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John Smith
 
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Default Replacing electric water heater filament

John, thanks very much for taking the time to answer in detail.

My Mum passed away 2 weeks ago after 12 weeks in the local ICU and I am
pretty numb at the moment. The last thing I need now - although this is
nothing compared to the loss of my Mum obviously - is extra hassle of this
nature so your information is much appreciated.

Only this morning I was wondering whether I sell or stay but I think my Mum
is trying to tell me something - get a new immersion heater!

Thanks,


John.




"John Stumbles" wrote in message
news
On Sat, 11 Mar 2006 13:02:28 +0000, John Smith wrote:

Hi,

It looks like the filament in my electric water heater has gone - it must
be
20 to 25 years old. Electricity is getting to the switch but, for some
reason, this morning the water was cold and attempts to heat it up now
have
proved fruitless.


Could be the thermostat - worth checking - but more likely to be the
element.


Is this something I can change myself? I assume it is just a job of
unscrewing the filament - a tad rustry where it connects to the copper
boiler - and fitting a new one? Of course, ensuring the electrical supply
is
switched off when I do this?

Where can I buy one of these - B&Q or do I need to go somewhere special?
Is
filament the right word? Is there any specific size or power that I need
to
bear in mind?


Immersion heater is the word (and it goes in a 'hot water cylinder', not
'boiler'). You'll need the same length (usually 27" for top mounted,
11" for side-mounted). There's a grade more suitable for use in hard water
areas if you're in one. The element usually comes with a new thermostat
but if it doesn't buy a new one (of the right length) too as they now have
a separate safety cut-out in case the main thermostat fails to 'on'.
(Check that what you're buying has this separate cut-out just in case
there's old stock still kicking around.) B&Q and other sheds, real
plumbers merchants and electrical wholesalers and retailers should have
them.

I'dbuy a length of new cable too: the old one is liable to be in poor
condition due to heat and age. You want 2.5mm^2 heat-resistant cable and
this may be hard to find except in a proper sparks' merchants.

One last point - it looks like it needs a big wrench/spanner? Bigger
than any I have - is there a special kind I need? Can someone recommend
one?


Yes you'll need a suitable spanner: they tend to be pressed steel and
reasonably cheap. I've seen designs that are (a) flat (b) cranked and (c)
box-spanner with a flat handle off the side. The box and, to a lesser
extent, cranked types allow access when the element is recessed in a
cut-out in a foam-lagged cylinder, but if there's room to use a flat
type I'd get that. You'll need to remove the cable first to get the
spanner on. The immersion element nut will be well stuck on to the
cylinder: don't try to turn it smoothly but instead keep hitting the end
of the spanner moderately hard with a normal hammer until it starts to
shift. (This is why you want a flat spanner: it's a pain trying to do this
with an offset type.)

Clean up the surface off the cylinder boss before
fitting the new element. It may be easier to attach the (new) cable to the
terminals of the element before fitting it, but don't clamp it into the
cable clamp or you won't be able to get the spanner over it. The new
element should have a fibre washer to seal agains the boss but I usually
squish some Boss Green (not Boss White) on to help seal the join. Again,
tap it back using a hammer on the spanner.