is
usually only a small part of the overall cost of swapping it, so you may
as well over rather than under spec it.

(Flow resistance is a function of both diameter and length so a short
run of something narrower is not necessarily a show stopper)


I just put in about 8m of 25mm, but you're making me wonder if I should
have used 32mm!

--

Roger Hayter
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Default Replacing copper HW tank.

On 12/03/2018 10:54, Dan S. MacAbre wrote:
Now that the weather is warming up, I'm considering replacing our HW
storage tank (it's about 30 years old, and is getting a bit crusty
around some of the pipe connectors).Â* Before I do, I suppose I ought to
ask if (in everyone's opinion) I should just replace it like-for-like?
Or is there some other direction I ought to be heading in, like
mains-pressure hot water, or just using instant hot-water taps
everywhere instead?Â* Or something else?



The new tank is likely to come with a integral foam insulation jacket so
if replacing like with like capacity wise you may need more space for
the new tank.

--
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Default Replacing copper HW tank.

On 12/03/2018 18:10, Michael Chare wrote:

I did get something for the old copper tank, based on weight a lot of
which was crud.


When they changed our cylinder the weight of crud combined with
corrosion was enough for the bottom to fall out...

In theory the new one will give you hot water continuously. The coil
will absorb all the heat the boiler can give.

Andy.


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On 12/03/2018 15:47, Cynic wrote:
Unless you have cause to think the crusty pipe connections may fail
I'd suggest you don't fix what isn't busted. Do note that installing
an unvented cylinder should be done by a competent and certified
installer.



Incorrectly installed it is a potential bomb.


While often stated, I am not convinced this is anything other than a bit
of FUD that serves the makers of combis etc well. Yes you can turn one
into a bomb in theory, but you would have to try *really* hard...

Firstly you are not going to super heat any cylinder with a boiler as
the primary heat source. So you would need to use an immersion as the
primary heat source.

Secondly, they come pre equipped with at least two safety interlocks
(over temperature and over pressure relief valves). You would have to
defeat both.

Lastly the immersion heaters also come with a thermostatic control and
separate overheat protection. You would need to defeat both of those also.

(probably worth keeping in mind that an vented cylinder can kill you as
well)

I think
there's a requirement for building regs approval for swapping a
vented one now as it comes under conservation of energy but iirc
prelagged complies as long as the temperature controls are up to date
and immersion stat is compliant.


It also comes under G3 - where the proper venting requirements,
sanitation protection, and thermostatic mixing requirements are specified.

https://www.planningportal.co.uk/inf...ter_efficiency



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Default Replacing copper HW tank.

On 12/03/2018 16:21, Chris Hogg wrote:
On Mon, 12 Mar 2018 12:54:13 +0000, Chris Hogg wrote:

On Mon, 12 Mar 2018 11:38:40 +0000, "Dan S. MacAbre"
wrote:
The thought of mains-pressure HW does seem a little scary. And I don't really like
over-complicated things (which is why we still have the 30 year old boiler).


The tank suppliers require the tank pressure to be below some maximum
figure, 3 bar in our case, controlled with a pressure reducer, so it
doesn't necessarily run at mains pressure.
http://www.jouleuk.co.uk/product/inl...-group-valves/

But we also have a reducer on the incoming mains. I don't know what
it's set to, it has no gauge (but that is due to be remedied!).

There is also an expansion vessel on the DHW, as well as one on the
CH.


TBH, if when making the decision to stick with a new conventional
vented system or go unvented, I knew then what I know now, I wouldn't
have changed. By all means replace the tank if you think it needs it,
but leave all else alone. IIABDFI.


In comparison, I made the change and am very pleased with the (massive)
improvement in performance...

It really all depends on the circumstances...


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John.

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Default Replacing copper HW tank.

On 12/03/2018 18:10, Michael Chare wrote:
On 12/03/2018 10:54, Dan S. MacAbre wrote:
Now that the weather is warming up, I'm considering replacing our HW
storage tank (it's about 30 years old, and is getting a bit crusty
around some of the pipe connectors).Â* Before I do, I suppose I ought
to ask if (in everyone's opinion) I should just replace it
like-for-like? Or is there some other direction I ought to be heading
in, like mains-pressure hot water, or just using instant hot-water
taps everywhere instead?Â* Or something else?


I replaced my hot water tank with one that came covered with 2" of foam
which I then painted. Much better than the previous jacket.


