Hi,

I've got a hot water tank (approx 4' high) and it's currently got a tiny
immersion heater element (11" from what I can guess off the label and
also the pitiful amount of water that a single heating produces).

I would like to replace it to enable it to heat the majority/entire
tank. Is there any rule of thumb/limit on what length of heater you can
use versus the size/height of the tank?

Andy

On Fri, 07 Nov 2008 11:08:15 +0000, Andy Kirkland
wrote:

Hi,

I've got a hot water tank (approx 4' high) and it's currently got a tiny
immersion heater element (11" from what I can guess off the label and
also the pitiful amount of water that a single heating produces).

I would like to replace it to enable it to heat the majority/entire
tank. Is there any rule of thumb/limit on what length of heater you can
use versus the size/height of the tank?

Andy

Can't you just measure the depth of the tank and buy one to fit ,like
a 24 " one for example.
I'm assuming there is enough room above the tank to let you get a
longer one in .

wrote:
On Fri, 07 Nov 2008 11:08:15 +0000, Andy Kirkland
wrote:

Hi,

I've got a hot water tank (approx 4' high) and it's currently got a tiny
immersion heater element (11" from what I can guess off the label and
also the pitiful amount of water that a single heating produces).

I would like to replace it to enable it to heat the majority/entire
tank. Is there any rule of thumb/limit on what length of heater you can
use versus the size/height of the tank?

Andy

Can't you just measure the depth of the tank and buy one to fit ,like
a 24 " one for example.
I'm assuming there is enough room above the tank to let you get a
longer one in .

I was working on that theory.... I should be able to get a 36" element
in. I was just wondering if there were any guidelines regarding length
of element/proximity to side of tank etc.

Andy

On Fri, 07 Nov 2008 11:53:34 +0000, Andy Kirkland
wrote:

wrote:
On Fri, 07 Nov 2008 11:08:15 +0000, Andy Kirkland
wrote:

Hi,

I've got a hot water tank (approx 4' high) and it's currently got a tiny
immersion heater element (11" from what I can guess off the label and
also the pitiful amount of water that a single heating produces).

I would like to replace it to enable it to heat the majority/entire
tank. Is there any rule of thumb/limit on what length of heater you can
use versus the size/height of the tank?

Andy

Can't you just measure the depth of the tank and buy one to fit ,like
a 24 " one for example.
I'm assuming there is enough room above the tank to let you get a
longer one in .

I was working on that theory.... I should be able to get a 36" element
in. I was just wondering if there were any guidelines regarding length
of element/proximity to side of tank etc.

Andy

I'm assuming that the immerser fits straight down the middle ( or does
it?) .If so then it won't be any nearer the sides than the old one .
I know that some fit in sideways and some ( I think) are at an angle .
You still have 12" between the end and the foot of the tank ( less an
amount for any concave in the bottom of the tank which you won't be
able to see unless you remove the tank )and allowing for any sludge at
the foot of the tank .
Does this help...it suggests 27" is the most common size
http://wiki.diyfaq.org.uk/index.php?...s#Element_Size

In an earlier contribution to this discussion,
Andy Kirkland wrote:

Hi,

I've got a hot water tank (approx 4' high) and it's currently got a
tiny immersion heater element (11" from what I can guess off the
label and also the pitiful amount of water that a single heating
produces).
I would like to replace it to enable it to heat the majority/entire
tank. Is there any rule of thumb/limit on what length of heater you
can use versus the size/height of the tank?

Andy

One thing is certain - any water *below* the element won't get heated
significantly by it.

If it goes in horizontally near the bottom of the cylinder, length doesn't
matter too much - but it makes sense to get one whose length is just short
of the cylinder diameter.

If it goes in (near) vertically from the top, you need one which extends as
far down as you can get. I doubt whether you can get one that's anywhere
near 4' long.

I assume that the immersion heater isn't your *only* way of heating the
water, and that the cylinder also has an internal coil carrying hot water
from a gas boiler boiler or somesuch as the principal means of heating the
DHW?
--
Cheers,
Roger
______
Email address maintained for newsgroup use only, and not regularly
monitored.. Messages sent to it may not be read for several weeks.
PLEASE REPLY TO NEWSGROUP!

On Fri, 07 Nov 2008 11:08:15 +0000, Andy Kirkland
wrote:


I've got a hot water tank (approx 4' high) and it's currently got a tiny
immersion heater element (11" from what I can guess off the label and
also the pitiful amount of water that a single heating produces).

I would like to replace it to enable it to heat the majority/entire
tank.

