Zanussi combi oven/microwave tripping fuse

[Adsibob]

We have a Zanussi ZVENM7K1 combination microwave/grill/oven.

 

It was installed 3 years ago and we’ve been using it as a microwave oven for the last 2.5 years since we moved in. The max rating for the microwave is 1000W, and we have often used it at that setting.

 

Last night we used it in oven mode, perhaps for the first time ever (I’m not sure) and it tripped the fuse. Trying to turn it back on we get a fault FH24 and then FO17 before it trips the fuse again.

 

 Given the oven is rated at 3kw, if it is actually the case that we’ve never used it as an oven, is it possible the electrician who installed it only provided a fuse for a 1kw Microwave. I notice that both the nearby isolator switch and the fuse on the mains consumer unit are labelled “microwave” so maybe he thought it was just a microwave and not an oven as well.

 

If it is an installation error, is it straightforward to upgrade the fuses in the CU and in the isolator switch, or is the limiting factor going to be the type of cable used between the CU and the oven (which I estimate is about 12m to 15m long)?

 

 

[ProDave]

Have you looked up what those error codes mean?

 

Is it an MCB or RCD that trips? and does it only trip when the oven actually turns on?  Have you tried other oven modes, e.g fan oven, conventional oven, grill?

[MikeGrahamT21]

What is the current rating of the MCB in the fuse board for that circuit?

 

Youd need a 16A MCB for the 3kW device minimum but it all depends on cable thickness as to whether it will take it.

[Adsibob]

21 minutes ago, ProDave said:

Have you looked up what those error codes mean?

When I look them up, all I find is “for this error you need to call an engineer”, not very helpful.
 

21 minutes ago, ProDave said:

 

Is it an MCB or RCD that trips?

What’s the difference and how do I tell?
 

21 minutes ago, ProDave said:

 

and does it only trip when the oven actually turns on?  Have you tried other oven modes, e.g fan oven, conventional oven, 

 

it just trips when switched on - ie at the intermediate stage before actually selecting a mode.

[SteamyTea]

1 hour ago, Adsibob said:

“for this error you need to call an engineer”,

I would have thought a technician would be good enough.

 

1 hour ago, Adsibob said:

1 hour ago, ProDave said:

Is it an MCB or RCD that trips?

What’s the difference and how do I tell

A MCB is a modern fuse, a RCD is a safety device to stop electucution.

Sometimes they are combined.

Take a picture and post it up, someone is bound to know.

[Adsibob]

2 hours ago, SteamyTea said:

I would have thought a technician would be good enough.

 

A MCB is a modern fuse, a RCD is a safety device to stop electucution.

Sometimes they are combined.

Take a picture and post it up, someone is bound to know.

Here are two photos, one showing the whole CU and the other a close up. I’m concerned given the labelling that the sparky has wired it for a microwave and not for a combination oven:

[Adsibob]

This close up is in sharper focus k in case any of those font size 8 characters mean anything:

[ProDave]

That's an rcbo so there is no way to find out if it is tripping due to over current or earth leakage.

 

It's 16A it would have to be a very big oven for that not to be enough,

[Adsibob]

10 minutes ago, ProDave said:

It's 16A it would have to be a very big oven for that not to be enough,

Thanks @ProDave so is that sufficient to serve an oven that has a “total electricity loading” of 3000W?

[ProDave]

14 minutes ago, Adsibob said:

Thanks @ProDave so is that sufficient to serve an oven that has a “total electricity loading” of 3000W?

Yes the fault is with the oven.  Persevere searching for the meaning of those fault codes.  Is it still under any form of guarantee?

[Shan2010]

A year on almost to the day and I have the same issue.

 

did you get this resolved at all?

[Nickfromwales]

29 minutes ago, Shan2010 said:

A year on almost to the day and I have the same issue.

 

did you get this resolved at all?

On new appliances there is an oil coating sprayed onto the elements to prevent corrosion during transit /  storage etc.

 

With 2 BNIB ovens on one clients project, they reported trying to use them for the 1st time, each on their own 16/20a RCBO’s, and both ovens had tripped in the same (attempted) cooking session.

 

I went to investigate, as this was a brand new house where I’d done a full 3 phase electrical installation, so I assumed that the oil was the culprit or a contractor cockup; as 2 ovens on the same phase were popping at the same time it was mind boggling….

 

Turns out my initial suspicion was correct. I removed one oven, lifted the earth connection, and fired it up. Ran perfectly, stunk the room out for 15 mins, and then I reconnected the earth whilst it was heating and issue gone. 
 

Left it to cool down and reinstalled. Ran it again from cold, all good.
 

Same with the other one. Same results. 
 

Neff units, so not Howdens specials by Lamona, btw!

 

@Shan2010, is the unit on a moulded plug or made off to an oven switch (20a isolator like a light switch)?

 

See if lifting the earth (you need to be competent with electrics to attempt this!!) will resolve it and go from there, but only really relevant if the oven feature is being used for the first time. 

[Nickfromwales]

@Shan2010 is it an RCD, MCB, or RCBO that’s tripping? 
 

Show a pic of the offending item and post it up here if you’re not sure.