My Neff U1421 bottom oven has failed.

you need to check size of breaker the oven is wired too if this is to small it will trip also cable size

You need to replace the oven element.
This is located at the rear of the oven compartment, behind a removeable cover.

I have a u1421 with the same problem! I notice the fan doesnt run too well, sometimes it doesnt run at all, needs a prod to get it running. I suspect with no fan, that the element gets far too hot, and then starts to leak to earth, tripping the RCD. I'm gonna try buying a new fan motor - you should ckeck if your fan is running full speed OK.

You need to replace the oven fan element, as there is probably a seperate element in use when used on convection heat.
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Thanks.

The heating element is the likely culprit as they burn out and go open
circuit..(ie ...disconnected and will not heat up )
If you can use a multi-meter , then the element can be tested using the resistance range (with the oven SWITCHED OFF )

Can only be either element or thermostat. I suggest you check element and connections

Neff fan oven element video. 1, If the fan motor . in the back of the oven is going round and the temperature light is on (normally little red light), but there is no heat then you will probably need a new oven element, these are generally very easy to fit and readily available from our website these can be tested with a electric meter.
To gain access to the NEFF element .you will have to remove the back plate from inside the oven. Once removed you will see the fan and element,. if you look closely at the element .you will probably see a small hole burnt in it where it has blown. Sometimes however there is no evidence of a fault but the element is open circuit ie: broken inside the element casing, either way it will need replacing. Some elements will are fixed from inside the oven and some are held in place by nuts from the rear of the machine.
2, If your NEFF fan oven is getting warm but takes a very long time to cook or is burning the food more on one side than the other, then you need to check if your oven fan motor is working you will see the blade turning fast if it is ok. if the element is heating but the fan motor is not blowing the heat into the oven then you need To replace the oven fan motor is a little more expensive and a bit more involved.
3. If you have the opposite problem ie: your oven is over heating and burning everything then you will need to replace your NEFF oven thermostat
4, A quite common and easily overlooked answer is if your NEFF oven is not working at all ie: no heat and no fan then the chances are that someone has put the oven timer into AUTO mode, simply put oven back to MANUAL mode and all should be working again.


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It might be that the breaker is overloaded and it's no longer supporting the load of all the appliances together.If you do not want to change your breaker you can still use your oven by switching off other appliances that is running while you are using the oven

If you have an Ohm meter, then test anything you feel is failed. No sense in replacing good parts.

I am surprised that there is no wiring diagram somewhere on the unit, like in the control head, or on the top or back (most units built in the U.S. over the past 30 years have them. Don't know about UK, which is where I assume you are.).

Let me know! The overload on the back should have a red reset button. The thermal fuse has to be replaced if it's failed, and normally when it fails, the control head will not work. It usually does not carry enough current to power the elements.