wiring immersion heater thermostat

Hi New here..
I've just replaced my immersion heater thermostat following a guide on the net - all quite easy, BUT..
the original (old) thermostat had only the live wire connected to it from the pole in the housing- and it worked that way I suppose - until it failed, but the water still got hot, and hotter etc.
I replaced it and wired the new one up the same way, live wire from the pole to the + on the thermostat, and it does not work - no light at the switch. so I connected the neutral pole to the - on the thermostat, and it tripped the circuit breaker.
confused - how does the thermostat interrupt the current anyway wired up like this? and why doesn't it work now??

The Neutral should go direct to the element post. The Line is wired in series with the stat and safety cut-out to the other element post. Don't forget the earth.

Thanks ricicle
I think that is how its wired up
live ( feed) to +ve post, and a short wire from same post to the thermostat.Netral in to N post, no wire out, leaving the N terminal inm the thermostat empty. but like this there is no light on at the switch. Clearly I'm doing something wrong..

JoeDugdale said:

I connected the neutral pole to the - on the thermostat, and it tripped the circuit breaker.

Click to expand...

Of course it would - a thermostat is a switch, only instead of making and breaking the circuit by you pressing a rocker like you do on a light switch it goes on and off according to the temperature.

By connecting live and neutral to it you would have created a short circuit, which is why the MCB tripped.

There's a very good chance that you've also destroyed the thermostat too.

This is really basic stuff, and the fact that you could make such a blunder shows that you know absolutely nothing about electricity, and how circuits work. I urge you to get an electrician to replace the thermostat and not do any more electrical DIY until you know more about it - doing things by following diagrams but not actually having a clue what or why you're doing is extremely inadvisable.

• //www.diynot.com/wiki/electrics
  
  
• //www.diynot.com/wiki/electrics:books
  
  
• http://web.archive.org/web/20080213151445/http://www.kevinboone.com/electricity.html
  
  
• http://web.archive.org/web/20080213151445/http://www.kevinboone.com/domesticinstallations.html
  
  
• //www.diynot.com/forums/viewtopic.php?t=7553[/list]
  
  
  

  confused - how does the thermostat interrupt the current anyway wired up like this? and why doesn't it work now??

  Click to expand...

  Wired like that it wouldn't, and it's probably broken now anyway.

Thanks. I feel properly chastised, and lucky not to have done more damage.

still not sure why there is a -ve terminal on the 'stat if it is not connected?

Forget all the +ve and -ve stuff. It just adds to the confusion. The mains supply is AC, it has Live or Line and Neutral.

The Live of the cable connects to one terminal of the thermostat, and nothing else.

The other terminal of the thermostat connects to one screw post of the heater element with a short wire link, and nothing else.

The Neutral lead of the cable connects to the other post of the heater element, and nothing else.

The Earth wire of the cable connects to the earth terminal of the immersion heater body.

many thanks this - and the previous links have been really helpful.