Oven & Cooker | Fault Finding & Repair Guides
- Published: Tuesday, 30 November 1999 00:00
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About Oven And Cooker Door Glass
On an all too regular basis we get posts in the forums about glass doors on cookers and ovens "exploding" or "shattering".
Normally when this happens people get a fright as when these glasses do fail they often do so with a bang and a rather dramatic helping of glass being thrown over the floor in front of the oven. Yes it is somewhat scary and a bit of a drama but it isn't as dangerous as many people make it out to be.
Before you dive in and order a replacement oven or cooker door glass please read the notes at the end of this tutorial, it is very important that you do so before you order a replacement spare part.
Oven Door Glass Safety, As Good As It Gets
Let's begin by stating clearly that no appliance can be made absolutely 100% guaranteed safe, it simply is not possible to account for every single instance and/or every single way in which an appliance will be used or abused. And, it really is unreasonable to expect any manufacturer to be able to do this.
When this does happen and the door glass shatters very often people tend to get pretty upset, all too often claiming the oven or cooker is dangerous, wanting to claim damages or a new appliance as this is a massive danger. Very often telling the manufacturer that they are concerned about their children who may have been nearby.
Can you tell that we've heard it all before?
To be quite honest, as with a lot of faults, what is often claimed is often ridiculous in many ways and the danger to anyone is normally overstated, in some cases quite considerably.
The fact is that these doors are made from glass, glass can break and occasionally does so. Should you wish absolute safety in this regard the only option ould be to buy an oven with a solid door.
Oven door glasses are made from a sort of toughened glass that, when it breaks, does so as harmlessly as possible much in the same way as a car window glass will do, thereby minimising the danger of cuts.
So, the outer door glass, if it ever shatters should be at a safe temperature in accordance with BS Standards and, whilst we may not think that they are stringent enough, they are what govern the temperature of the door glass.
If the inner glass shatters then, whilst hotter, it should all be contained within the oven cavity.
However you have to realise that, whilst not 100% safe as stated, modern ovens are as safe as they can be made within the constraints placed up the manufacturers by customer demands for pleasing designs and low prices.
So, as safe as it gets.
Why Oven And Cooker Door Glasses Shatter Or Explode
No-one will normally know why an oven door glass shatters, there can be any number of reasons and, normally, there is no adequate explanation as the evidence lies in a thousand tiny pieces. We have been told that this can be analysed forensically but this could prove to be costly and, if an owner insisted on this and it proved to be something that has been caused by the owner, they'd likley be faced with a sizeable bill for the service.
Over the years we have heard many explanations from the manufacturers the most plausible of which seems to be that a damp cloth is placed, hanging, on the door handle creating a temperature differential as the glass expands with the heat. This makes the one small area cooler, not expand as much and thereby stressing the glass and, in turn, causing it to shatter.
It could well be a flaw in the glass, it could be that someone bumps or strikes the glass causing a flaw and, eventually it shatters.
Interestingly this normally happens after a few years, it is pretty rare to replace these door glasses within the first year warranty period. This would tend to indicate that it is not a manufacturing flaw but something that has happened to the oven in use causing the failure.
With inner door glasses one of the reasons, that seems very logical, is that hot dishes rested on it or even spillage on the glass, creates the same effect as the damp cloth theory and that this stresses the glass.
So keeping the oven clean may also be a contributing factor, especially spillage on the door.
It is incredibly interesting however that on more expensive cookers and ovens, especially those with door ventilation or cooling as well as multiple door glasses, such as triple and quadruple glazing, that the fault appears far less common. This would lead you to the conclusion that cheaper built machines are more prone to the failure.
It is also vital that you check for other faults as thermostat failures can often lead to the problem, fault door hinges or even a faulty door seal. Basically anything that can allow the temperature to become unstable and it is not uncommon at all to find, when we do replace the door glass, that another fault is present and it has been ignored for some time. Should this be the case then the manufacturer will accept no claim for damage under any circumstance.
It has been noted by the BBC Watchdog program and others that movement in the glass, allowing it to rub against the oven door frame or any securing brackets, can "score" the glass allowing the surface to become weakened.
As the glass is tempered and formed under intense heat forming a toughened glass, any scores will degrade the integrity of the glass and even a small knock could cause it to shatter.
It is therefore absolutely vital that you ensure that any seal for the glass is maintained and that the glass is held firmly in place so that it cannot move.
Also noted is that “aggressive cleaning” can also cause the outer surface of the door glass to become weakened and this too can also lead to a premature failure of the glass. Essentially only non-abrasive cleaners should be used or you may end up with micro scores or scorches in the glass that can allow it to shatter.