Our (non-std size) direct cylinder was heated for years with an 11" 3kW heater
but it was fitted at the bottom of the tank so could heat the whole contents.
When I fitted a new indirect cylinder last year (standard 900 x 450mm B&Q type)
I also fitted a 27in immersion heater at the top.
I have posted a graph showing the temperatue at the top of the tank and at about
1/3 way from bottom. The lower trace shows a declining temperature (as the
central heating was turned off for the test) while the upper temperature was
cycling.
http://www.diy.110mb.com/imm27.jpg

If your cylinder is also indirectly heated from a CH boiler then the coil /may/
obstruct a longer immersion heater.

Geo

We were somewhere around Barstow, on the edge of the desert, when the
drugs began to take hold. I remember Andy Kirkland
saying something like:

I was working on that theory.... I should be able to get a 36" element
in. I was just wondering if there were any guidelines regarding length
of element/proximity to side of tank etc.

24" and 27" are commonly available. The 11" one you have is normally
used for side entry immersions.

We were somewhere around Barstow, on the edge of the desert, when the
drugs began to take hold. I remember Geo
saying something like:

If your cylinder is also indirectly heated from a CH boiler then the coil /may/
obstruct a longer immersion heater.

They're designed not too - although you wouldn't believe that from the
struggle you sometimes have to get the bloody thing in past the coil.

On Fri, 07 Nov 2008 15:51:01 +0000, Grimly Curmudgeon
wrote:

We were somewhere around Barstow, on the edge of the desert, when the
drugs began to take hold. I remember Geo
saying something like:

If your cylinder is also indirectly heated from a CH boiler then the coil /may/
obstruct a longer immersion heater.

They're designed not too - although you wouldn't believe that from the
struggle you sometimes have to get the bloody thing in past the coil.

Before I got a new boiler I had a Primatic and when the immerser
failed it was a bit of a struggle to get it out and the new one in
,not helped by the lack of space immediately above the tank between it
and floor of the flat above .

Grimly Curmudgeon wrote:

We were somewhere around Barstow, on the edge of the desert, when the
drugs began to take hold. I remember Geo
saying something like:

If your cylinder is also indirectly heated from a CH boiler then the coil
/may/ obstruct a longer immersion heater.

They're designed not too - although you wouldn't believe that from the
struggle you sometimes have to get the bloody thing in past the coil.

It sounds like you have done one before, so how did you get the old one
out?
I tried to get my mates out, but it wouldnt budge.
Alan.
--
To reply by e-mail, change the ' + ' to 'plus'.

"A.Lee" wrote in message
...
Grimly Curmudgeon wrote:

We were somewhere around Barstow, on the edge of the desert, when the
drugs began to take hold. I remember Geo
saying something like:

If your cylinder is also indirectly heated from a CH boiler then the
coil
/may/ obstruct a longer immersion heater.

They're designed not too - although you wouldn't believe that from the
struggle you sometimes have to get the bloody thing in past the coil.

It sounds like you have done one before, so how did you get the old one
out?
I tried to get my mates out, but it wouldnt budge.
Alan.

Black art and luck. Don't drain the system until it starts to budge - modern
tanks have very little strength when full and none at all when empty. Local
heating, Plus-Gas, sacrifice, prayer, incantations and the preparedness to
buy a new tank are essential.


--
Bob Mannix
(anti-spam is as easy as 1-2-3 - not

Thanks everyone for the info - will go for a 27" or 36" one.

Now to the task of removing the old one..... penetrating oil, wait, more
oil, wait, tap gently, more oil, wait, attach spanner, pray!

Cheers

Andy

On Fri, 07 Nov 2008 17:01:29 +0000, Andy Kirkland
wrote:

Thanks everyone for the info - will go for a 27" or 36" one.

Now to the task of removing the old one..... penetrating oil, wait, more
oil, wait, tap gently, more oil, wait, attach spanner, pray!

Cheers

Andy

Hope you'll be pleasantly surprised .Mine unscrewed quite easily
altho' it had been in years

Grimly Curmudgeon wrote:
We were somewhere around Barstow, on the edge of the desert, when the
drugs began to take hold. I remember Andy Kirkland
saying something like:

I was working on that theory.... I should be able to get a 36"
element in. I was just wondering if there were any guidelines
regarding length of element/proximity to side of tank etc.

24" and 27" are commonly available. The 11" one you have is normally
used for side entry immersions.

AIUI the 24"/27" does the heavy lifting & the 11" is just a top up. The 11"
one won't heat enough water fast enough for most domestic applications.


