11

Unlike microwaves, on every stove-top/oven I've used, a dial that controls the stove elements can be turned backward to click to the maximum setting, while the dial that controls the oven temperature, works in opposite direction.

Why is this?

  • Feels like a question for a mechanical engineer. Probably just a reflection of the differences in the hardware used to control each. – dennislees Mar 11 '14 at 2:20
  • I think we can only speculate but on a gas stovetop, my guess is that we often need 'highest' quite frequently and being gas, it's fairly instantaneous. Rarely do we need an oven to go to high and if we do, it's not going to be an immediate thing. – DA01 Mar 11 '14 at 2:20
  • Also on a gas stovetop, you need the 'high' by default to get the most gas flow to ignite it properly. Then dial-down to low once lit. – DA01 Mar 11 '14 at 2:21
  • The oven is an enclosed space, so the sudden burst of the flame is not going to hurt or scare anybody, but the open flame of a burner may. – PatomaS Mar 11 '14 at 2:42
  • 1
    In my oven, you have only one direction to turn the dial. – PatomaS Mar 11 '14 at 2:43
19

This is done for safety concerns. To my knowledge, this design is followed only on stoves. (I'll be pleased to know some other examples.)

Not just microwaves, every mechanical rotating controller, like volume on a music system or speed regulator in a fan, works the "normal way"; rotate clockwise to increase, counter clockwise to decrease, rotate all the way right for max, like so. Here's how this "normal way" would be a hazard on a stove:

There is a threshold minimum gas flow required for the flame to keep burning. If the gas flow becomes lower than that threshold, the flame will extinguish and the leaking gas will fill up the room. So, to make sure that you don't make the gas flow lower than that limit by mistake, they made you rotate it to the extreme right for lowest setting. This way, you wouldn't try to make the gas flow lower than that. If it was done the normal way, there was a chance that you'd unknowingly make the gas flow lower than the safety limit.

Also, like stated in the comments, when you start the stove, you initially want the gas flow to be maximum so that it's easier to ignite.

  • 1
    BlueFlame, by nickname you seem to be the person of trust here ;) And yes, this is what I wanted to write about it as well. One more thing: initially, the gas ovens were controlled directly with valves (probably there is a bit more technology implemented now, some electronical flow control or something), and it was valve mechanism limitation that let you add more or less gas as you turn the knob right or left - but opening the valve suddenly to its max could cause - with time - some leaks, which in case of ovens could lead to dramatic results. – Dominik Oslizlo Mar 11 '14 at 8:54
  • Fans also work the same way but for different reasons – Zach Saucier May 30 '16 at 18:25
0

Indeed, the burner control valve is designed for safety, and the key function is to ensure that a flame is maintained at all times. Otherwise an explosive amount of gas could build up and ignite. Upon opening the valve a full flow condition exists from the gas supply to the burner. This is the case for a couple reasons, first it enhances the effectiveness of the spark igniter, second the high flow rate ensures that the gas leaving the burner is traveling fast enough to prevent back ignition. If moving too slowly, the combustion reaction will continue to consume fuel, down into the burner and back through the line, which could result in an explosion. Once the burner is lit, the control valve is able to be throttled turning counter-clockwise, but. By only closing through the full open position, the flame will not be extinguished solely due to throttling. The difference between the burner and the oven is that the oven is not a continuously burning device. It is controlled by a thermostat and the gas is initiated automatically at a single flow rate. When the temp drops below a set point the burner kicks on and when it rises above, the burner turns off. That is why you set the oven to a temperature and not to a burn rate, therefore turning it through the high setting to off or to off through the low setting does not directly impact gas flow.

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