Wiring up an immersion switch

Fingers Mcginty

Hi, My old immersion switch had a high resistance and was heating up so I am replacing. I have a swutch similar to below



I'm going to wire it up as follows

Brown to Nout
Black into L1
Blue L2
Lout connected to COM with a short piece of wire.

I also have a 220V light that is outside the hotpress that was also wired up to the old switch so that when the immersion is on the 220V light would come on. I'm unsure how to wire it up to this new switch .....Help :eek:

Fingers Mcginty

I think I know but just want a second opinion....Do I kust connect the light across Nout and Lout?

.G.

Take a pic of the top of the immersion element and post it,and what's written on the front of the switch.Is at sink at the top and Bath at the bottom?

Its brown to Lin and Blue to Nin from your timer or fuseboard.Then join Lout to Com. after that it depends on the particular immersion group you have.

Usually it will be Brown from the flex to whichever of the L1 or L2 is the Bath,Black from the flex to whichever of L1 or L2 is the sink and Blue from the flex to Nout

Thats if you have a small tank with a combined bath and sink element.

Diggerdunne

It's not good practice to tap off the immersion circuit....

Bruthal

Just as superg says, the flex out to the immersions can vary in what colour was used for bath, sink, and neutral.

Take a pic of the top of immersion with cover removed will enable the neutral to be conformed, after that a multi meter can confirm bath and sink.

Or if you like, you can work them all out with a multi meter without removing the cover.

Measure resistance black to brown, black to blue and brown to blue.

Find the 2 colours that give 45 ohms or around that, this is both elements in series, so the other wire left in the flex in this test (besides earth) is the neutral.

Now test from this neutral to each wire that gave the 45 ohms, and the bath wire will give 17 ohms or so, the sink wire will be 26 ohms or so. Take note of them ad connect as superg described then.

Bruthal

Diggerdunne wrote: »

It's not good practice to tap off the immersion circuit....

Yea id agree with that, although if it was just a small indication light of some sort to show the immersion was on, it may not be too bad.

Fingers Mcginty

Diggerdunne wrote: »

It's not good practice to tap off the immersion circuit....

Duly noted...TBH I was surprised it was done in the first place. It's a mains bulb that is fed from the circuit. I'm thinking I'll leave it out of the circuit completely.

Fingers Mcginty

robbie7730 wrote: »

Yea id agree with that, although if it was just a small indication light of some sort to show the immersion was on, it may not be too bad.

HOw would you wire that light up Rob?

Bruthal

Fingers Mcginty wrote: »

HOw would you wire that light up Rob?

It would be from the Lout Nout of the immersion switch. The best thing would be a neon indicator of some sort that could be put outside the press, maybe even a fused spur with neon on it purely as indicator fitted into a dry lining box, supplied from these terminals. It would light whenever the immersion is on.

Its not usually done though, but it would stop people forgetting it has been left on maybe.

Diggerdunne

Good idea... Am I right in saying all new immersion switches are fitted outside the hot press as standard now???

beanie10

OMG dont connect it that way anyway. Blue to Nout, L1 & L2 is the bath and sink connection you will have to meter this out to find out which is which. Normally the black is the sink and the brown is the bath.

Diggerdunne

I think your not reading the full post. He asked about the neon light being connected up not the immersion....

Bruthal

Diggerdunne wrote: »

Good idea... Am I right in saying all new immersion switches are fitted outside the hot press as standard now???

Yes they are now, so that would be that sorted anyway as far as seeing they are on or off then.

Bruthal

beanie10 wrote: »

OMG dont connect it that way anyway. Blue to Nout, L1 & L2 is the bath and sink connection you will have to meter this out to find out which is which. Normally the black is the sink and the brown is the bath.

You might have to read the full thread before saying that, its not as if its very long. I was talking about wiring an indicator neon from the immersion switch to a position outside the hot press.

