Calibrating a domestic oven

[Rolyata]

For years, my wife has complained that her electric oven is too fierce.

Having just got an infra-red thermometer from Maplin ( partly because of comments made on this group ), I thought it should be easy enough to use it to check the actual oven temperature.

The obvious problem is what to use as a target.

The shelves are chrome, so are quite unsuitable, but although the side walls are black, the heating elements might make them hotter than the rest of the oven.

I do have some small black anodised aluminium heat sinks. I thought that anything designed to disspate heat ought to do just as good a job at absorbing heat, so I propose to use a small wire to suspendone from the middle of the centre shelf and check it's temperature periodically. Any obvious flaws with this idea ?

[Gordon Henderson]

I know this might sound too obvious, but all kitchen shops sell nice little round oven thermometers for a couple of quid which you can place on a shelf next to what you are cooking ...

Once you have that then you can use the dial marked Oven Temperature...

Gordon

[Dave Plowman (News)]

I've got one oven which is miles out. I checked it intitally with a Fluke DVM which has a temperature probe, with the probe at the top of the oven. My Maplin infra red pointed at the top back which is black is as near as dammit the same.

To get the usual 375F (190C) most 'quick' meals need, I have to set it at

475F. It's a wonder I never got food poisoning. ;-)

[Mary Fisher]

I used a simple mercury thermometer on a shelf - which is after all where the cooking food goes - for our slow oven which only has an indicator needle, no temperature markings.

I checked the reading then stuck small labels where the pointer was pointing at that time.

It's not rocket science, it doesn't have to be to the nearest degree.

Mary

[Dave Plowman (News)]

Which makes it all the worse that so many are miles out.

IMHO, many supermarket 'just heat' prepared foods err on the low side for cooking times, so add in a lower than correct temperature makes for possible health risks.

[Biggles]

I used my infra-red thermo to test the oven temperature, just out of interest really. At 150 degrees C oven setting, the IR was showing way above that (can't remember exactly, I think about 300 degrees) when pointing at the oven floor (black), which is where one set of elements are. It showed around 150 C when pointing at the sides (black) which have no elements. Which all goes to prove that at one moment in time, both IR thermo and the oven were in agreement. Your idea sounds spot on, but you may get a decent reading off the top & bottom (average out?) if the elements are in the sides.

Biggles

[Rolyata]

The small heatsinks that I have came in a bag of ten, five of them remain unused, so I put three in the oven in different places and used them as targets for the IR thermometer.

The oven is significantly hotter than it's temperature dial suggests, so my wife was right in thinking it was rather fierce.

I was surprised to see just how even the temperature is when the oven is fan assisted.

In the conventional mode, the temperature gradient is pretty much as you might expect.

[Badger]

We always used a thermocouple set-up to check the stats approximate accuracy, ovens usually go hotter due to loss of expansion fluid in the capillary thermo-switch BTW, which you may be able to adjust out on the stat.

Niel, former Belling Engineer.