Pre-insulated is nice - except then the previous tank is in a cupboard
that is big enough for the new tank, but not big enough to manouevre it
in. I had to cut of half-a-dozen central heating pipes and remove valves
and pump to get the tank in and then rejoin all the pipes.

I like
having an immersion heater as a backup in case my boiler is not working.


Me too, but ours has failed in an odd way. I am asumming that the
element has warped towards the stat tube. It works once and trips out
the overheat trip. I have replaced the stat a couple of times and the
problem remains. Of course the heater has siezed into the tank and will
not come out.

At least I can reset it and use it once if we really need to.

SteveW
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On Monday, 12 March 2018 22:14:36 UTC, Steve Walker wrote:
On 12/03/2018 18:10, Michael Chare wrote:
On 12/03/2018 10:54, Dan S. MacAbre wrote:


Now that the weather is warming up, I'm considering replacing our HW
storage tank (it's about 30 years old, and is getting a bit crusty
around some of the pipe connectors).Â* Before I do, I suppose I ought
to ask if (in everyone's opinion) I should just replace it
like-for-like? Or is there some other direction I ought to be heading
in, like mains-pressure hot water, or just using instant hot-water
taps everywhere instead?Â* Or something else?


I replaced my hot water tank with one that came covered with 2" of foam
which I then painted. Much better than the previous jacket.


Pre-insulated is nice - except then the previous tank is in a cupboard
that is big enough for the new tank, but not big enough to manouevre it
in. I had to cut of half-a-dozen central heating pipes and remove valves
and pump to get the tank in and then rejoin all the pipes.

I like
having an immersion heater as a backup in case my boiler is not working..


Me too, but ours has failed in an odd way. I am asumming that the
element has warped towards the stat tube. It works once and trips out
the overheat trip. I have replaced the stat a couple of times and the
problem remains. Of course the heater has siezed into the tank and will
not come out.

At least I can reset it and use it once if we really need to.

SteveW


Have you tried automatic transmission fluid? It's an awesome unsiezer
Might be easier to just use a separate stat. Must be 13A rated.


NT
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Default Replacing copper HW tank.

On 12/03/2018 22:21, wrote:
On Monday, 12 March 2018 22:14:36 UTC, Steve Walker wrote:
On 12/03/2018 18:10, Michael Chare wrote:
On 12/03/2018 10:54, Dan S. MacAbre wrote:


Now that the weather is warming up, I'm considering replacing our HW
storage tank (it's about 30 years old, and is getting a bit crusty
around some of the pipe connectors).Â* Before I do, I suppose I ought
to ask if (in everyone's opinion) I should just replace it
like-for-like? Or is there some other direction I ought to be heading
in, like mains-pressure hot water, or just using instant hot-water
taps everywhere instead?Â* Or something else?

I replaced my hot water tank with one that came covered with 2" of foam
which I then painted. Much better than the previous jacket.


Pre-insulated is nice - except then the previous tank is in a cupboard
that is big enough for the new tank, but not big enough to manouevre it
in. I had to cut of half-a-dozen central heating pipes and remove valves
and pump to get the tank in and then rejoin all the pipes.

I like
having an immersion heater as a backup in case my boiler is not working.


Me too, but ours has failed in an odd way. I am asumming that the
element has warped towards the stat tube. It works once and trips out
the overheat trip. I have replaced the stat a couple of times and the
problem remains. Of course the heater has siezed into the tank and will
not come out.

At least I can reset it and use it once if we really need to.

SteveW


Have you tried automatic transmission fluid? It's an awesome unsiezer
Might be easier to just use a separate stat. Must be 13A rated.


I could use an external stat, but I'd also need to add an external
overtemp trip. The other option is to cut a hole in the tank and add a
new boss.

SteveW


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On Monday, 12 March 2018 22:46:25 UTC, Steve Walker wrote:
On 12/03/2018 22:21, tabbypurr wrote:
On Monday, 12 March 2018 22:14:36 UTC, Steve Walker wrote:
On 12/03/2018 18:10, Michael Chare wrote:
On 12/03/2018 10:54, Dan S. MacAbre wrote:


Now that the weather is warming up, I'm considering replacing our HW
storage tank (it's about 30 years old, and is getting a bit crusty
around some of the pipe connectors).Â* Before I do, I suppose I ought
to ask if (in everyone's opinion) I should just replace it
like-for-like? Or is there some other direction I ought to be heading
in, like mains-pressure hot water, or just using instant hot-water
taps everywhere instead?Â* Or something else?