Also, not every immersion down the years had the blue in the flex as the neutral. And a clear description of how to identify bath, sink, and neutral is in post #5

As a matter of interest anyway, if you have brown, black, and blue, it would not matter what one is connected to the neutral and which 2 are connected to the L1 and L2 even though it wont work properly, nothing bad is going to happen. The immersion will just have one element working properly and when the other one is selected, both elements will be in series. Hardly the end of the world, although when switched into this series setup, the stat will be out of the circuit, which wouldnt be ideal.

Fingers Mcginty

Hats off to you Rob I'm wiring her up this mornin' ...will let yiz know how I get on

Bruthal

The blue in the flex should be the neutral anyway. Years ago i seen them with brown as neutral, and someone had the same question here a few weeks ago who took a photo of the immersion with cap off it and the brown was neutral in that too, but any in the last fair few years its blue, but i always either still test or visualy check anyway.

Under the cap anyway, the neutral in the flex goes to the stat on single stat ones and then out of the stst to the link that joins both elements.

On dual stat ones, the neutral in the flex goes straight to the link that joins both elements, so on any immersion the flex neutral ends up connected to the common link.

So like in post #5, blue to black and blue to brown will tell which element is bath and which is sink, once the blue is confirmed as neutral. And if blue is neutral,, if you measure resistance from brown to black, it will equal the readings of blue to black+blue to brown. So again, as in post #5, if you find black to brown is 45 ohms (for a 2kw sink, 3kw bath immersion), you know the one left, (blue) is neutral.

Assuming blue is neutral, measure blue-black, and blue brown and the lower reading is the bath. But which ever is neutral, the same applies.

beanie10

Diggerdunne wrote: »

I think your not reading the full post. He asked about the neon light being connected up not the immersion....

Sorry i was replying to the first post.The answer to where the light is connected is on the picture of the switch(on the back of the double pole side of the switch). Just trying to warn him before he connected brown to live out and blue to L2.

Bruthal

beanie10 wrote: »

Sorry i was replying to the first post.The answer to where the light is connected is on the picture of the switch(on the back of the double pole side of the switch). Just trying to warn him before he connected brown to live out and blue to L2.

Blue to L2 would not have any actual electrical problem, no short circuits or anything like that. All that happens is with the bath/sink in one position, one element will work properly, but switch the other way and it will have both elements in series, the consequences of which are the stat out of the circuit, and the heat output will be only 1.1kw. Draw out the diagram and try it.

Years ago some flexes had the blue as one of the lives, seems unbelievable, but we were reminded of it here a few weeks ago when someone put a pic up of one of them.

EDIT: Never noticed the little diagram of where to connect the indicator light myself:)

beanie10

Blue is neutral and should be connected to neutral connection and if it is old and blue is live its good practice to go back to the immersion and and rewire it to current colour codes.
I wouldnt be happy wiring up an immersion with the possibility of the stat being left out of the circuit, this is highly dangerous and ive seen the consequences of this first hand. With no stat the water boils up to the cold storage tank in attic which is plastic. The hot water puts the tank out of shape and spills over.
A couple went off for weekend and left immersion on, the stat failed on which caused the boiling water to over flow from storage tank down onto childs bed, luckily they werent there.

Bruthal

beanie10 wrote: »

Blue is neutral and should be connected to neutral connection and if it is old and blue is live its good practice to go back to the immersion and and rewire it to current colour codes.
I wouldnt be happy wiring up an immersion with the possibility of the stat being left out of the circuit, this is highly dangerous and ive seen the consequences of this first hand. With no stat the water boils up to the cold storage tank in attic which is plastic. The hot water puts the tank out of shape and spills over.
A couple went off for weekend and left immersion on, the stat failed on which caused the boiling water to over flow from storage tank down onto childs bed, luckily they werent there.

If they were there they would of likely known there was something seriously wrong long before that happened, it is very noisy in a house with a boiling cylinder. I have seen it myself also.


Anyway, no one here said to connect a neutral to L1 or L2.

