On 08/02/2012 15:08, Adam Funk wrote:
> I need to replace the immersion heater in a traditional hot-water
> cylinder (with a cister and a coil heated by the boiler). The
> existing model is labelled "HEATRAE GOLD DOT / 2.3--3 kW / 210--240 V
> AC ONLY / LENGTH 27" FIXING V". (The element was installed at least
> 17 years ago.)
>
> I see from googling that the Heatrae Gold Dot product in 27" size
> still exists. Can I buy one, safe in the knowledge that the thread
> will be the same? (In other words, I won't get a nasty surprise when
> I've drained the hot water& unscrewed the old element,& am about to
> try putting the one in. I'd really prefer not to have to leave
> everything hanging open while I cart the old element to a shop for
> comparison.)
>
> Also, are there any tricks for getting the water level in the cylinder
> below the fitting for the element? Or do I just shut off the water to
> the cistern, run as much water out of the hot system as I can, and
> then mop up what runs out when I unscrew the old element?
>
> Thanks,
> Adam
AFAIK the thread hasn't changed in a very long time. The problem with
draining is that the DHW supply normally comes from the top with the
cold feed to the bottom. Not usually much spillage with a top entry
element; you *do* have a wet and dry vacuum cleaner, don't you? If the
element is side entry at the bottom, you need to hope your plumber
fitted a drain cock on the cold feed.