Re: Boiler / Wiring - Emergency response needed from a spark etc

[Jim Noble <yahoo-groups@xxxxxxxxxxxxxxxxxx>]

On 28 Oct 2006, at 22:17, Chris Miles wrote:

> There is a small boiler unit in the kitchen.
>
> About 2ft wide, 2ft deep, 4ft high.
>
> There is a large copper tank in the cupboard at the top of the
> stairs. It has various bits and bobs such
> as drayton stuff... Is it a imersion(sic) tank? I am maybe just
> using the word boiler for this then.

Indeed, that is not a boiler. It's a hot water cylinder with an
immersion heater.

> I am concerned about the HW as well though as why the switched live
> is on the off terminal? Does it not matter?

It's very odd. The only thing I can think of is that power is only
sent to the immersion heater when the HW circuit is off. This would
stop you using both boiler heat and immersion heater at the same
time. HOWEVER,  I find it hard to believe you could route power to
the immersion heater through the programmer with it going pop or
burning your house down (it could be taking up to 3kW).

Is the hot water cylinder not heated by the boiler at all? How many
pipes are there connected to it? Do you have any sort of motorised
valves on the heating or hot water pipework?


> CH is not permanant live... It only becomes live when "Heating
> Advance" is pressed on.

As Nigel said, that might have been acceptable practise when old cast
iron boilers were being installed. These days the boiler will have a
permanent live because they run the pump for a bit after the heating
goes off.

Jim


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