Nor did i say the stat out of the circuit was good, it simply sounded like you thought there would be a short circuit when you said OMG dont connect like that. What was the OMG for? You realised the stat is out of circuit in one switched position? Or thought blue to L1 or L2 was a short circuit?

What we said was dont assume for certain blue is neutral on an immersion, if this is what you do, fair enough.

But the best practice is to check on any immersion to confirm blue is neutral. Thats what is being advised here.

EDIT: Actually you were replying to the OP when you said OMG, but still, no one here is advising bypassing the stat anywhere. Just showing the consequences of connecting a neutral to L1 or L2 is stat bypass with switch in one of either bath or sink position, which one depending on which the neutral in the flex was connected to.

Again, it would likely be noticed by the user, as in this position, the immersion would be extremely slow to heat, as 2 elements in series are only giving 1kw or so.

beanie10

If you read the original post where he is going to connect brown to Nout and blue to L2. Dont know about you but when someone says that alarm bells start ringing on my head. You dont know what will happen as a consequence, it could work, it could be slow to heat so he may leave it on all night. The best thing to do here is to open up the immersion and start from there.dont assume blue is L2. As stated the reason for changing the switch is cause the old switch is getting hot, maybe its connected wrong from the start. The way its connected to immersion needs to be investigated.

Bruthal

beanie10 wrote: »

If you read the original post where he is going to connect brown to Nout and blue to L2. Dont know about you but when someone says that alarm bells start ringing on my head.

No, alarm bells dont really ring, i just calmy tell them to confirm what is what. And thats what i and superg have done.

What did you believe happens when the neutral core is connected to L1?

You dont know what will happen as a consequence, it could work, it could be slow to heat so he may leave it on all night. The best thing to do here is to open up the immersion and start from there.dont assume blue is L2.

As already said, im assuming nothing, which is why i advised confirming what cores are what. The multimeter tests described in post #5 wont lie. In 10 seconds, all 3 cores can be positively identified beyond any doubt, unless 2 are connected to the same terminal in the immersion, which will also be shown within the same 10 seconds.

As stated the reason for changing the switch is cause the old switch is getting hot, maybe its connected wrong from the start. The way its connected to immersion needs to be investigated.

It has already been described how to confirm what core is what. Old immersion switches, particulary them old ones with the sticking out rockers, did tend to get noticeably warm anyway.

If the 3 cores were connected to 3 seperate terminals in the original switch, then there is no way the 3 of them could of been connected in any way to have a load higher than the 3kw bath element, and as described already, wrong connected neutral leads to one element working properly, and the other switch position has the 2 in series, so a lower kw than the small sink element. So 3kw is the max no matter gow they are connected, once 2 are not in the same switch terminal.

Fingers Mcginty

Did the resistance test from the immersion flex and identified what was what. Black = sink, Brown =Bath and blue =neutral ...Happy days. I have wired the bulb between Live in and Neutral out ...All working and I'm still alive. Thanks for all the help folks!

Bruthal

Fingers Mcginty wrote: »

Did the resistance test from the immersion flex and identified what was what. Black = sink, Brown =Bath and blue =neutral ...Happy days. I have wired the bulb between Live in and Neutral out ...All working and I'm still alive. Thanks for all the help folks!

The bulb should be between Live out and Neutral out if its for indication purposes. If from Live in then the bulb will have a live feed even with the immersion switch off.

Fingers Mcginty

That's the way it was wired in originally It's ok like this yeah? I mean the immersion is working with both elements and with the switch off the light is off too. I suppose it wouldn't be any hassle to rewire it to lout and nout.

M cebee

why don't you just relocate the switch outside HP

M cebee

if you have to do this -wire the lamp through a spur

Bruthal

M cebee wrote: »

if you have to do this -wire the lamp through a spur

My idea earlier was to use a spur with a neon as the actual indicator outside the press.