I replaced my hot water tank with one that came covered with 2" of foam
which I then painted. Much better than the previous jacket.

Pre-insulated is nice - except then the previous tank is in a cupboard
that is big enough for the new tank, but not big enough to manouevre it
in. I had to cut of half-a-dozen central heating pipes and remove valves
and pump to get the tank in and then rejoin all the pipes.

I like
having an immersion heater as a backup in case my boiler is not working.

Me too, but ours has failed in an odd way. I am asumming that the
element has warped towards the stat tube. It works once and trips out
the overheat trip. I have replaced the stat a couple of times and the
problem remains. Of course the heater has siezed into the tank and will
not come out.

At least I can reset it and use it once if we really need to.

SteveW


Have you tried automatic transmission fluid? It's an awesome unsiezer
Might be easier to just use a separate stat. Must be 13A rated.


I could use an external stat, but I'd also need to add an external
overtemp trip. The other option is to cut a hole in the tank and add a
new boss.

SteveW


You only need to wire over one stat & replace it with external.

Another option is to run it on reduced voltage if you have a 1kVA 110v transformer. Wise to overrate it as it'll run for over an hour at a time.


NT
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On 12/03/18 22:09, John Rumm wrote:
In comparison, I made the change and am very pleased with the (massive)
improvement in performance...

It really all depends on the circumstances...


The thought of going bacl to header tanks and low pressure hot water
just amuses me really.


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On 13/03/2018 03:05, The Natural Philosopher wrote:
On 12/03/18 22:09, John Rumm wrote:
In comparison, I made the change and am very pleased with the
(massive) improvement in performance...

It really all depends on the circumstances...


The thought of going bacl to header tanks and low pressure hot water
just amuses me really.


If you already have a vented system that works well, a fast recovery
cylinder, and have pumps installed for showers, then there is not much
value to be had ripping and replacing it for the sake of it.

In my case the existing system did not work at all in some respects and
was ill suited to the property. The only shower pump had died long ago.
So it was a no brainer since I was changing the boiler anyway.


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On Tuesday, 13 March 2018 10:04:23 UTC, John Rumm wrote:
On 13/03/2018 03:05, The Natural Philosopher wrote:
On 12/03/18 22:09, John Rumm wrote:


In comparison, I made the change and am very pleased with the
(massive) improvement in performance...

It really all depends on the circumstances...


The thought of going bacl to header tanks and low pressure hot water
just amuses me really.


If you already have a vented system that works well, a fast recovery
cylinder, and have pumps installed for showers, then there is not much
value to be had ripping and replacing it for the sake of it.

In my case the existing system did not work at all in some respects and
was ill suited to the property. The only shower pump had died long ago.
So it was a no brainer since I was changing the boiler anyway.


Some vented systems work fine with slow recovery and no pump. As said there's only a reason to rework them when they don't work.


NT
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On 12/03/2018 10:54, Dan S. MacAbre wrote:
Now that the weather is warming up, I'm considering replacing our HW
storage tank (it's about 30 years old, and is getting a bit crusty
around some of the pipe connectors).Â* Before I do, I suppose I ought to
ask if (in everyone's opinion) I should just replace it like-for-like?
Or is there some other direction I ought to be heading in, like
mains-pressure hot water, or just using instant hot-water taps
everywhere instead?Â* Or something else?


Mine is the houses original tank from 1976 and there is
nothing wrong with it.

Is this a case of 'it aint broke so why fix it' ?,
especially since you are only contemplating a
like-for-like swap. If there is space and you have
the possibility of some form of solar panel too
(and are young enough to get any financial benefit)
then a larger tank that has dual heating coils might
be worthwhile upgrade, but do the maths.

Are your joists strong enough to support a much larger
tank, something that people don't consider ?.

More information would help like :-

Age and size of property
Number of people and age
Number of bathrooms and distance from hot tank.
Type of heating appliance.






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On 13/03/2018 07:53, Chris Hogg wrote:
On Mon, 12 Mar 2018 22:09:29 +0000, John Rumm
wrote:

On 12/03/2018 16:21, Chris Hogg wrote:

TBH, if when making the decision to stick with a new conventional
vented system or go unvented, I knew then what I know now, I wouldn't
have changed. By all means replace the tank if you think it needs it,
but leave all else alone. IIABDFI.


