Kitchen extractor automation

[paulc]

People might like living in period homes but I don't believe anyone would like, or tolerate, genuinely authentic period living . . . unless they were minor royalty perhaps.

Don't know about previous generations, but the Victorians were very keen on adopting the latest gadgets. William Armstrong's pad at Cragside (built between 1869*1895) is claimed to be the first "smart home" in the world - https://www.nationaltrust.org.uk/cragside

[Flyfisher]

Exactly. Without this there would be no progress at all.

Sure, we can all bemoan certain aspects of 'progress' but my guess is that such moaning been a constant throughout human history. However I'm in little doubt that, in the round, today's standard of living for the vast majority of people is hugely better than anything in the past.

First world problems, perhaps?

[Flyfisher]

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[Feltwell]

Hi All,

Just though i would share another approach to "automation".
In the never ending fight against moisture when I installed our cooker extractor hood I wired it up to a microwave motion sensor so anytime you went near the cooker the extractor switched on.
(Automation was necessary to avoid the "sorry I forgot" attitude of some!)

However, the motion sensor approach had the downside that it would often mean the fan was running when there was no cooking happening and the fan was (to quote SWMBO) "loud enough for the whole village to hear" .

I was recently suggested to use a current sensor on the main cooker feed which I have just done and though I would share.



There is an adjustable current transducer which the main cooker (and a secondary socket feed) run through, when the cooker is switch on and draws current this closes the transducer output relay and then closes a timer latched relay which in turn switches the main extractor on. It is very sensitive as even the cooker LCD clock drew enough to trigger the transducer (until I adjusted it).

Very happy with the end result (and the wife is happy to).

Cheers,
Richard B.

p.s. Yes, the top gland was tightened

Sooooo - a couple of years on, all is still good I take it?

Can you share details please of what adjustable current transducer and timer latched relay you used? I have 2 digital showers to connect, current consumption will be very low but if your cooker clock can be picked up it should be OK. I was thinking I could use your idea to switch the extractor fans on whenever the shower is started - and in the room with a bath in it as well, add a flow switch to the bath feed.

This should stop my darling offspring (& Mrs F!) from either forgetting to switch the fan on, or only switching it on after their bath or shower, once all the condensation has already formed . I did try a fan with a humidistat a while ago, it was worse than useless.

[RBailey]

Sooooo - a couple of years on, all is still good I take it?

Yes, very happy. The timer is on a 5 minute overrun which is as much as management will tolerate but I sometime think 10 would be better.

Can you share details please of what adjustable current transducer and timer latched relay you used? I have 2 digital showers to connect, current consumption will be very low but if your cooker clock can be picked up it should be OK. I was thinking I could use your idea to switch the extractor fans on whenever the shower is started - and in the room with a bath in it as well, add a flow switch to the bath feed.

In the end I used this current sensor:
https://www.amazon.co.uk/gp/product/B08 ... UTF8&psc=1
it is o.5 to 50 A input. As the sensor is self powered I was worried about the full cooker draw smoking the sensor.

I also bought one of these:
https://www.amazon.co.uk/gp/product/B08 ... UTF8&psc=1
but as its only 0.2 - 30 A i didn't use it.

I have the wire only once through the transducer but apparently twice will increase the sensitivity (twice the input coil "windings").

This is the timer relay I used.
https://www.amazon.co.uk/gp/product/B07 ... UTF8&psc=1

I also got a bunch of DIN rail bits, because I wanted to as I'd never played with it before.
(Some okay selection kits on Amazon as well.)

Cheers,
Richard B.

[Feltwell]

Great, thanks Richard!

[CliffordPope]

We just turn the (period, brown bakelite, 1950s) extractor fan on when there is something to extract - steam, strong cooking smells, etc.
But not when the stove is lit, because that sucks air back down the flue and we'd get smoke in the kitchen.

[worms]

We just turn the (period, brown bakelite, 1950s) extractor fan on when there is something to extract - steam, strong cooking smells, etc.

Ooooh, that's fancy!

We tend to just open the front and back windows to establish a through-breeze!

[RBailey]

We

It's the lack of "we" that is the problem at our house, I do, nobody else does
Hence the automation. We also have a fair few lights automated or on PIR's and automatic door closers on children's bedrooms for the same reason.

Interesting on the reverse draft.

Cheers,
Richard B.

[Feltwell]

I also bought one of these:
https://www.amazon.co.uk/gp/product/B08 ... UTF8&psc=1
but as its only 0.2 - 30 A i didn't use it.

I have the wire only once through the transducer but apparently twice will increase the sensitivity (twice the input coil "windings").

Old thread alert!

Richard B was kind enough to send me his spare current sensing switch - fitted it to the fan in my en-suite shower today, with the power feed cable to the shower through the hole in the switch - shower on, nothing, fan as dead as a dodo. Opened up the cable outer and extended the live wire, put only that through the hole but 3 times back & forth - still nothing.

Checked the shower unit, it only pulls 20w at most, which is less than 0.1A - the switch is rated to work from 0.2A upwards. So, as Richard says above, recognising that the magnetic field produced by the wire passing through the switch will be amplified the more the wire is wound around the switch, I wound it around the switch and through the hole 5 times - hey presto, it works!

So now, as soon as you turn the shower on the extractor fan starts, no chance for the family to forget - when your shower ends a timer takes over and it keeps running, after about 5 minutes the shower valve purges itself which conveniently resets the timer, so it runs for about 10 minutes in total.

Alternatively - next to the sink in the bathroom is a pullcord which looks like a 2nd light switch, pull that and it makes a momentary connection only and sets the fan off on a 5 minute timer - to purge the room of any lingering malodours from activities other than showering, shall we say.

So, with that and the window in the room all renovated now and easy to open, we are about sorted for ventilation! I shall post some overall project pictures when I get a chance. as everyone seems to like those - although this is not a "period" bathroom at all it was a major refit, involving moving a wall and other structural work.

[Gothichome]

We just turn the (period, brown bakelite, 1950s) extractor fan on when there is something to extract - steam, strong cooking smells, etc.

Ooooh, that's fancy!

We tend to just open the front and back windows to establish a through-breeze!

We just depend on the natural drafts and fresh air ingress that naturally comes with an old home

[CliffordPope]

We just depend on the natural drafts and fresh air ingress that naturally comes with an old home

Yes, but that's a bit erratic, and liable to carry the fried fish smell or the damp air vapour off somewhere else.
Draughts come in - only heat goes out

[RBailey]

So now, as soon as you turn the shower on the extractor fan starts, no chance for the family to forget - when your shower ends a timer takes over and it keeps running, after about 5 minutes the shower valve purges itself which conveniently resets the timer, so it runs for about 10 minutes in total.

Alternatively - next to the sink in the bathroom is a pullcord which looks like a 2nd light switch, pull that and it makes a momentary connection only and sets the fan off on a 5 minute timer - to purge the room of any lingering malodours from activities other than showering, shall we say.

Congratulations.

I like the idea of a momentary switch as well. Simple, effective and "family proof".

Cheers,
Richard B.