On 23/01/2020 20:09, charles wrote:
In article ,
ARW wrote:
On 23/01/2020 15:07, Andy Burns wrote:
Thomas Prufer wrote:

https://youtu.be/Qif9psHqymY suggests that some Eletrolux hobs
are just dropped in place.
Do any UK hobs daisy-chain off the oven like that?


I have seen it done. And some of the posh hobs automatically turn on the
extractor hoods when you turn them on.

Some 7 or 8 years ago, I was informed, by someone I trusted, that in
commercial premises you had to have the extractor fan running before you
could get a supply to a gas cooker. Easily dome with a solenoid in the gas
supply.



The person you trust is correct.

There is however more to it than just a switch to turn on the fan and
operate the solenoid in most cases.

There are usually two fans in such properties an intake and an out-take
and they are often variable speed fans.

Normally a fan control unit monitors the fans and shuts the gas off if
either fail. The unit uses a couple of potentiometers that you have to
set to to determine the detection range when the fans are on the slowest
setting.

The ones I have worked on also have an emergency "run for 30 minutes
even if a fan has failed" button to press if you take the front cover
off. That is supposed to let you finish what you are cooking before I
arrive and bypass the con

--
Adam