In comparison, I made the change and am very pleased with the (massive)
improvement in performance...

It really all depends on the circumstances...


I'll look forward to that now we've got it installed anyway.


How do you know your heating engineer (and I hope has was,
and not just a plumber) didn't just specify the solution that
gave him the highest markup ?.

For mains pressure tanks he needs an extra certificate that
J Bloggs, overpriced-tap-washers-r-us doesn't have.
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On 12/03/2018 12:19, John Rumm wrote:
Personally I fitted a 210L one which is probably about 5' tall.


If I replaced my bog standard tank with one of those, bearing
in mind the appalling way the 1st floor joists were attached with
joist hangers (4 or 5, 4 inch round nails half in and then bashed over),
it might end up in the lounge.

There is already 20mm ceiling deflection where the tank is !!




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On 12/03/2018 22:03, John Rumm wrote:
On 12/03/2018 15:47, Cynic wrote:
Unless you have cause to think the crusty pipe connections may fail
I'd suggest you don't fix what isn't busted. Do note that installing
an unvented cylinder should be done by a competent and certified
installer.



Incorrectly installed it is a potential bomb.


While often stated, I am not convinced this is anything other than a bit
of FUD that serves the makers of combis etc well. Yes you can turn one
into a bomb in theory, but you would have to try *really* hard...

Firstly you are not going to super heat any cylinder with a boiler as
the primary heat source. So you would need to use an immersion as the
primary heat source.

Secondly, they come pre equipped with at least two safety interlocks
(over temperature and over pressure relief valves). You would have to
defeat both.

Lastly the immersion heaters also come with a thermostatic control and
separate overheat protection. You would need to defeat both of those also.

(probably worth keeping in mind that an vented cylinder can kill you as
well)

I think
there's a requirement for building regs approval for swapping a
vented one now as it comes under conservation of energy but iirc
prelagged complies as long as the temperature controls are up to date
and immersion stat is compliant.


It also comes under G3 - where the proper venting requirements,
sanitation protection, and thermostatic mixing requirements are specified.

https://www.planningportal.co.uk/inf...ter_efficiency




What happned to the thermostatic control that limits the temp at the
tap to no more than ?50. Did this ever become a building regs
requirement ?.
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On 12/03/2018 18:10, Michael Chare wrote:
On 12/03/2018 10:54, Dan S. MacAbre wrote:
Now that the weather is warming up, I'm considering replacing our HW
storage tank (it's about 30 years old, and is getting a bit crusty
around some of the pipe connectors).Â* Before I do, I suppose I ought
to ask if (in everyone's opinion) I should just replace it
like-for-like? Or is there some other direction I ought to be heading
in, like mains-pressure hot water, or just using instant hot-water
taps everywhere instead?Â* Or something else?


I replaced my hot water tank with one that came covered with 2" of foam
which I then painted. Much better than the previous jacket. I like
having an immersion heater as a backup in case my boiler is not working.

I did get something for the old copper tank, based on weight a lot of
which was crud.



Another neighbour who fell for the BG 'No parts' scam had their
baxi bermuda replaced by a WB Junior ??12RI. Wife decided that
they 'needed' a new tank with more insulation and the one used
seemed to have about 4 inches of foam. It only just fitted through
the airing cupboard door afaik.

They also had a fancy wireless stat that has been replaced three
times. BG say it is their fault because they opted out of the
£12 per month 'option' to allow BG to dial in and reset it
remotely !. BG claim that this boiler won't work with a conventional
room stat. This I think is pork-pies.


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On 13/03/2018 15:21, Andrew wrote:
On 12/03/2018 22:03, John Rumm wrote:
On 12/03/2018 15:47, Cynic wrote:



I think
there's a requirement for building regs approval for swapping a
vented one now as it comes under conservation of energy but iirc
prelagged complies as long as the temperature controls are up to date
and immersion stat is compliant.


It also comes under G3 - where the proper venting requirements,
sanitation protection, and thermostatic mixing requirements are
specified.

https://www.planningportal.co.uk/inf...ter_efficiency




What happned to the thermostatic control that limits the temp at the
tap to no more than ?50. Did this ever become a building regs
requirement ?.