We have seen people using scrapers and all manners of abrasive cleaners on theiroven doors to remove built up grease and so on and, obviosuly, if you have done this and scored the glass at all it will be weakened and likely to shatter. Likewise this could also explain why it takes some years before most of them do fail as it is liable to be a result of repeated cleaning with abrasive cleaners or scourers etc. In other words, it is highly liable that it is just caused by plain old wear and tear.
Types Of Oven And Cooker Door Glass Panels
There are several door glasses used on ovens and cooker but, almost all oven doors where the door is glass will have two glass panels, one out door glass and one inner door glass.
When you get a pyrolitic or self cleaning oven there will generally be at least three oven glass panels as an additional one is required between the normal two so as the outer panel stays within the British Standards for external temperature during a pyro cycle.
All are made from a special heat resistant glass and you will not be able to get a replacement cut to size if it is no longer available.
How To Replace An Oven Door Glass
Most oven door glass panels are pretty straightforward to change, except the bonded ones that we explain below, but you will need to work out exactly how the door is held together in order to free the outer door glass especially.
As a note, since we get asked a lot, most oven doors are not available as a complete door, they come in the constituent parts only that you have to assemble yourself.
Oven Inner Door Glass
The inner oven door glass is often designed to be removed for cleaning and so is quite often very straightforward to replace. Common door glass replacements on the likes of Beko built ovens and cookers, Diplomat, Hygena, Gorenje and so on are easy to do and usually fairly cheap as well.
Others are of course not so easy, even leaving aside the bonded oven door glasses.
There is an increasing pressure on oven and cooker manufacturers to reduce costs therefore we see more and more inner glass panels that are not so easy to swap as they are held in with a seal or bonded into place. This is cheaper on production basically but makes maintenance harder.
With these it is normally a case of working slowly, methodically and figuring out how the door glass was fitted.
Almost all inner oven door glass panels can be changed without the need to remove the door from the oven or cooker.
Outer Oven Door Glass
The outer oven door glass is usually held in place by a trim at the bottom of the oven door and the door handle, either by the screws through the back of the handle mounting points or by the handle running across the top of the oven door.
In some cases it is a lot easier to remove the oven door to replace the outer door glass but in many cases it is essential. To do this please see the article in this section on oven door hinge replacement that will explain how to do this in more depth or, if the oven door is designed to be removed for cleaning, your instruction manual will have instructions on how this is done.
Most outer door glasses are okay to replace so long as you are handy and apply some common sense to approaching the issue. Again, do not rush, take your time and figure it out as that's what we often have to do as well when we come across new fittings.
Internal Oven Door Glass
This is the glass we spoke about earlier, the extra internal door glass that is the one sandwiched in between the inner and outer door glass on some models of oven and cooker.
For these you will have to remove the outer door glass to get access to that glass panel. There is no way around this and it is often essential to remove the door to do these ones. It is worth noting that even we often think that these are a bit of a pain to get to and replace, it's certainly not a two minute job, even for a professional oven repair company. So, the advice is that if you don't think that you are up to it, call in a professional to do it for you.
Replacing A Glued Or Bonded Oven Door Glass
Very often the oven and cooker door glass is sealed, or glued, into place using a black high heat resistant glue known as "Ambersil Glue". This same glue is used in some cases to also fix door hinges to oven doors as well and is a black substance that resembles a sort of silicone sealant. The glue, which we use, is available from this link. This is especialy common on ovens and cookers made by Stoves, many of the inner oven door glass panels from them are glued into place.
You may also see oven door hinges or door hinge mounting brackets bonded to a door glass as well. Again, you must allow the time to cure the bonding agent when you replce or refit these or they will fall off. We learned this the hard way.
Once applied the glue must be allowed to properly set in the case of door glass replacement or indeed oven door hinge replacement for twenty four hours or the chances are that the repair will fail.
Ordering A New Oven Door Glass
These parts are very model number specific and we do mean that in the strongest possible way.
If you order for the wrong model or production run you will get the wrong replacement oven door glass, it is almost certain. Our advice would be to check prior to ordering (unless you are 100% sure) to make absolutely certain that you are ordering the correct glass panel.
If you don't you can get one that is the wrong size and will not fit, a different colour or have the mounting holes in the wrong place.
We do supply many of the more common door glasses in our online store but, due to the sheer number of them available in various colours and to fit many, many models we do generally supply these as special order spares on enquiry.
Cut To Size Oven Door Glass
We are asked if this can be done quite a bit and, we are sorry but there is absolutely no possibility whatsoever of this.
As the glass is toughened and formed specifically for each model it cannot be cut, it would simply shatter into a million pieces if you tried to cut it. So, it is not possible to do this under any circumstance.
As the panels are formed specifically they must be absolutely bang on for each model so, if the glass is obsolete or not available you cannot substitute another. The reason being that if the door glass does not fit exactly into place it could move, get scored and shatter. This makes fitting a door glass that is not specifically made for that model a potentially dangerous thing to do.