--
Dave - The Medway Handyman
www.medwayhandyman.co.uk

Bob Mannix wrote:
"A.Lee" wrote in message
...
Grimly Curmudgeon wrote:

We were somewhere around Barstow, on the edge of the desert, when
the drugs began to take hold. I remember Geo
saying something like:

If your cylinder is also indirectly heated from a CH boiler then
the coil
/may/ obstruct a longer immersion heater.

They're designed not too - although you wouldn't believe that from
the struggle you sometimes have to get the bloody thing in past the
coil.

It sounds like you have done one before, so how did you get the old
one out?
I tried to get my mates out, but it wouldnt budge.
Alan.

Black art and luck. Don't drain the system until it starts to budge -
modern tanks have very little strength when full and none at all when
empty. Local heating, Plus-Gas, sacrifice, prayer, incantations and
the preparedness to buy a new tank are essential.

The ring type flat spanners are all but useless. The box spanner type is
much better.


--
Dave - The Medway Handyman
www.medwayhandyman.co.uk

After serious thinking The Medway Handyman wrote :
AIUI the 24"/27" does the heavy lifting & the 11" is just a top up. The 11"
one won't heat enough water fast enough for most domestic applications.

They are all around 3Kw, so because the 11" ois only able to heat the
upper water levels, it would in fact heat it up much quicker than a
longer element. As hot water rises, the hot water produced would stay
at the top of the tank.

--
Regards,
Harry (M1BYT) (L)
http://www.ukradioamateur.co.uk

On Fri, 07 Nov 2008 18:03:20 GMT someone who may be "The Medway
Handyman" wrote this:-

AIUI the 24"/27" does the heavy lifting & the 11" is just a top up. The 11"
one won't heat enough water fast enough for most domestic applications.

Other than a bath, and perhaps a power shower, a short immersion
heater is fine for normal domestic use. It will heat up the top of
the cylinder rapidly enough to cope with demand.

Those who want deep baths, or are heating water overnight for
storage in a properly insulated cylinder, will consider a longer
heater.

If one wants both the whole cylinder and the top part to be heated
in different circumstances extra bosses can be fitted. I also have a
vague recollection of dual element immersion heaters which fit in
one boss, though I have never encountered one that I can remember.



--
David Hansen, Edinburgh
I will *always* explain revoked encryption keys, unless RIP prevents me
http://www.opsi.gov.uk/acts/acts2000/00023--e.htm#54

"A.Lee" wrote in message
...
Grimly Curmudgeon wrote:

We were somewhere around Barstow, on the edge of the desert, when the
drugs began to take hold. I remember Geo
saying something like:

If your cylinder is also indirectly heated from a CH boiler then the
coil
/may/ obstruct a longer immersion heater.

They're designed not too - although you wouldn't believe that from the
struggle you sometimes have to get the bloody thing in past the coil.

It sounds like you have done one before, so how did you get the old one
out?
I tried to get my mates out, but it wouldnt budge.
Alan.
--
To reply by e-mail, change the ' + ' to 'plus'.


I replaced my immersion heater once, using a lever with a piece of chain
attached to it.

Some 10-15 years later I removed the tank. It was impossible to get the
element out of the tank without damaging the tank.


--
Michael Chare

"David Hansen" wrote in message
...
On Fri, 07 Nov 2008 18:03:20 GMT someone who may be "The Medway
Handyman" wrote this:-

AIUI the 24"/27" does the heavy lifting & the 11" is just a top up. The
11"
one won't heat enough water fast enough for most domestic applications.

Other than a bath, and perhaps a power shower, a short immersion
heater is fine for normal domestic use. It will heat up the top of
the cylinder rapidly enough to cope with demand.

Those who want deep baths, or are heating water overnight for
storage in a properly insulated cylinder, will consider a longer
heater.

If one wants both the whole cylinder and the top part to be heated
in different circumstances extra bosses can be fitted. I also have a
vague recollection of dual element immersion heaters which fit in
one boss, though I have never encountered one that I can remember.

David Hansen, Edinburgh


There are still RedHeat Dual elements on sale. They have a long and short
element. The long one used to heat the whole tank on the over night tariff
and a small one for boost during the day. But they are usually fitted on
cylinders that have 4 inches of soft insulation around them. It is the only
way to make them economical enough to use.

Andy Kirkland wrote:
Thanks everyone for the info - will go for a 27" or 36" one.

Now to the task of removing the old one..... penetrating oil, wait, more
oil, wait, tap gently, more oil, wait, attach spanner, pray!

Hitting the spanner with a hammer is less likely to crumple the tank
than applying high sustained force IME... Good luck!

--
Cheers,

John.

