Neutral wire keeps melting - immersion heater

[Murdoch]

I think it might be because the electrician set the timings to auto so it only comes on for 4 hours a night - 1am - 5am. I could change this but I find it easier to just use the boost when I want really hot water 

4 hours is more than enough time to completely heat up an immersion tank ...... as for the burnt neutral, that’s odd to say the least.

 

[binky]

is it possible the neutral screw is cross-threded and not quite making proper contact? Or a poor pre-made connection on the heating element? 

 

[Sarahabarth]

No I don't have economy 7 - I just have a timer which is on economy 7 timings. That's how the guy set it up and I didn't want to change it because it made sense for it to heat up in the night. 

So the wires melted a couple of times and both times the electrician changed the thermostat. It was the brown wires that melted though. When it happened the second time the electrician recommended getting a timer at the same time instead of having to turn on every time I needed it. 

I had that fitted in December and since then the wires have melted twice and the water hasn't been as hot as what it used to be unless I use the boost. 

It's a flat and I just have electric. 

 

[Sarahabarth]

is it possible the neutral screw is cross-threded and not quite making proper contact? Or a poor pre-made connection on the heating element? 

From what I can see it doesn't look cross threaded but it is quite rusty. Also you can see the ends of the wires around the screw which I'm not sure if you are meant to 

 

[apprentice87]

Ok, immersion heaters.. I have changed many of these in my own house.. Often, the first sign, is not so much that the water does not get hot enough, it is more like there is not much of it..

When you get the immersion out of the tank, it is plain why, the thing corrodes and bursts open and therefore only part of the element down as far as the burst bit is working. So, you only get hot water down as far as the knackered bit. If you are one of those people that are incapable of running two taps at once, you would not notice this though.. You do not get electrocuted due to the bonding i presume!!

I have got decent electrics here now, so some time i will be in a position to tell you if the thing bursting trips RCD's [I rather suspect it might!!]

On an RCD related subject, you know the tumble driers that catch fire and burn your house down.. Well, i have got one!! Having had it to bits, i can tell you that it is a stupid design.. Where the fluff ends up can plainly be seen, BUT the damp fluff also shorts the elements to the pressed steel frame of the machine, so, if you have an RCD [as i have now] the first thing you know is that the drier will trip the thing. It is a wonder that the makers and/or insurers have not discovered this, and decided that the will not pay out as it is "not our fault your house electrics are faulty.." [Yes i know, but that is what they would say]

john..

 

[ProDave]

The other thing that happens in hard water areas is the bottom of the tank fills with scale. I have spooned half a bucket of scale out of the immersion heater hole before fitting the new one before now.

 

[Evans Electric]

I'm begining to wonder if the Imm/htr is a dual  element  one  and  the timed control is connected to the  short element .

Reading Apprentice's post ,   could it now have corroded  ?   I 've removed them  to find just two prongs of element  ...the bottom bit dropped off but still works with resistance of water  , (not very hot)   .    On a rewirable fuse  they'll keep working .  

 

[Sarahabarth]

I'm begining to wonder if the Imm/htr is a dual  element  one  and  the timed control is connected to the  short element .

Reading Apprentice's post ,   could it now have corroded  ?   I 've removed them  to find just two prongs of element  ...the bottom bit dropped off but still works with resistance of water  , (not very hot)   .    On a rewirable fuse  they'll keep working .  

It does have 2 elements. The boost is at the top and I only switch that on when I want really hot water. 

 

[Sharpend]

I suspect the element is scaled badly and not transmitting heat to the water. 

What you need is a ‘good’ electrician or a wise old plumber. 

 

[Sarahabarth]

I suspect the element is scaled badly and not transmitting heat to the water. 

What you need is a ‘good’ electrician or a wise old plumber. 

So do you think I'm better off getting a plumber to sort this or an electrician? 

 

[ProDave]

I usually change immersion heaters, unless the tank looks like it is on it's last legs.

I's a grey area. In an ideal world a plumber would change the element and an electrician would connect it. Do you trust an electrician to change the heater without damaging the tank? or do you trust a plumber to make a good electrical connection to the new heater.

The reality is some plumbers and some electricians can do both, but perhaps not all?

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