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  #1   Report Post  
flashgorman
 
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Default Extractor fan not extracting

Hi,

I have a hood type extractor fan over my hob. Lately this has given up on
its extracting duties. When I turn it on theres the usual whizzing noises
but no air is being sucked up into the hood. I took the cover off the hood
and removed the filter (pretty clean). There's a big fan that spins round at
an impressive rate but I can't feel any updraught of air into it. I climbed
on to the kitchen roof and checked that the vents are clear and you can feel
a slight draught coming from the vent.

Any clues?

--
Flash Gorman.

http://www.flashgorman.com


  #2   Report Post  
Alex
 
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Default Extractor fan not extracting

do a smoke type test to estabilish what draw is on the vent


  #3   Report Post  
flashgorman
 
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Default Extractor fan not extracting


"Alex" wrote in message
...
do a smoke type test to estabilish what draw is on the vent

ok, any pointers as to how I would do this? I have tried boiling a kettle
under the hood and the steam can be seen going anywhere but into the hood.


  #4   Report Post  
 
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Default Extractor fan not extracting

flashgorman wrote:
Hi,

I have a hood type extractor fan over my hob. Lately this has given up on
its extracting duties. When I turn it on theres the usual whizzing noises
but no air is being sucked up into the hood. I took the cover off the hood
and removed the filter (pretty clean). There's a big fan that spins round at
an impressive rate but I can't feel any updraught of air into it. I climbed
on to the kitchen roof and checked that the vents are clear and you can feel
a slight draught coming from the vent.

Any clues?

Are you sure it really used to work?

If it really has got worse there's not much that can go wrong, check
that the fan is spinning at the right speed, clean the filter
thoroughly and then the only remaining possibility that I can think
of is a nest or some such in the duct.

--
Chris Green
  #5   Report Post  
flashgorman
 
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Default Extractor fan not extracting


wrote in message ...
flashgorman wrote:
Hi,

I have a hood type extractor fan over my hob. Lately this has given up

on
its extracting duties. When I turn it on theres the usual whizzing

noises
but no air is being sucked up into the hood. I took the cover off the

hood
and removed the filter (pretty clean). There's a big fan that spins

round at
an impressive rate but I can't feel any updraught of air into it. I

climbed
on to the kitchen roof and checked that the vents are clear and you can

feel
a slight draught coming from the vent.

Any clues?

Are you sure it really used to work?

Indeed. It makes a lot of noise and the sucking-up-ness used to be
impressive to behold.

If it really has got worse there's not much that can go wrong, check
that the fan is spinning at the right speed, clean the filter
thoroughly


Tried it without the filter at all and still no joy


and then the only remaining possibility that I can think
of is a nest or some such in the duct.


Have removed top of the ducts (appear to be two) on the roof and can't see
anything. If I disconnected the pipe from the top of the fan should I then
be able to feel the fan sucking up (and hence prove the pipe is blocked) or
will it suck without the pipe?

Chris Green





  #6   Report Post  
JoeJoe
 
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Default Extractor fan not extracting

A long shot - but may help...

I had a similar problem with a brand new extractor that did not seem to do
anything either.

When I finally opened the cover a few weeks later I discovered that there is
a leaver inside that should be set depending on whether you extract to the
outside, or to the inside (filtering only). Needless to say, mine was set to
external extraction mode, which was blocked with a cover, as I only wanted
it to filter. The smell from the fan was interesting too... Pretty
embarrassing I must say, although it wasn't me who fitted it.

May be worth checking whether you have such settings, and whether it moved.

Just my 2p-worth.

J.

"flashgorman" wrote in message
...
Hi,

I have a hood type extractor fan over my hob. Lately this has given up on
its extracting duties. When I turn it on theres the usual whizzing noises
but no air is being sucked up into the hood. I took the cover off the hood
and removed the filter (pretty clean). There's a big fan that spins round

at
an impressive rate but I can't feel any updraught of air into it. I

climbed
on to the kitchen roof and checked that the vents are clear and you can

feel
a slight draught coming from the vent.

Any clues?

--
Flash Gorman.

http://www.flashgorman.com




  #7   Report Post  
flashgorman
 
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Default Extractor fan not extracting


"JoeJoe" wrote in message
...
A long shot - but may help...

I had a similar problem with a brand new extractor that did not seem to do
anything either.