Bruthal

Fingers Mcginty wrote: »

That's the way it was wired in originally It's ok like this yeah? I mean the immersion is working with both elements and with the switch off the light is off too. I suppose it wouldn't be any hassle to rewire it to lout and nout.

No i would change it to the L out, it is only switching the neutral to the light, so it will go off, but it should also switch the Live too.

As M cebee says, a spur should be used out to the light. Although i would use a spur with neon as an actual indicator if it was me, if moving the immersion switch out was awkward.

seosamh

Hi,
This thread is very helpful and allowed me to use a multimeter for the first time. I discovered that brown is neutral for me.
Having wired the immersion switch, I am wondering about is how to wire the Timer (APT analog time clock). It has blue and brown coming from the fuse box and the blue and brown going onwards to the immersion switch. But how to wire it. It is not labelled with L1 etc.
Should the blues be together? Should the browns be alongside each other. There seems to be three empty slots the other side of each has a red and black, red, and red and black respectively.
The way I had it wired:
Slot 1 brown from fusebox
slot 2 brown going to immersion switch
slot 3 both blues
(earths were tied together)
Result: Light on switch always on (off, on and clock switch positions)

Thanks.

.G.

Post a photo of the connections if you can. there should be a label on it near the connections indicating what's what.Either way there is most likely L in for Brown from the fuse board,N In for blue from the fuse board,L out for brown out to the immersion switch and N out for Blue out to the immersion switch.

photo would help

seosamh

I don't have my camera at the moment but I did see the sticker on the side of the timer which indicated:
1 Live out
2 Live in
3 Neutal
E Earth

I connected it as above but did not connect the earth to the box as they were twisted together (from each wire)
The light of the timer box still lit up even though it was in the off position.
I noted that the wheel of the ESB meter was spinning faster which suggested the immersion was on. Also with a phase tester confirmed that current was getting to the 'Sink' terminal of the immersion switch.
Then I switched from Sink to Bath and that's when the burning smell happened. The timer started emitting smoke so I immediately turned it off at the fuebox.
The timer now is not responsive and I think will need replacing.
I wonder did I get something wrong in wiring the immersion box. The cylinder flex at the cylinder clearly showed the brown wire attached to a big N terminal and the ohm readings confirmed this as neutral.
Not sure where I have gone wrong, was the timer knackered anyway since it was showing on and was on despite being in the off position.
I will try get the camera in action.
Thanks.

seosamh

After the smoking incident I went and bought a new timer and I haven't looked back.And it has 15 minute interval pins which is an improvement.
Just wondering though, if there is a stat on my cyinder, where would that be. Can I use this to regulate the temp of the water as I am concerned not to supply too hot water to the pump (for sending water to the attic bathroom)s which only likes water not exceeding 60 degrees.

.G.

seosamh wrote: »

After the smoking incident I went and bought a new timer and I haven't looked back.And it has 15 minute interval pins which is an improvement.
Just wondering though, if there is a stat on my cyinder, where would that be. Can I use this to regulate the temp of the water as I am concerned not to supply too hot water to the pump (for sending water to the attic bathroom)s which only likes water not exceeding 60 degrees.

The stat is in the immersion group on your cylinder.If the brown wire coming from your immersion switch is neutral in your setup then that wire would be going into the stat in your immersion group.there will be a small dial on it for setting the temp.They are typically set to 60c already

seosamh

Thanks superg, very helpful
Can I bother you to ask a question about the neon indicator light as has been discussed above. I purchased a light with switch combination (rated 20amp) but also a fused neon light with no switch(rated 13 amp)
Since the switch is not needed I would prefer to use the 'light only' one but do I need to be concerned about its lower amp rating. Is it a rule of thumb that all immersion/central heating switches should be 20amp ir is that not relevant here in operating the light?
Also the use of the term 'spur' - does that refer to connecting the light wire Brown to Lout and Blue to Nout of the immersion switch?
Thanks

.G.

