I'm about to fit a hob extractor and got to thinking it would be useful
if it could turn itself on, possibly triggered by heat and/or humidity.
Has anyone done this? what sensors did you use?

Dave

On Wed, 13 Jul 2005 23:45:54 +0000 (UTC),it is alleged that Dave
spake thusly in uk.d-i-y:

I'm about to fit a hob extractor and got to thinking it would be useful
if it could turn itself on, possibly triggered by heat and/or humidity.
Has anyone done this? what sensors did you use?

Dave

My thought would be something akin to this:
http://www.hoytmeter.com/multirlayac...rlayaccur.html

I have no clue what the wiring regulations would have to say about it
though, or where to obtain one at a reasonable cost.

You'd also have to have a large time delay, like in the order of a
minute or 2, to prevent the cycling of the hob thermostats from
turning the hood on and off.

--
Life is like a hot bath. It feels good while you're in it, but the
longer you stay in, the more wrinkled you get.
- Robbert Oustin

"Dave" wrote in message
...
I'm about to fit a hob extractor and got to thinking it would be useful
if it could turn itself on, possibly triggered by heat and/or humidity.
Has anyone done this? what sensors did you use?

Dave

How about a thermostat inside the hood, above the cover. Something like a
simple bi-metal strip switch fitted in line with the on off switch on the
front of the hood would work I'd have thought.

"BigWallop" wrote in message
. uk...

"Dave" wrote in message
...
I'm about to fit a hob extractor and got to thinking it would be useful
if it could turn itself on, possibly triggered by heat and/or humidity.
Has anyone done this? what sensors did you use?

Dave

How about a thermostat inside the hood, above the cover. Something like a
simple bi-metal strip switch fitted in line with the on off switch on the
front of the hood would work I'd have thought.


Why bother ... ? On mine it's switching a push button ON/OFF; Slow/Med/Fast.
I frequently want the extractor fan ON (without the hob) to act as an
room extractor - particularly when grilling 'stuff' utilising the
oven's grill; or venting steam when using the steamer; or venting fumes
when using sandwich toaster or fat-fryer. In other words having the
extractor fan interlocked with the hob would be inconvenient.
Besides ... if you can't remember to turn the device ON when you're
presumably standing at the hob ... !

--

Brian

Brian Sharrock wrote:
"BigWallop" wrote in message
. uk...

"Dave" wrote in message
...

I'm about to fit a hob extractor and got to thinking it would be useful
if it could turn itself on, possibly triggered by heat and/or humidity.
Has anyone done this? what sensors did you use?

Dave


How about a thermostat inside the hood, above the cover. Something like a
simple bi-metal strip switch fitted in line with the on off switch on the
front of the hood would work I'd have thought.



Why bother ... ? On mine it's switching a push button ON/OFF; Slow/Med/Fast.
I frequently want the extractor fan ON (without the hob) to act as an
room extractor - particularly when grilling 'stuff' utilising the
oven's grill; or venting steam when using the steamer; or venting fumes
when using sandwich toaster or fat-fryer. In other words having the
extractor fan interlocked with the hob would be inconvenient.
Besides ... if you can't remember to turn the device ON when you're
presumably standing at the hob ... !


The idea isn't to interlock the extract and hob but to add an auto mode
that would respond to anything that was happening in the kitchen, as
well as what was happening just below it. There'd obviously still be the
manual controls.
Why bother? - it's for the other more members of the family who are more
memory-challenged than me - I'm perfect, like most uk.d-i-y'ers ;-)

Dave

In article , Dave
writes
Brian Sharrock wrote:

Why bother ... ? On mine it's switching a push button ON/OFF; Slow/Med/Fast.
I frequently want the extractor fan ON (without the hob) to act as an
room extractor - particularly when grilling 'stuff' utilising the
oven's grill; or venting steam when using the steamer; or venting fumes
when using sandwich toaster or fat-fryer. In other words having the
extractor fan interlocked with the hob would be inconvenient.
Besides ... if you can't remember to turn the device ON when you're
presumably standing at the hob ... !


