Bosch Wall Oven HMD8331 issues

We purchased an apartment new 4 years ago. Used as holiday until 12 months ago, this Oven has never worked properly it gets to 150 degrees and throws the switch! I have bought an Air Fryer & a Convention oven and use those. BUT it is time to find out if anyone else has this problem. I am having a problem finding a Bosch appliance website! Hope someone can help.

At 4 years I recommend you read about your rights under the Australian Consumer Law if you have not already, and try to deal with the retailer who sold the oven, if known, as they would be responsible. It is an interesting situation if the builder is effectively the retailer and would thus own the problem.

Sometimes a company will step up, and throwing ‘the switch’ (breaker?) at 150C is clearly a fault. If the retailer is unknown in this context put that to Bosch as to why you are asking them to ‘fix the fault’. Your new (I take that as new construction, not just new to yourself?) apartment purchase should be sufficient as a proof of purchase.

Please let us know how you go.


It is very interesting as it may not be the builder, but possibly the electrician who installed the oven when the house was built 4 years ago. Unfortunately statutory warranties aren’t transferrable to another party…but, if you have proof of purchase from the builder/electrician (they gave you the receipt from the retailer they purchased it from), then you may be able to exercise your consumer guarantee rights under the ACL. This is providing the receipt doesn’t have any buyer details (such as XYZ Electrical P/L) as a retailer could ask proof that you are XYZ Electrical P/L.

If you don’t have proof of purchase from the retailer, it will be impossible to take it further as you need such to make a warranty claim.

Also, you possibly should have followed up your rights soon after you moved into your house as the oven would have still been under the manufacturer warranty and easier to make a claim…after the manufacturer warranty when one tries to exercise their consumer guarantee rights, there is often argy-bargy between the parties to try and get some sort of resolution, it any.

1 Like

Bosch Australia Contact Number is +61 3 9541 5555

The Builder should still be responsible under their contract obligations for faults in the Apartment as it is only 4 years old or thereabouts. As the oven is a fixed appliance this should be their responsibility, if this is Strata title then the Management should be able to give you those Builder details.

Knowing which State also may help point you in the right direction regarding claims eg SA has 5 years in which a claim can be made for faults and 10 years for defective work. So under SA rules if it was bad wiring then it would be considered defective work and has 10 years of coverage, if a faulty oven then 5 years as they as part of the build “be made of good and suitable materials”.

1 Like

How old was the oven when you bought the property?

What do you mean by ‘throws the switch’? Do you mean the thermostat stops heating so that 150 is the maximum temperature the oven reaches or do you mean it trips the circuit breaker?

1 Like

Thank you very much. I got onto the contact you sent me, (not surprising) he said could send a tech out at $100 per hour. It would probably take 100-200 for the call. I will wait to see my husband and possible at that rate get a local tech to look or chuck it out & buy a different brand! Our Bosch Microwave (same age & use) kept turning on, luckily we were here, we got rid of it and purchased LG Convention/Microwave - works well and is used a lot. These apartments all have the same Microwave Ovens and quite a few have had to be replaced. Not a good ad for Bosch.


Thank you grahroll, unfortunately the Developer/Builder went broke! See my previous answer.


It trips the circuit breaker. It has the correct Wattage? on the switch. The oven was new when we purchased the property as it was the last one to sell and had not been lived in. The property is about 10 years old now. I am waiting on my husband to make a decision on what to do. If we replace will be looking at Choice to see which would be the best :slight_smile:

1 Like

If ovens aren’t used for a while or excess water is placed on the element during cleaning, the elements can absorb water and when the reach a certain temperature can short out triggering the earth leakage circuit breaker.

There are two options if this is the case, try and dry out the element someway or to replace the element. Most modern ovens have multiple elements (bottom, top, fan forced) and one or more could be the problem.

So the oven will be 10 years old…and any consumer guarantees are likely to have passed. An oven sitting for 6 years, the above could be the problem. If it was the problem, it is unlikely to be covered by a consumer guarantee or warranty as the problem has been caused by the consumer…that being no use if the oven to maintain its elements.


The Building Insurance for the Building still may be able to be used (they would have had to have it for when the Apartment was constructed), this may require contact with the Building Construction Authority for your State/Territory about how to access it. It may allow you to at least seek reimbursement of any costs you have had/will have to outlay to rectify the fault.

Between 1 Jul 2009 & 27 Oct 2016

After 28 Oct 2016

Or there may be Professional Indemnity Insurance cover the builder had at the time of Construction (almost mandatory)

1 Like

Thank you so much phb. This just might be the problem, we are in Queensland and it gets humid. I will go about drying it out several ways including keep turning it on & putting on the DRY cycle in the aircon overnight. Will keep doing this until we (hopefully) get it to work. The tech I spoke too didn’t think of that & I let him know that it was used Very little in our 1st 3 years here! Mostly because it didn’t work!!! I will let you know in a week if any improvement.