You still need the immersion switch in order to pick which element you want to come on when the timer powers it up.If you get rid of the the selector switch you would have to wire both the sink and the bath elements to come on together.This would typically mean a load of 5kw's which is way above what a 13 amp switch can handle.I would advise you to leave the immersion switch in situ,indeed its probably against the wiring regs not to have one.

Re reading above regarding your earth connection.A good connection on earth is every bit as essential as it is on Live and Neutral so even if they are twisted together you should terminate the pair in the earth connection provided on the switch

seosamh

sorry, I think I may have caused some confusion with my last post.

The set-up I was trying to describe involved:

the analog timer box,
the conventional sink/bath, ON/OFF box
and the neon light box

The neon light box came in two varieties: one with a simple light and the other with a light and a switch. I bought both.
Since I only need the light to indicate what is going on at the sink/bath box I don't need a controlling switch on the neon light box. What use could it possibly have?
The question then is over the amp rating of these boxes. is the Light only box sufficient at 13 amp or is the Light&switch box at 20 amps necessary.
Would 2.5 wire be sufficient, 3 core?
Thanks.

.G.

seosamh wrote: »

sorry, I think I may have caused some confusion with my last post.

The set-up I was trying to describe involved:

the analog timer box,
the conventional sink/bath, ON/OFF box
and the neon light box

The neon light box came in two varieties: one with a simple light and the other with a light and a switch. I bought both.
Since I only need the light to indicate what is going on at the sink/bath box I don't need a controlling switch on the neon light box. What use could it possibly have?
The question then is over the amp rating of these boxes. is the Light only box sufficient at 13 amp or is the Light&switch box at 20 amps necessary.
Would 2.5 wire be sufficient, 3 core?
Thanks.

You dont need the second switch or light at all,dont know why you have it.The Immersion switch should have a light on it as will the timer

the setup should be as follows.

Fuseboard feeds Timer,Timer feeds Immersion switch,Immersion switch feeds Immersion group

is your timer being fed from an existing circuit,eg sockets,and is this why you bought a spur?

It should have its own dedicated circuit

seosamh

The reason for this arrangement is because the immersion, timer, etc. are under the stairs and the idea of the light outside was to indicate whether the immersion is on or not without having to open the door and see. This could prevent leaving the immersion on inadvertently.
The immersion has its own line back to the fuse board.

.G.

I see.

If you wired it in the same size cable as the rest of the circuit then there shouldnt be a problem as long as its wired correctly.

I would wire the indicating neon in 2.5 sq cable direct from the output of the timer,ie L out and N out. When the timer switches on it will power the immersion switch and also the neon indicator

Bruthal

From the L out N out of the immersion on/off switch would be better, then the neon will only light when either element is actually on, i.e. when both timer and immersion switch are on.

.G.

robbie7730 wrote: »

From the L out N out of the immersion on/off switch would be better, then the neon will only light when either element is actually on, i.e. when both timer and immersion switch are on.

Indeed it would but since he almost had a fire earlier I reckoned it would be easier to steer clear and go out the timer:D

seosamh

Thanks guys, I think I will go with safety first and wire it from the timer. I'll let you know how I get on.

Bruthal

Well it will be an indicator to show the timer is on. If thats what you want, then well and good. But if simply connecting it to the timer instead of the switch, which would show the actual immersion is on is being avoided because the timer is deemed easier to connect to, then someone should be got in to do it.

How connecting it to the timer rather than the switch would be safer i am not sure. It seems only the safer option for a diy person, but in reality it is no safer that i can see anyway.

.G.

Not suggesting its a safer setup really.

I suggested the timer as easier cos there are less connection points on it so less places for him to wrongly put the cables into.On the immersion switch there are a lot more places he might end up putting the cables which may just confuse things hence why I suggested the timer.

For me and you there's no issue wring it from the switch,for the lad asking,there may or may not be,especially since the configuration of each switch can differ.

Seosamh,it is just as easy to do as Robbie suggest as long as you put the cable's in the terminals that he suggested and nowhere else