When I finally opened the cover a few weeks later I discovered that there

is
a leaver inside that should be set depending on whether you extract to the
outside, or to the inside (filtering only). Needless to say, mine was set

to
external extraction mode, which was blocked with a cover, as I only wanted
it to filter. The smell from the fan was interesting too... Pretty
embarrassing I must say, although it wasn't me who fitted it.

May be worth checking whether you have such settings, and whether it

moved.

Just my 2p-worth.

Cheers ,sorry should have mentioned that I have found said lever and its
set to external.



  #8   Report Post  
MBQ
 
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Default Extractor fan not extracting

"flashgorman" wrote in message ...
"JoeJoe" wrote in message
...
A long shot - but may help...

I had a similar problem with a brand new extractor that did not seem to do
anything either.

When I finally opened the cover a few weeks later I discovered that there

is
a leaver inside that should be set depending on whether you extract to the
outside, or to the inside (filtering only). Needless to say, mine was set

to
external extraction mode, which was blocked with a cover, as I only wanted
it to filter. The smell from the fan was interesting too... Pretty
embarrassing I must say, although it wasn't me who fitted it.

May be worth checking whether you have such settings, and whether it

moved.

Just my 2p-worth.

Cheers ,sorry should have mentioned that I have found said lever and its
set to external.


My new hood had both a paper filter and a charcoal one. The charcoal
one is removed for external venting since you don't need to get rid of
smells. Maybe yours wasn't and is now blocked up. What I'm saying is
check if there is another filter.

MBQ
  #9   Report Post  
Richard Sterry
 
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Default Extractor fan not extracting

flashgorman wrote:
"Richard Sterry" wrote in message
...
flashgorman wrote:
Hi,

I have a hood type extractor fan over my hob. Lately this has given up
on its extracting duties. When I turn it on theres the usual whizzing
noises but no air is being sucked up into the hood. I took the cover
off the hood and removed the filter (pretty clean). There's a big fan
that spins round at an impressive rate but I can't feel any updraught
of air into it. I climbed on to the kitchen roof and checked that the
vents are clear and you can feel a slight draught coming from the vent.

Any clues?


Is there a build-up of fat/grease somewhere in the ducting?

Not as far as I can insert an arm, James Herriot, style, at either end.


....then it would appear to be defying the laws of physics! If the ducts are
clear, the outlet grill is clear, the recirculate/extract lever is in the
right position, and the fan is going round at a decent speed, then it MUST
draw air through. If air is not being drawn through, then one of the
previous assumptions/observations must be wrong.

Unless it's the unknown factor 'X' of course. ;-)

Rick


  #10   Report Post  
John Rumm
 
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Default Extractor fan not extracting

Richard Sterry wrote:

...then it would appear to be defying the laws of physics! If the ducts are
clear, the outlet grill is clear, the recirculate/extract lever is in the
right position, and the fan is going round at a decent speed, then it MUST
draw air through. If air is not being drawn through, then one of the
previous assumptions/observations must be wrong.

Unless it's the unknown factor 'X' of course. ;-)


Like a burnt out or shorted motor winding? It would still spin but with
far less force....

--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/


  #11   Report Post  
Richard Sterry
 
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Default Extractor fan not extracting

John Rumm wrote:
Richard Sterry wrote:

...then it would appear to be defying the laws of physics! If the ducts
are clear, the outlet grill is clear, the recirculate/extract lever is
in the right position, and the fan is going round at a decent speed,
then it MUST draw air through. If air is not being drawn through, then
one of the previous assumptions/observations must be wrong.

Unless it's the unknown factor 'X' of course. ;-)


Like a burnt out or shorted motor winding? It would still spin but with
far less force....


Well, the original poster said it "spins round at an impressive rate", but I
guess that's purely subjective - depends on how easily impressed he is! ;-)

Rick


  #12   Report Post  
raden
 
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Default Extractor fan not extracting

In message , flashgorman
writes

"Alex" wrote in message
...
do a smoke type test to estabilish what draw is on the vent

ok, any pointers as to how I would do this? I have tried boiling a kettle
under the hood and the steam can be seen going anywhere but into the hood.

Smoke matches from a CH merchant

--
geoff
  #13   Report Post  
flashgorman
 
Posts: n/a
Default Extractor fan not extracting


"raden" wrote in message
news
In message , flashgorman
writes

"Alex" wrote in message
...
do a smoke type test to estabilish what draw is on the vent

ok, any pointers as to how I would do this? I have tried boiling a kettle
under the hood and the steam can be seen going anywhere but into the

hood.

Smoke matches from a CH merchant

Cheers, ta.


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