/================================================== ===============\
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|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

The Medway Handyman wrote:
Bob Mannix wrote:
"A.Lee" wrote in message
...
Grimly Curmudgeon wrote:

We were somewhere around Barstow, on the edge of the desert, when
the drugs began to take hold. I remember Geo
saying something like:

If your cylinder is also indirectly heated from a CH boiler then
the coil
/may/ obstruct a longer immersion heater.
They're designed not too - although you wouldn't believe that from
the struggle you sometimes have to get the bloody thing in past the
coil.
It sounds like you have done one before, so how did you get the old
one out?
I tried to get my mates out, but it wouldnt budge.
Alan.
Black art and luck. Don't drain the system until it starts to budge -
modern tanks have very little strength when full and none at all when
empty. Local heating, Plus-Gas, sacrifice, prayer, incantations and
the preparedness to buy a new tank are essential.

The ring type flat spanners are all but useless. The box spanner type is
much better.

The ring type do have the advantage that you can wallop them easier, and
you are reasonably aligned with the screw thread (so less bending moment
on the tank). However once it is free and turning the box spanners are
indeed better.

--
Cheers,

John.

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

John Rumm wrote:
Andy Kirkland wrote:
Thanks everyone for the info - will go for a 27" or 36" one.

Now to the task of removing the old one..... penetrating oil, wait,
more oil, wait, tap gently, more oil, wait, attach spanner, pray!

Hitting the spanner with a hammer is less likely to crumple the tank
than applying high sustained force IME... Good luck!

Sounds like what we need is an impact driver-style[1] immersion heater
remover. :-)

[1] The modern, up-to-date, Drivel and Makita approved impact driver -
not the old lump and hammer type.

--
Rod

Hypothyroidism is a seriously debilitating condition with an insidious
onset.
Although common it frequently goes undiagnosed.
www.thyromind.info www.thyroiduk.org www.altsupportthyroid.org

"Rod" wrote in message
...
John Rumm wrote:
Andy Kirkland wrote:
Thanks everyone for the info - will go for a 27" or 36" one.

Now to the task of removing the old one..... penetrating oil, wait, more
oil, wait, tap gently, more oil, wait, attach spanner, pray!

Hitting the spanner with a hammer is less likely to crumple the tank than
applying high sustained force IME... Good luck!



Give some thought to preventing the replacement one from getting stuck -
Copaslip on the threads would be my choice. The washer does the sealing -
not the thread.

We were somewhere around Barstow, on the edge of the desert, when the
drugs began to take hold. I remember "The Medway Handyman"
saying something like:


AIUI the 24"/27" does the heavy lifting & the 11" is just a top up. The 11"
one won't heat enough water fast enough for most domestic applications.

I have a pair of 3kW 11"ers, so they're as good as the long jobs.

We were somewhere around Barstow, on the edge of the desert, when the
drugs began to take hold. I remember David Hansen
saying something like:

If one wants both the whole cylinder and the top part to be heated
in different circumstances extra bosses can be fitted. I also have a
vague recollection of dual element immersion heaters which fit in
one boss, though I have never encountered one that I can remember.

They're the most common type I've encountered, so I don't know where you
mean.

John wrote:
"Rod" wrote in message
...
John Rumm wrote:
Andy Kirkland wrote:
Thanks everyone for the info - will go for a 27" or 36" one.

Now to the task of removing the old one..... penetrating oil, wait, more
oil, wait, tap gently, more oil, wait, attach spanner, pray!
Hitting the spanner with a hammer is less likely to crumple the tank than
applying high sustained force IME... Good luck!


Give some thought to preventing the replacement one from getting stuck -
Copaslip on the threads would be my choice. The washer does the sealing -
not the thread.

Got a feeling the most recent one I fitted did not have a washer, and
did seem to expect you to get a seal partly on the thread. Right PITA to
stop it leaking it was as well. Had to resort to real hemp and boss
white to get a workable seal.

--
Cheers,

John.

/================================================== ===============\
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| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

In article ,
John Rumm wrote:
Got a feeling the most recent one I fitted did not have a washer, and
did seem to expect you to get a seal partly on the thread. Right PITA to
stop it leaking it was as well. Had to resort to real hemp and boss
white to get a workable seal.

LS-X is your friend for this sort of thing.

--
*Being healthy is merely the slowest possible rate at which one can die.

Dave Plowman London SW
To e-mail, change noise into sound.

Dave Plowman (News) wrote:
In article ,
John Rumm wrote:
Got a feeling the most recent one I fitted did not have a washer, and
did seem to expect you to get a seal partly on the thread. Right PITA to
stop it leaking it was as well. Had to resort to real hemp and boss
white to get a workable seal.

LS-X is your friend for this sort of thing.

Yup, but I think my tube was so old it had set!

--
Cheers,

John.

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