"Michael Chare" wrote in message
...
"MrCheerful" wrote in message
...

"NC" wrote in message
news:xKU4c.434$sg7.202@newsfe1-win...
MrCheerful wrote:
"NC" wrote in message
news:3JT4c.187$N1.178@newsfe1-win...

All,
I am on Domestic 10 elec and so my immersion tank heats the water
overnight. Yesterday I noticed that the water was cold after only a
small amount had been used, I checked the fuses etc and evrything
seemed
OK. So, I put it down to using a little more than we thought and
hoped
it would be hot again this morning - its not !
So, how do I go about testing the element to see if its dead ?? I am
competant with a DMM but what I am wondering is how these things
normally show they are dead - will earth short to neutral / live,
will
the live/neutral resistance go up to infinity ?? If I can do this
simple
test myself I can call my electrician I *know* whats wrong rather
than
ask him out it tun out to be something else (like what ?!?!).

Thanks in advance,
N.


Elements are very cheap and fail regularly in hard water areas. If
live
was
shorted to earth the fuse would blow. Quite often a small amount of
current
will flow through the element, so a resistance test will only help
if
you
first work out what the resistance should be, in your case you are
looking
for about twenty ohms across the element. If your figure is a long
way
up
from this, then the element has failed. Turn the water off,
disconnect
wiring, unscrew and reverse the process to install a new one. Often
not
as
easy as it sounds.

MrCheerful



Thanks - confirms my thoughts - l/n resistance is in the region of
Mega/Kilo ohms! Just my luck - rented a flat in the same block for a
year - element went in there. Now bought this one and its happened
again. Block is about 3/4 years old so just about expected lifetime as
its very hard water - just my luck to catch them both !

Some immersion heaters are specifically designed for hard (aggressive?)
water:
See http://www.bes.ltd.uk/nav_graf/frames_cat.htm


Well the one we just fitted was a Backer all singing all dancing stainless
steel sheathed jobby[1], which ought to last a fair while, but i bet it
doesn't. (water is v hard- blame 7 trent)

[1] = £££££

Tim..