The idea isn't to interlock the extract and hob but to add an auto mode
that would respond to anything that was happening in the kitchen, as
well as what was happening just below it. There'd obviously still be the
manual controls.
Why bother? - it's for the other more members of the family who are more
memory-challenged than me - I'm perfect, like most uk.d-i-y'ers ;-)

No need to justify yourself mate, here goes:

If you just wanted something to come on when the cooker was in use then
a simple bi-metal thermostat in the hood would probably do the job as the
temperature there will rise pretty high and pretty quickly. The setting would
need to be low enough to switch on quickly but high enough not to switch
off as loads of (slightly cooler) air starts to rush past it when the fan comes
on :-). Tolerance of capsule (safe) stats is high so you may find it difficult
to get a happy balance of fan on vs fan off.

Also, this would not cover your late breaking requirement for the system to
be sensitive to other activities in the kitchen. For that I reckon that a
humidistat may suit better, as long as all your heat making activities
create water vapour (cooking, ironing, heavy breathing etc). Here's one
form TLC http://www.tlc-direct.co.uk/Products/BGREMHM.html , mounted
unobtrusively in the room, say under a cabinet, close to the hob, I think
that would do the job. Main issue is cost, that'll be 30quid with the vat but
don't expect to find one cheaper, they are expensive.

Btw: Humidistats can be a bit of a PITA for running on, if your fan is a
multispeed one, maybe dedicate the lowest speed switch position to the
humidistat (connect in series) so it can be turned off.
--
fred

"fred" wrote in message ...
In article , Dave
writes
Brian Sharrock wrote:

Why bother ... ? On mine it's switching a push button ON/OFF;
Slow/Med/Fast.
I frequently want the extractor fan ON (without the hob) to act as an
room extractor - particularly when grilling 'stuff' utilising the
oven's grill; or venting steam when using the steamer; or venting fumes
when using sandwich toaster or fat-fryer. In other words having the
extractor fan interlocked with the hob would be inconvenient.
Besides ... if you can't remember to turn the device ON when you're
presumably standing at the hob ... !


The idea isn't to interlock the extract and hob but to add an auto mode
that would respond to anything that was happening in the kitchen, as
well as what was happening just below it. There'd obviously still be the
manual controls.
Why bother? - it's for the other more members of the family who are more
memory-challenged than me - I'm perfect, like most uk.d-i-y'ers ;-)

No need to justify yourself mate, here goes:

If you just wanted something to come on when the cooker was in use then
a simple bi-metal thermostat in the hood would probably do the job as the
temperature there will rise pretty high and pretty quickly. The setting
would
need to be low enough to switch on quickly but high enough not to switch
off as loads of (slightly cooler) air starts to rush past it when the fan
comes
on :-). Tolerance of capsule (safe) stats is high so you may find it
difficult
to get a happy balance of fan on vs fan off.

Also, this would not cover your late breaking requirement for the system
to
be sensitive to other activities in the kitchen. For that I reckon that a
humidistat may suit better, as long as all your heat making activities
create water vapour (cooking, ironing, heavy breathing etc). Here's one
form TLC http://www.tlc-direct.co.uk/Products/BGREMHM.html , mounted
unobtrusively in the room, say under a cabinet, close to the hob, I think
that would do the job. Main issue is cost, that'll be 30quid with the vat
but
don't expect to find one cheaper, they are expensive.

Btw: Humidistats can be a bit of a PITA for running on, if your fan is a
multispeed one, maybe dedicate the lowest speed switch position to the
humidistat (connect in series) so it can be turned off.
--
fred

Alternatively .... : save yourself the thirty-odd quid (perhaps
five-odd quid direct to Gordon Brown?) for the humidistat and/or
thermostat and ... SPEAK SLOWLY AND CLEARLY to your memory-challenged
others! "HOB ON! FAN ON!" Repeat as necessary until message gets through.
Thirty Quid will buy a lot of D-I-Y thingies!

--

Brian

In article , Brian Sharrock
writes


Alternatively .... : save yourself the thirty-odd quid (perhaps
five-odd quid direct to Gordon Brown?) for the humidistat and/or
thermostat and ... SPEAK SLOWLY AND CLEARLY to your memory-challenged
others! "HOB ON! FAN ON!" Repeat as necessary until message gets through.
Thirty Quid will buy a lot of D-I-Y thingies!

I think you've suggested that already, I've no problem helping someone out
who chooses to pamper themselves.
--
fred