From the doc above:

Prevention of scalding
3.65 The hot water supply temperature to a bath should be limited to a
maximum of 48°C by use of an in-line blending valve or other appropriate
temperature control device, with a maximum temperature stop and a
suitable arrangement of pipework.

and also:

Prevention of excessive temperatures
3.64 Where the operating temperature of domestic hot water in the
storage vessel in a dwelling is capable of exceeding 80°C under normal
operating conditions (a situation that may occur in vessels used as heat
stores and those connected to solar heat collectors or solid fuel
boilers that do not have intervening controls between the boiler and the
vessel containing the hot water) the outlet from the storage vessel
should be fitted with a device, such as an in-line hot water supply
tempering valve in accordance with BS EN 15092:2008 Building Valves.
In-line hot water tempering valves, to ensure that the temperature
supplied to the domestic hot water distribution system does not exceed 60°C.


--
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John.

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Michael Chare wrote:

I replaced my hot water tank with one that came covered with 2" of foam
which I then painted. Much better than the previous jacket. I like
having an immersion heater as a backup in case my boiler is not working.


My similar foamed tank is in the integral garage and I wondered
if there was any point in adding any extra insulation? There
isn't a lot of clearance, but I suppose I might drape something
over the top similar to the old jackets.

Chris
--
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Plant amazing Acers.
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On Tuesday, 13 March 2018 19:54:02 UTC, Chris J Dixon wrote:
Michael Chare wrote:

I replaced my hot water tank with one that came covered with 2" of foam
which I then painted. Much better than the previous jacket. I like
having an immersion heater as a backup in case my boiler is not working.


My similar foamed tank is in the integral garage and I wondered
if there was any point in adding any extra insulation? There
isn't a lot of clearance, but I suppose I might drape something
over the top similar to the old jackets.

Chris


If it's in a cupboard the space can be packed with junk insulation, avoiding any flex feeding he immersion. If no cupboard it's easy to construct a flimsy outer wrap that can be stuffed with insulating junk, or apply roll insulation & tie.


NT
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There are as you suggest "safety features but unless correctly installed and commissioned the risk remains. Too many bodge artists out there!
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On 13/03/2018 10:04, John Rumm wrote:
On 13/03/2018 03:05, The Natural Philosopher wrote:
On 12/03/18 22:09, John Rumm wrote:
In comparison, I made the change and am very pleased with the
(massive) improvement in performance...

It really all depends on the circumstances...


The thought of going bacl to header tanks and low pressure hot water
just amuses me really.


If you already have a vented system that works well, a fast recovery
cylinder, and have pumps installed for showers, then there is not much
value to be had ripping and replacing it for the sake of it.


+1

When I went from a combi (I already had a separate vented immersion tank
running a shower) to a system boiler, I just put in an ordinary modern
cylinder with heating coil, not a special fast recovery one. Plus an ST
pump for DHW, and a double ST for the shower.

Much less complication and no problem with recovery times.


In my case the existing system did not work at all in some respects and
was ill suited to the property. The only shower pump had died long ago.
So it was a no brainer since I was changing the boiler anyway.





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On 17/03/2018 21:36, newshound wrote:
On 13/03/2018 10:04, John Rumm wrote:
On 13/03/2018 03:05, The Natural Philosopher wrote:
On 12/03/18 22:09, John Rumm wrote:
In comparison, I made the change and am very pleased with the
(massive) improvement in performance...

It really all depends on the circumstances...

The thought of going bacl to header tanks and low pressure hot water
just amuses me really.


If you already have a vented system that works well, a fast recovery
cylinder, and have pumps installed for showers, then there is not much
value to be had ripping and replacing it for the sake of it.


+1

When I went from a combi (I already had a separate vented immersion tank
running a shower) to a system boiler, I just put in an ordinary modern
cylinder with heating coil, not a special fast recovery one. Plus an ST
pump for DHW, and a double ST for the shower.

Much less complication


I would have thought if you need to replace a cylinder and install two
pumps, I am not sure that really qualifies under the "less complexity"
category!

and no problem with recovery times.


If its a relatively recent one, then it will be fairly quick recovery
anyway. How the system is zoned will also have a big influence on
recovery times.


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John.

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On 17/03/2018 21:08, Cynic wrote:

There are as you suggest "safety features but unless correctly installed and commissioned the risk remains. Too many bodge artists out there!


Well the bodge artists are easy to dodge, install it yourself, then you
know its done right!

The safety features on the cylinders don't need commissioning as such -
beyond a quick twist of the test knobs to check they pass water to the
tundish.

