Cooker Switch Melting Delonghi

[Diy592]

Hi,

Wondering if anyone can give me any advice.

I have replaced the Main Oven Selector switch on my Delonghi DFS 090 D0 three times and every 6 months or so it stops working and it’s melted.

The part of the switch that is melting is the bit that controls the main oven.

I keep thinking it’s the part that’s failing but this is the third one that’s melted.

The only thing I can think of and what I am looking for advice for is a while back the element was changed by a professional , if the element wattage was too high for the cooker would this cause the melting of the switch?

Thanks

 

[snowhead]

Have you changed the connector on the wire that fits on the switch?

It's most likely not making very good contact.

 

[Des 56]

I agree,its localised damage by the looks of it,no apparent overheating visible elsewhere
It probably needed that connection made good before the switch was replaced initially

 

[Diy592]

No I did not put on a new crimp, I have ordered a new one. Do you think that is all I need to do? All the connections seemed tight when I replaced the switch. Could a too high a wattage element cause this?

 

[westward10]

Can you show a pic of the connector.

 

[Diy592]

Thats the original. I changed this as a bit snaped off but the original did not melt.

 

[westward10]

Difficult to say if the connector is the problem, I assume it is the bottom right on terminal 1a but it likely to have suffered damage from the heat. Are you getting a complete new wire with the connectors fitted to both ends.

 

[Diy592]

No just the switch. I can put a new wire on though and try that.
The element was changed at the same time as the switch as this was thought to be the issue at first.

 

[westward10]

Is the picture of the original before you removed it because the crimp looks discoloured on that one also.

 

[Diy592]

Yes

 

[westward10]

What you ideally need is a new manufactured wire which links terminal 1a to the other.

 

[Des 56]

No I did not put on a new crimp, I have ordered a new one. Do you think that is all I need to do? All the connections seemed tight when I replaced the switch. Could a too high a wattage element cause this?

It looks as though your switch is rated 16 amp,the element for your oven 2.5 KW around 10/11 amp
As long as the element is not much over 3 KW it should handle the load

 

[SparkyChick]

The old and new switches are fundamentally different.

The new has the link between 3a and 4a, which the old one does not. 4a on the old is connected to 1a by the jumper wire... what was 3a connected to?

Is it possible that on the old switch, the piece that broke off (I'm assuming it was terminal 3a) was connected to something else. Now on the new switch it's connected to 1a instead, possibly bypassing some other switching resulting in an overload on 1a.

Just throwing that out there

That said, I agree with @westward10 , the crimp on 1a on the original does have a different colour to the rest, as does the copper visible through the crimp (compared tot he others). If you look at the base of that crimp there is also some fresh looking plastic, possibly where it has melted slightly.

 

[Diy592]

I connected the new switch up the same as the old. So new 3a has nothing connected?

 

[SparkyChick]

I connected the new switch up the same as the old. So new 3a has nothing connected?

But the new switch appears to have a spring link that connects 3a and 4a, so unless you've taken that off, it could be you're providing power to something that with the old switch was not connected.

I'm speculating because obviously it's tricky to establish what gets connected when from photos, but I think I'd be removing that spring clip that links 3a and 4a on the new switch before you try again.

 

[Diy592]

The pictures attached are of the new switch with it turned to oven.
Should I remove that spring clip do you think?

 

[Darkwood]

I'm under no doubt the crimp(s) are the cause of the repeating issue here, when you overheat metal it changes its properties and with crimps it makes them not fit for purpose, you need to try get hold of some pre-crimped wiring looms for the appliance, you will not have the correct crimps and/or crimper to do this kind of crimping, If you were to buy one it would cost you more than the appliance itself, you cannot cut corners on high current high duty connections like this (with regards to the CSA of the cable), I see it all the time with previous attempts with budget £30 crimpers causing the problem to reoccur.

 

[telectrix]

I'm under no doubt the crimp(s) are the cause of the repeating issue here, when you overheat metal it changes its properties and with crimps it makes them not fit for purpose, you need to try get hold of some pre-crimped wiring looms for the appliance, you will not have the correct crimps and/or crimper to do this kind of crimping, If you were to buy one it would cost you more than the appliance itself, you cannot cut corners on high current high duty connections like this (with regards to the CSA of the cable), I see it all the time with previous attempts with budget £30 crimpers causing the problem to reoccur.

agree, but i see it loads of times on factory fitted spade crimps. notably on catering equipment. must go to a certain pub at least once a month to fit new D/P switches and burnt 0ut crimps on carvery warmers.

 

[Darkwood]

I would say Tel its down to the quality of the factory provided crimps, after time the crimpers need calibrating or they can suffer mechanical drift and wearing down, as this is often massed produced in poorer countries with sweat shops making up the wiring looms then after a few years the quality of the final crimp suffers, it is also brand dependent, some are well aware of such issues keep on top of it with regular checks and calibrations.. add to that the quality of the crimps themselves that only have to be out by a fraction a mm and no matter how good the crimp is done the final connection will fail - spade connections speed things up in manufacturing but this is a downside of the process.

 

[Diy592]

Thanks for the advice, what about the on the new switch spring clip, should it go?

 

[jbjbjb]

I have EXACTLY the same problem as above! I have replaced my oven selector switch 3 times in the last year and the last one only lasted a month!, it has melted each time in exactly the same place as the previous post above, so it looks like I have to change the connector wire and the crimps attaching to the switch (again suggested above).
But my question is what sort of wire is needed and where would you buy the wire and crimps? Being a DIYer I’m not sure where to source these bits. I’ve got a new switch ready to go but no point replacing it without a new wire if this is part of the issue

 

[telectrix]

also check with manufacturer, see if there's a recall, seeing as 2 posters have both had the same problem.

 

[pc1966]

Probably your best bet for a replacement crimp is to use one of there that can be done with a normal insulated crimp tool:

https://uk.farnell.com/amp-te-connectivity/156667-1/receptacle-faston-r-a-awg22-18/dp/1772942

https://uk.farnell.com/amp-te-connectivity/156666-1/receptacle-faston-r-a-awg16-14/dp/1772941

The red one will work if your cable is 1mm CSA, or the blue one if 1.5mm, if unsure get a couple of each and check when you strip the wire, if it fits the red one use it, otherwise blue! Get a proper ratchet crimp tool if you don't already have one, something like:

https://uk.farnell.com/ck-tools/430021/crimping-plier-ratchet/dp/1283217

Or cheaper:

Error 410 | Screwfix

Thousands of products at low trade prices | FREE next day delivery available | 30 day money back guarantee on all orders.

www.screwfix.com

 

[jbjbjb]

That’s great! Many thanks! So will I be ok using the existing wire or should I replace this too?

 

[pc1966]

That’s great! Many thanks! So will I be ok using the existing wire or should I replace this too?

If the wire looks OK then just cut the old crimp off leaving as much conductor as possible, and crimp the new flag style terminal to it after stripping it carefully.
[automerge]1589626047[/automerge]
Let us know how you get on. As already mentioned, look for any recall info, etc, as it might have been a bad batch of switches or similar, but a push-on terminal that is not well connected can cause a fair amount of heat.

 

[jbjbjb]

Awesome, thanks again, hopefully this will be the last time I have to replace this switch!

 

[jbjbjb]

When I clipped the old spade connector off the wire it was obvious the wire was knackered, I clipped it back a bit more but the copper inside was still in bad shape. I got some heat resistant 3 core oven wire and took one of the wires out of this, and put the spade connectors on each end. Fitted the new switch and everything is working fine. Hopefully it lasts this time. Many thanks for your help