Odd issue with Lamona electric oven.

[godlyk]

Hey,

Hopefully someone can help with or maybe have some advice on my oven.

I recently switched the oven on an left it to warm up, upon returning 10 minutes later I realised the fan isn’t running nor the oven light on however the thermostat light was out showing oven up-to temperature. I opened the oven door to find it was actually warm, so I changed the knob to the light setting to see if it would work. After this the light came on but then flickered and went out light a normal house-bulb would, however at the same time the main display on the oven started going on and off along with some sort of clicking noise, it then stopped and the display remained off.

I switched the oven off at the wall and left it for a few hours, I switched the oven back on and the same thing occurred with the main display it flicks on and off along with some form of click, maybe electrical components trying to switch? I opened the oven door and closed it and the same thing occurred.

I have took a video of the issue; https://streamable.com/l3balb

Hopefully someone has a idea.

[electrofix]

i would check there is power getting to the oven first

check the socket (if its plugged in )

check the oven terminal block

we need to be certain the unit is getting power before we look else where

Dave

[godlyk]

electrofix wrote:i would check there is power getting to the oven first

check the socket (if its plugged in )

check the oven terminal block

we need to be certain the unit is getting power before we look else where

Dave

Socket is working fine with a kettle.

I need to check the terminal block in the morning.

I think the unit gets power, If I do the door slam like in the video with the plug socket switched Off then the display doesn’t flash up like it does when the socket is On.

[electrofix]

was trying to figure from your vid if the display flashes at a regular rate without slamming door. Power in all ovens goes straight to the clock as the clok is powered 24/7. There may be a thermal cutout but all in all cannot be any of the switches

Dave

[godlyk]

So I took the oven out and did some deeper investigation.

I found burnt connectors on the back of the grill element. 1 blue wire is disconnected from the connector.
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I have tested components within the oven with a multimeter;
Cut-Outs reads 0.3 ohms.
Oven element reads 28 ohms.

Grill element is acting very strange, I cant get a good reading when I use the prongs I saw many different readings including some in million ohms…, however with the croc clips it reads 21 ohms.

So I know this might seem dangerous, however I switched the socket back on, and touched the blue wire onto the prong it had broke off, I can see the wire arcs but if held on the connector the oven returns to normal and powers back on.

I have established the harness is damaged, can I repair this, is it even safe to repair? I have soldering skills and would have no issues replacing the connectors. I’m just unsure if the grill element is broken or not what with the inconsistent readings I got. Is it the element thats broken causing resistance which has made the wires burn out?

[electrofix]

one of the problems with connections when they get into this state is you have to try and get a good connection otherwise it will just burn out again.

you can repair the loom but you need to cut the wores back to clean cable. if its oxidised it wont get a good connection and burn out. but at least with the cable you could solder the connections as well to help

chances are you need a new element and connectors and it will be well

if your not worried how long it will last you can clean element connectors and replace terminals and then use it and see. you have to make sure terminals fit tightly but the terminal will now be bare steel; which will rust over time

Dave

[godlyk]

Dave Id just like to thank you for taking your time in order to try and help.

Ok cool, so I will think about how I can repair the harness, the wire is oxidised and will need 1-2 inch cutting off, I have a couple of reels of copper cable knocking about so I can extend these and heat-shrink back over the solder joins, do I match the wire rating or be better is this ok?

I spoke to a friend who repairs washing machines and He thought the same as you say in regards to needing a new element so thats been ordered.

I’m more worried about fire to be honest, I have to live with this thing under my bedroom, I want it in a safe state so these damaged connectors and wires have to go. Could you maybe help me understand a few things;
Why does the oven present the same symptoms when the grill element is unplugged, is it also because of the damage to the wiring loom?
To add to the question above, when I separate the 2 blue wires the oven is just lifeless.

I have a Insulation meter so I am able to test the oven in depth, So I decided todo some insulation tests on it; however I don’t really understand what Im doing here, I was directed by my friend. All cabling is presenting 2.0 megohm insulation results until the point of when I connect those 2 blue wires.

[electrofix]

chances are the neutral supply to the clock goes through the element. it makes sense as it reduces the length of the cable carrying higher currents. Its unlikley to go on fire, you have more chances of your washer or tumble dryer doing that. for a fire to happen you need 3 things heat, fuel and oxygen. In a cooker the supply of fuel is limited unless something that cooking catches fire so when its not in use its highly unlikely.
The cable you need to use must be a simlar cross section or better

dave

[godlyk]

Ok, I see the Neutral path from the socket goes nowhere into the oven so that makes sense.

2 of the damaged wires are 16awg 150C 300v, could I replace these with 18awg 105C 600v?

[electrofix]

would be good to get something that will carry the heat more unless, your going to sleeve it with a heat resisting material. voltage is fine as long as the current capacity it equal or better

Dave

[godlyk]

I managed to get the crimped connectors off the cables, cut out the damage, put the connectors back on the wires, cut a zip-tie so cables would reach and did a megger test on the oven and all came back ok.
Plugged it in and its all back to normal and working fine.
Is it safe to say the grill element maybe faulty which has causes resistance and melted those wires?

[electrofix]

its not the grill element as such its the connections. if the connections are clean and tight it will be fine.

clean well made terminals dont cause problems as they age resistance increases in the joint and resistance is heat

Dave

[godlyk]

So its a case of the terminals are old and have built up resistance which has caused them to melt?
Why has it happened to the terminals of the grill element as opposed to the oven element for instance, Im sure both the connections was very clean and well made when the oven was manufactured.

[electrofix]

grill element terminals get hotter. grill is 2000w oven is 1800w but has a fan so does not get as hot

and yes heat degrades the terminals

Dave

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