There is a valve assembly on the inlet that usually combines a strainer,
pressure reduction valve, pressure relief valve, connection to the
expansion vessel, and outlets to the cold feed on the cylinder and a
balanced pressure cold feed available for use elsewhere. I suppose you
could install it backwards, but it would probably just result in a
system that does not work at all. The side mounted overtemp/pressure
valve is a special fitting that nothing else is supposed to fit. So it
would be difficult to omit it. I suppose you could connect it to a pipe
and blank it off, but that would still in the grand scheme of things be
less dangerous than say blanking off the vent on the vented cylinder.

The risk of a steam explosion does not exist with indirectly heated
unvented cylinders - you need either immersion heaters, or an
inappropriate connection to a solid fuel stove etc. (plus the defeat of
all the interlocks).

You can bodge dangerous hot water systems of all types (and the dangers
are not usually ones of explosion, but include leaking, flooding,
scalding, breeding legionella, back contamination of the mains supply,
and tanks falling through ceilings etc).


--
Cheers,

John.

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On 18/03/2018 13:51, John Rumm wrote:
On 17/03/2018 21:36, newshound wrote:
On 13/03/2018 10:04, John Rumm wrote:
On 13/03/2018 03:05, The Natural Philosopher wrote:
On 12/03/18 22:09, John Rumm wrote:
In comparison, I made the change and am very pleased with the
(massive) improvement in performance...

It really all depends on the circumstances...

The thought of going bacl to header tanks and low pressure hot water
just amuses me really.

If you already have a vented system that works well, a fast recovery
cylinder, and have pumps installed for showers, then there is not much
value to be had ripping and replacing it for the sake of it.


+1

When I went from a combi (I already had a separate vented immersion tank
running a shower) to a system boiler, I just put in an ordinary modern
cylinder with heating coil, not a special fast recovery one. Plus an ST
pump for DHW, and a double ST for the shower.

Much less complication


I would have thought if you need to replace a cylinder and install two
pumps, I am not sure that really qualifies under the "less complexity"
category!


No, I already had the shower pump plumbed in to the old cylinder. Even
so I'd have said there was more plumbing and electrics with a vented system.


and no problem with recovery times.


If its a relatively recent one, then it will be fairly quick recovery
anyway. How the system is zoned will also have a big influence on
recovery times.


I will admit I gave the cylinder full priority when it needs heat (Is
that W rather than Y plan? ICBA to look it up.

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Default Replacing copper HW tank.

On 18/03/2018 16:16, newshound wrote:
On 18/03/2018 13:51, John Rumm wrote:
On 17/03/2018 21:36, newshound wrote:
On 13/03/2018 10:04, John Rumm wrote:
On 13/03/2018 03:05, The Natural Philosopher wrote:
On 12/03/18 22:09, John Rumm wrote:
In comparison, I made the change and am very pleased with the
(massive) improvement in performance...

It really all depends on the circumstances...

The thought of going bacl to header tanks and low pressure hot water
just amuses me really.

If you already have a vented system that works well, a fast recovery
cylinder, and have pumps installed for showers, then there is not much
value to be had ripping and replacing it for the sake of it.

+1

When I went from a combi (I already had a separate vented immersion tank
running a shower) to a system boiler, I just put in an ordinary modern
cylinder with heating coil, not a special fast recovery one. Plus an ST
pump for DHW, and a double ST for the shower.

Much less complication


I would have thought if you need to replace a cylinder and install two
pumps, I am not sure that really qualifies under the "less complexity"
category!


No, I already had the shower pump plumbed in to the old cylinder. Even
so I'd have said there was more plumbing and electrics with a vented
system.


Electrics about the same[1], plumbing; Vented has a feed from a cold
cistern plus a vent (plus additional feeds to each shower ideally).
Unvented does not need those - just a feed from the mains, but it does
need a separate discharge pipe and then (short) connection to an
expansion vessel.

[1] Some have an additional over temp stat that you can put into service
as a backup backup system.

and no problem with recovery times.


If its a relatively recent one, then it will be fairly quick recovery
anyway. How the system is zoned will also have a big influence on
recovery times.


I will admit I gave the cylinder full priority when it needs heat (Is
that W rather than Y plan? ICBA to look it up.


Yup, W is like Y plan but with a diversion valve rather than a mid
position valve.


--
Cheers,

John.

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