I have replaced the main oven fan on a Smeg SP680MFA built-in oven which had blown and also the Safety Thermostat (190 degree) which looked blackened at the terminals.
On switching the new fan on, the connections at the new safety thermostat start to heat up within about 30 seconds, hot enough to start melting the insulation on the wires. The safety thermostat is connected directly to neutral.
I am wondering if this is another component at fault in the oven and may have been the cause of the original fan failure. Any thoughts or pointers would be appreciated.
Rgds
Don

Don, April 2010

Thanks for the reply Lincoln Appliance. I was slightly surprised but that's how the old safety thermostat was wired! All I did was remove the connectors from the old unit and connect them to the new one. I have an engineering background and always make notes, draw diagrams or even take photos before dismantling anything.
Anyway it's a bit academic now as I've decided to scrap the appliance and get a new one....definately not a Smeg product this time!
Thanks again for taking time to reply.
Rgds

Don, April 2010

Do not know enough about this oven to be completely helpful but the thermostat should not be connected directly to the neutral that is probably why it is melting. The thermostat should be wired so that power comes in one side then out the other side to a load, maybe a switch to an element or something similar. It's purpose in life is to cut the power off to the load if something goes wrong & the oven overheats.. Find a wiring diagram & follow it or get someone in to do it for you. Remember electricity can kill.

Lincoln Appliance NZ, April 2010