The circuit breakers are usually rated by the nominal circuit capacity in Amps (current). EG 16A, 20A, 25A There is a second rating for the maximum short circuit current the breaker is designed for 6kA or 10kA. You will need this detail if you are looking to replace to ensure the replacement oven is within the capacity of the circuit provided.

At 10 years old there is a possibility the type of breaker installed has integrated RCD (earth leakage protection). This can also trip the breaker as the oven heats up. There will be a small button for trip testing these types of circuit breakers.

It would be prudent to have an electrician check the circuit. It’s also not unknown for circuit breakers to be faulty, develop faults with age. (1 in 100 to 1 in 500)
As most wall ovens are hard wired, removal and installation of a new wall oven will require an electrician. Note not all wall ovens are the same size. Hopefully you have a copy of the install manual for the old oven. It will have the relevant dimensions, just to be 100% sure.


This won’t be enough to dry it out. It needs to be removed and heated to 110°C+ (say in another oven) for a while to evaporate the water out. We have had success with a breadmaker using a hair dryer on the element for about an hour …as it had absorbed water and tripped a breaker… but this may be impractical in an oven as the elements are often covered and covers removed to gain access.

This website provides remedies for such problems…


Usually the oven heating up to 150C should be enough given the residual heat. If that is how I read the fault details. There are a multitude of alternate possibilities that are not a moisture related coil fault. Especially if it is tripping the main breaker by over current.

Moisture would most commonly cause the same breaker to trip if it is an RCBO type, IE an RCD trip due to insulation failure, or through current leakage. Hence the previous question on the type of breaker.

The oven heating coils are hard wired into the oven. Not something that is for the home handy person to be contemplating. There are other electrical items in the oven that may be the cause, and not the electric resistance heating coils.

While it may sound very simple, it is suggestive of many other possibly serious faults. Professional repair person and Electrician territory.


Thanks all you people. I will still give it ago until my husband gets here. Will leave it heating until it stops and hopefully turn the heat up each time I can get it too work. Left it at that, I appreciate all your help. Marvelous.


I thought that was the case with the bread machine…it would heat up and when it gets to a certain temp (element too hot to touch), would trigger the breaker. We cycled heating until the breaker triggered about a dozen times to no avail. From reading about it online, it needs at least an hour over 110oC (higher temperature is better) to evaporate out the water…otherwise when it heats and shorts…the water stays within the element.


I’m familiar with industrial heating elements and understand the issue, as well as the potential solution. I’ve installed tested and commissioned same. There is zero evidence that is the fault. It’s a guess. It might be a good guess. It could also be wrong. I worry about the second outcome.

Assuming the problem with the oven is due to moisture absorbed into the insulating powder in the heater elements, it’s not something for safety reasons the average home owner to start mucking around with. It’s why I’d not offer advice on home remedies in this instance.

As outsiders we do not know why the oven circuit breaker is tripping. Is it tripping on earth leakage (ground circuit fault in Americano) or is it tripping on over current? Assuming it is earth leakage protection, it could be many different things, including a faulty Circuit Breaker, or some other item on the oven that is temperature or time sensitive.

An electrician can test for all the different likely faults, test the heater elements, and if they are faulty remove them for replacement or drying out if that is appropriate. Importantly over ten years the owner has not been first hand with the property until the more recent 4. Do any of us know reliably what has happened with the oven?

We are also assuming the oven is on a circuit that has earth leakage protection and that is what is tipping. We don’t know that for certain. I’m not one to guess and play the odds when electricity is involved.


Hi mark_m
I have an electrician coming in the next few weeks to re-place all smoke alarms - by law they have to be changed. The apartment was not lived in until 4 yrs ago. I will get the electrician to check all you have suggested, in the meantime I intend to start the oven every day & see what happens. I certainly will NOT have it going if I am not home. Thank you for your reply.


That’s great. I’ve only suggested a couple of items to illustrate the need to have everything checked properly. A reliable electrician will know all that needs to be done.

Is the oven consistently tripping at exactly 150C, which I’d expect takes some time to heat up to?
If so it is unlikely to be the heating elements being damp. Each cycle should have a slightly different result. The residual warmth in the oven after a couple of cycles will prolong the drying time. We found it could take 12-24 hrs to dry out industrial heating elements and achieve acceptable insulation test results.

I’ve never had that problem with a modern household electric oven. Or when living on the humid tropical coast and being away for extended periods of time.


I hadn’t suggested a DIY job to see what the problem is.

Even turning on a oven with a known problem poses a risk. It is not something which should be done unless one knows it is safe to do so.

Should it be moisture build-up in the element causing the fault, it will need to be removed and dried/replaced. Such can’t be done unless one is a qualified and licensed electrician.

A electrician will be able to determine if moisture within the element has caused the fault through simple testing/fault analysis.

Extended periods of time is a few years. Absorption is slow and won’t occur generally over a shorter period unless the element has been wet for a period because of cleaning or spills etc.

1 Like