Neff U1721 Double circotherm Electric Oven - Answered Questions & Fixed issues

More likely the heater element.. I hope this helps...

There could be a fault in the lower oven , or it could be overloading the circuit. add the watts of the two elements and divide by line voltage, this will give amps , now check the fuse rating amps , it must be higher than the oven. If that checks out ok the fault is in the oven.

If you are sure there is 220v going to unit, it most likely is element or click / control. If you have a ohms meter, you can test the element

I think there is an inline fuse for each oven/element.

it sounds to me that the fan is not working properly. as the oven gets older the fans become weaker and then doesn't blow air over the element at a rate that can the temp down enough..

regards
Richard Saupe
http://www.saupe.co.uk
Oven Specialist

See if the toc is open circuit , it is situated just above the heater connectors at the rear .

https://www.dropbox.com/s/tw4yv3dvf56eje4/Neff-GB-1057-LHCS-OvenManual.pdf

Fire up the oven once in while that should solve the problem but remember your warranty.

As a licensed electrician I've dealt with similar situations many times before.
Your connections are getting bad (loose, carboned up and corroded) from the continual over loading and over heating. This causes more resistance and thus more voltage drop causing higher amperage. It's time to either replace the entire sub-assembly or the oven, it's just going to continue to get worse and will eventually cause damage to the bus in your breaker box.

Torx 20

Did you replace the element from inside the oven cavity? If so, you may have knock off one of the spade connections whilst pulling the bracket through. Isolate from mains, remove back panel behind oven (not in the cavity) and check you don't have a wire floating about. The wires usually look quite similar but if you look closing they should have a black or red fleck in them, the element has two prongs on each side, you need to put the two the same colour on one side and the other single different colour on the other prong. If the fan is working then you have not blown the limiter that you will see quite close to the fan, but you might have blown the thermostat or the selector switch. If the red light comes on the fascia when you select the temp then it's pretty safe to assume the thermostat is ok. Hope this helps

Turn off the mains power. wait about thirty secs. turn back on, you should have either all 0's or 8's flashing. Looking at the clock buttons left to right. press the button fourth from left and the - or + to set the time (doesn't have to be the correct time, just not flashing 0 or 8's). Leave for second until the display is not flashing.You should be able to use the oven now. If not you may have a problem with the clock, this can happen if you have been using the top grill with the door open and the controls have gotten too hot. Neff ovens have no function where the door is left open during cooking or grilling.

It sounds like the wrong replacement element for the power it is getting. If you are using a 220Volt stove, the element MUST be for that voltage and NOT for 110 Volts.

Having tried several ways to get the glass cover off, there is one other thing you can try.
Spray some WD40 around the glass cover,and keep trying to tighten and then unscrewng it, and tighten again.
If this does not work, then the last resort is to break the glass cover, which is what I have had to do in the past,. but make sure you can get a replacement cover first.
Please rate my solution.
Thanks.

To rtemove the nut, hold the fan blades,and at the same time undo the securing nut clockwise as though you were tightening it, as it is a left hand thread, and vice versa for tighteming it again
Please rate mhy solution.
Thankyou..

Isolate mains.Remove oven cavity back panel (4/6 phillips or 4/6 Torx 20 screws)Remove fan blade (reverse thread nut)....this is sometimes where you come unstuck, because the blade just won't budge.If that happens I normally then remove the back panel of the unit itself (doesn't need to come all the way off, I will usually leave the mains connections on and let it fall back as far as it will go safely...may have to loosen the cable clamp to get some slack on the mains)You will now see the other side if the fan motor.Remove the L and N (not pole sensitive so they can go on the new one either way).Remove the 3 Torx20 screws holding the fan in position. (some models have an extra spacer ring so be careful you don't lose them)Go back to the cavity and use something to give the motor shaft a whack to release the fan blade, bearing in mind that if it does budge the motor itself is going to fall out the back (stick an old towel etc to cushion the fall and protect the terminal block etc).The new fan usually comes with the blade attached, separate the parts, install the motor, attached electrical connection and then the fan blade, make sure its tight. At this point I would close up the back and just hold in place with one screw and test that the fan works. (don't forget that the oven will not operate when the clock is flashing, so set any time on the clock before selecting circotherm)If everything looks ok, get it back together and in housing and run upto 150 or 200 degrees as a last test.Good luck, let me know how you get on or if you need any further clarification. Please post the outcome as this will assist other users of the site looking for solutions to similar problems.All the Best.

Use the link http://www.neff-eshop.com/eshop/neff/gb/prodlg.htm?x=0&y=0&Maktx=Neff+U1721&eshoptype=Aenter the FULL enr from the rating plate, don't just pick the nearest one if the enr is U1721N0GB/75 that's the model you need to check as parts from one model to another can vary. This will open a diagramatic breakdown of the oven and you can search for the relevant part (and buy if online direct from Neff). Couple of things to remember, make sure you have the right oven (ie top or bottom) and whether it is the front or rear holder as one is like a keyhole and the other is a keyhole on its side.As this is a build under unit, it does make changing the part a little easier (depending on which one is broken, hoping for your sake that it's not the back top oven one..Argggh!!) You will need to get the oven out and I find it easier if it's on it's side with the faulty holder at the top. The side panel needs to come off (or at least be loose if it's a front holder) as the holders are held in place by a retaining clip behind the cavity wall, or if it is a screw in type, the screws comes in from behind the cavity wall. I suggest you order and get the parts first and this will give you an idea what you're dealing with. Let me know how you go and post any comments or problems you have whilst doing the repair (anything I've forgot to add) as this will help anyone else looking for a solution to a similar problem.Ps. If you are sensitive to fibreglass, wear a pair of gloves.

Bottom oven is directly linked to the clock, If the clock is on but not set ie 0:00 or 12:00 flashing it won't work, set the time (doesn't have to be right, just not flashing) try oven again. If this is not the problem please contact me again and we'll look further. Cheers

If when you select the temp on the control you are getting the red light to indicate the oven should be on the most likely problem will be the element. If it is the bottom oven element this is a crescent shaped element behind the back panel of the oven (panel usually held on by 4-6 Tx20 screws). The element is positioned around the fan blade and in some models (you have not supplied the complete ENr for me to check) there are 5 screws securing it in place. Two each side at the bottom of each end of the element and one top middle, this one may require the fan blade to be removed first to facilitate the removal of the screw and in turn the element (The fan blade is on a reverse thread nut). The electrical connections to the element are on the back of the left side end, so be very gentle when removing it so that the spade connectors do not come off (if they do you will need to get the whole unit out and remove the back panel to reconnect. DO NOT CARRY OUT ANY OF THE ABOVE UNTIL THE ISOLATED FROM MAINS...if in any doubt bite the bullet and arrange for a qualified engineer (such as BSH in the UK). Hope this gives you a starting point, if you require any further info or clarification,please add a comment and I will try to get back to you asap.Let me know how you get on.

use link http://www.neffcustomerservice.co.uk/bottom left click on 'instruction manual download' this will open new window...type U1721 in search box and click on any entry with II at the end this will download the installation instructions as a PDF file.Hope this helps