I need to fix a failed immersion heater in my hot water cylinder;
which seems in principle straightforward enough. The problem
is there seems to be no way of draining water out of the cylinder
without removing one of the elements! There are two heaters,
both side mounted one about a third of the way down, the other
at the bottom.

There is a "bolt" just below the top element, which might be where
a drain tap of similar should have been fitted, but I don't actually
know what it's for (if anything).

The hot water is drawn from the top of the cylinder, cold goes
in at the bottom; so shutting the inflow and opening the hot
taps has minimal effect on the amount of water in the cylinder.

It looks like I'll just have to take out the top element and try
to catch as much as possible in a bucket. Unfortunately, it's
at least several buckets worth, and it's going to gush out when
I remove the element -- and I'm not sure the flat downstairs needs
an in-house waterfall.

So this all sounds pretty impossible to do with any degree of
dryness. Any one got any suggestions or miracles that might
work better than a lot of towels and a hopeful waving of buckets?

Thanks,
#Paul

wrote in message
...

I need to fix a failed immersion heater in my hot water cylinder;
which seems in principle straightforward enough. The problem
is there seems to be no way of draining water out of the cylinder
without removing one of the elements! There are two heaters,
both side mounted one about a third of the way down, the other
at the bottom.

There is a "bolt" just below the top element, which might be where
a drain tap of similar should have been fitted, but I don't actually
know what it's for (if anything).

The hot water is drawn from the top of the cylinder, cold goes
in at the bottom; so shutting the inflow and opening the hot
taps has minimal effect on the amount of water in the cylinder.

It looks like I'll just have to take out the top element and try
to catch as much as possible in a bucket. Unfortunately, it's
at least several buckets worth, and it's going to gush out when
I remove the element -- and I'm not sure the flat downstairs needs
an in-house waterfall.

So this all sounds pretty impossible to do with any degree of
dryness. Any one got any suggestions or miracles that might
work better than a lot of towels and a hopeful waving of buckets?

Thanks,
#Paul

Get a pro with a pipe freezing kit to put a drain cock in the water inlet.

Turn off the water further away and let the water syphon out of the tank via
the inlet.

Disconnect the inlet and let it drain from there.

Remove the outlet pipe after draining as much as possible and use a hose to
syphon out the tank.

MrCheerful

On Thu, 1 Jan 2004 18:36:24 +0000,
wrote:


I need to fix a failed immersion heater in my hot water cylinder;
which seems in principle straightforward enough. The problem
is there seems to be no way of draining water out of the cylinder
without removing one of the elements! There are two heaters,
both side mounted one about a third of the way down, the other
at the bottom.

There is a "bolt" just below the top element, which might be where
a drain tap of similar should have been fitted, but I don't actually
know what it's for (if anything).

The hot water is drawn from the top of the cylinder, cold goes
in at the bottom; so shutting the inflow and opening the hot
taps has minimal effect on the amount of water in the cylinder.


Shut off the cold supply and open a tank fed cold tap below the level
of the cylinder if you have one.
Otherwise disconnect one of the top connections after draining as far
as possible, then insert a length of hose and syphon.

--
Niall

On Thu, 01 Jan 2004 18:36:24 +0000, kinsler wrote:


I need to fix a failed immersion heater in my hot water cylinder;
which seems in principle straightforward enough. The problem
is there seems to be no way of draining water out of the cylinder
without removing one of the elements! There are two heaters,
both side mounted one about a third of the way down, the other
at the bottom.

There is a "bolt" just below the top element, which might be where
a drain tap of similar should have been fitted, but I don't actually
know what it's for (if anything).

The hot water is drawn from the top of the cylinder, cold goes
in at the bottom; so shutting the inflow and opening the hot
taps has minimal effect on the amount of water in the cylinder.

It looks like I'll just have to take out the top element and try
to catch as much as possible in a bucket. Unfortunately, it's
at least several buckets worth, and it's going to gush out when
I remove the element -- and I'm not sure the flat downstairs needs
an in-house waterfall.

So this all sounds pretty impossible to do with any degree of
dryness. Any one got any suggestions or miracles that might
work better than a lot of towels and a hopeful waving of buckets?


Look around at the pipework on the inlet into the bottom of the HW cylinder
(HWC).
There may be
a) a drain point (attach hose expect the drain point to dribble a lot).
b) a valve at low level: possible to close it off, drain _roof_ tank (using cold
water) and then open the non HWC side pipework and use the valve to control
the emptying of the cylinder messy but possible.
c) with the inlet off you can drian to the top of the cylinder level.
you then open the pipework at the top of the cylinder (might not be
easy) and put a hose from the top into the cylinder to syphon off the HW.
When completely empty you can work on both immersions.
Also add a tee and a drain point or 1/4 turn service valve for future use.

