Hello, I really need the help of somebody who knows what goes on with kiln electrics, I am very quickly trying to learn so this is my first port of call.
Bought an electric kiln about 8 months ago, told it was 6kw single phase kiln (UK Power) Got a single phase 32A 240V isolator switch and wired it into the plug. Were a little confused as there were 5 wires coming out of the kiln but two were held together so wired them into the plug together. It has a brown and blue going to live, two blacks going to neutral and a yellow/green going to earth.
So yesterday I went in the studio to check on the firing and the program had finished but the kiln was not loosing any heat and there was a funny smell in the room. When I unplugged the kiln from the socket it started to drop. Whenever the kiln was turned on at the wall it would start to heat up again even without the programmer plugged in.
Once it had cooled I took off the outside to have a look and found one very burnt/charred relay. I spent a few hours researching and looking and this seems like it could be a common problem that the relays break. Scary that it breaks into the on position.
My problem is that I do not know if it was a fault in the relay or if the kiln is just wired completely wrong. I had drawn a basic circuit diagram of what happens when the power comes into the kiln but I still haven't working out if it is right. This kiln has been fired many times up to top temperature, what confused me was that the kiln has no transformer to change the power so it has 240V coming into the relays and the relay was rated at 20A 220V - ac so this just seems wrong but I don't know why. I dont know what happens when the power is split like it is so if somebody could make me any the wiser it would be much appreciated.
I don't want to go any further until I know what is happening with the electricity as this was quite a scare.
Attached my circuit diagram, sorry if it is incorrectly drawn but I have tried my best to just understand how the power flows round the kiln.
I have just noticed that in my drawing the top relay has the power flowing the other way and I just got my arrows the wrong way round. Ignore that.