Old immersion switches

[DamianB]

B5E0CAEB-54A2-476E-9132-3C20D9E11152

• DamianB
• 20 Jun 2018
• 1

Switch in kitchen

I have a switch in my kitchen above which is live and I suspect used to power the immersion and maybe a fan. This looks as if it feeds another switch in my airing cupboard which looks ancient.

7952ED32-C4D8-4E83-A533-1E598670DBC7

• DamianB
• 20 Jun 2018

Switch in airing cupboard

. Could anyone let me know if my assumptions here are correct.

I would like to update these and would appreciate some advice. Would it be a case of ripping both out and adding a new conventional switch in the airing cupboard ?

Many thanks

Damian

 

[stem]

The switch is for the immersion heater(s). The left switch is on / off. The centre switch is to select which one of two separate elements you wanted to use. One that heated just the top of the cylinder (sink) and the other that heated the whole cylinder (bath) the space on the far right was probably a neon indicator, so that you knew when the immersion heater was on.

The usual arrangement is to have the operator controls at a convenient place often remote from the heater such as in the kitchen, with an additional switch in the airing cupboard near the immersion heater that can be used to isolate it during maintenance. However, the isolator next to the cylinder is designed for industrial use, not domestic. You would normally have something rather more like the picture below. There is a flex outlet in the bottom for the immersion heater cable to connect to.

Something like this would be the replacement control switch:

Unfortunately, I can't tell from the photo if you still have dual heating elements or not. Sometimes they are combined in a single unit, sometimes they are separate. Often they are replaced with a single element, if so you won't need the sink / bath switch.

The wiring isn't visible either, so I would suggest that you get a professional in who will be able to check the cable is of the correct size, in good condition and that the overload protection and earthing are adequate.

 

[DamianB]

Thanks that is really helpful. I think this is a dual heating element. Industrial switch eh, doesn’t surprise me with this house. The thought of cranking that to on terrifies me.

Got an electrician coming to do the fuse box soonish so will arrange for an upgrade to my immersion wiring.

Many thanks

Damian

 

[stem]

It does look like something out of a Frankenstein movie, but it might not be particularly old or indeed dangerous. (if installed properly) They are still widely used. The design is robust because they would normally be found in industry where more mechanical protection is required.

A domestic immersion heater isolator would be rated at 230V, 20A. The industrial isolator could be suitable for a 3-Phase 400V supply connected to much heavier loads for example 160A They aren't cheap either, so maybe you could sell it, if it's in good working order.

 

[securespark]

It looks like there is only one butyl flex leaving the iso in the airing cupboard.

 

[JohnW2]

It looks like there is only one butyl flex leaving the iso in the airing cupboard.

It does. However, if you looked at a similar photo of my main hot water cylinder, you would see much the same, despite the fact that there are two immersions. The bloke who installed it all fed each immersion through its separate FCU (yes, I know, but i wasn't me!) - the one for the top immersion is in roughly the same position as the one in the photo, but the one for the bottom immersion is much lower down, well below what can be seen in that photo.

Kind Regards, John

 

[securespark]

I take your point about not being able to see the bottom of the cyl.
However, what if the iso switches both?
It looks like there are two cables coming in to the iso.

 

[JohnD]

I've had immersion heaters with a long and a short element under the same cap. I thought they had been discontinued years ago, but last time it was mentioned somebody found a supplier.

 

[stem]

You can still get them. There's an example here.

I would guess it likely will be a 'twin immersion' based on the use of the industrial 3 Phase isolator which would provide sufficient poles for isolating two heating elements, and the neutral.

 

[ban-all-sheds]

It looks like there is only one butyl flex leaving the iso in the airing cupboard.

How many cores does it have?

Looks quite fat to me.

 

[JohnD]

turning off the power, removing the cap and photographing the terminal connections, will tell us for sure.

 

[DamianB]

Here you go. Cap off, looks like a dual element.

Damian

 

[DamianB]

Two feeds into the isolator also...

 

[securespark]

Butyl is commonly 1.5 but I have seen 2.5, which is quite fat.

 

[Taylortwocities]

Here you go. Cap off, looks like a dual element.

Damian

Yes, two thermostats under the cap. So you have a dual element, with wiring to suit the remote control of either sink (partial tank heat) or bath (full tank heat) as well as an off/on switch.

Not sure if your assumption about this is correct though:

and maybe a fan