HTH



--
Ed Sirett - Property maintainer and registered gas fitter.
The FAQ for uk.diy is at www.diyfaq.org.uk
Gas fitting FAQ http://www.makewrite.demon.co.uk/GasFitting.html
Sealed CH FAQ http://www.makewrite.demon.co.uk/SealedCH.html

In an earlier contribution to this discussion,
wrote:

I need to fix a failed immersion heater in my hot water cylinder;
which seems in principle straightforward enough. The problem
is there seems to be no way of draining water out of the cylinder
without removing one of the elements! There are two heaters,
both side mounted one about a third of the way down, the other
at the bottom.

There is a "bolt" just below the top element, which might be where
a drain tap of similar should have been fitted, but I don't actually
know what it's for (if anything).

The hot water is drawn from the top of the cylinder, cold goes
in at the bottom; so shutting the inflow and opening the hot
taps has minimal effect on the amount of water in the cylinder.

It looks like I'll just have to take out the top element and try
to catch as much as possible in a bucket. Unfortunately, it's
at least several buckets worth, and it's going to gush out when
I remove the element -- and I'm not sure the flat downstairs needs
an in-house waterfall.

So this all sounds pretty impossible to do with any degree of
dryness. Any one got any suggestions or miracles that might
work better than a lot of towels and a hopeful waving of buckets?

Thanks,
#Paul


My hot cylinder has a drain tap at the bottom of the cold feed pipe - just
before it goes into the bottom of the cylinder. What size is your cold feed
pipe, and can you get at it? I'm wondering whether you could fit a tap in
it, using the sort of clamp-on and pierce fitting ** somtimes used for
outside taps and washing machine supplies. That would, at least, allow you
to drain it in a controlled fashion. If you don't fancy that as a long term
solution (not sure I would!) once the cylinder is drained, you can remove
the temporary tap, cut out the pierced section of feed pipe and fit a proper
drain tap for future use.

** Not sure I've ever seen these in anything other than 15mm - so if your
feed pipe is 22mm (which it likely is) this may not be possible. Anyone seen
any of these things for 22mm pipes?
--
Cheers,
Set Square
______
Please reply to newsgroup. Reply address is Black Hole!

Ed Sirett wrote:
a) a drain point [...]

Now I look at the tank again, there's actually a a small
tap just below the bottom element -- I hadn't noticed it
before because it's so close to the floor. So I just need
to get myself a bit of hose to wedge onto it.

And many thanks to everyone for all the replies.

#Paul

In an earlier contribution to this discussion,
wrote:

Ed Sirett wrote:
a) a drain point [...]

Now I look at the tank again, there's actually a a small
tap just below the bottom element -- I hadn't noticed it
before because it's so close to the floor. So I just need
to get myself a bit of hose to wedge onto it.

And many thanks to everyone for all the replies.

#Paul


One final tip. Loosen (but don't remove!) the old immersion heater *before*
you drain the cylinder. It will be *much* easier with the weight of water
keeping the cylinder still. It will probably require a *lot* of shifting -
maybe by sliding a metal tube over the handle of your immersion spanner to
get greater leverage.
--
Cheers,
Set Square
______
Please reply to newsgroup. Reply address is Black Hole!

One final tip. Loosen (but don't remove!) the old immersion heater
*before* you drain the cylinder.

Yes, and be aware that failure is quite common. You should have a
contingency plan to replace the cylinder. If you could benefit from a
different system, such as a heat bank etc. then consider this now, so you
don't just replace like with like in a panic when an upgrade could be
beneficial.

Also, ensure that the water supply is shut off and the hose connected when
starting to loosen the immersion. If the cylinder splits, you can then, at
least, start draining down the cylinder rather than waiting for the entire
contents to spill out.

Christian.

On Fri, 2 Jan 2004 13:07:20 -0000, "Christian McArdle"
wrote:

One final tip. Loosen (but don't remove!) the old immersion heater
*before* you drain the cylinder.

Yes, and be aware that failure is quite common. You should have a
contingency plan to replace the cylinder. If you could benefit from a
different system, such as a heat bank etc. then consider this now, so you
don't just replace like with like in a panic when an upgrade could be
beneficial.


Yep. Last one I had a hand in taking out, when it finally shifted the
thread insert in the cylinder cracked, and the replacement wouldn't
seal.

--
Niall