We have a Whirlpool tumble drier (about 5 years old), on which the red
warning LED, which means that the lint filter needs emptying, keeps
lighting up when there's hardly anything in the filter, so it's not drying
clothes (and it's been ****ing it down with rain all weekend here).
Doesn't appear to be anything else blocking the ventilation pathway either.

Is this symptomatic of anything obvious that can be fixed?

--
David

On 15/06/2014 22:02, Lobster wrote:
We have a Whirlpool tumble drier (about 5 years old), on which the red
warning LED, which means that the lint filter needs emptying, keeps
lighting up when there's hardly anything in the filter, so it's not drying
clothes (and it's been ****ing it down with rain all weekend here).
Doesn't appear to be anything else blocking the ventilation pathway either.

Is this symptomatic of anything obvious that can be fixed?

We had a Whirlpool tumble drier that started doing that too.

You can try vacuuming out any loose lint in the filter housing.

If it's a condenser model you can try cleaning out the
heat exchanger unit. (Bewa If you haven't done it for
a while dirty water may gush out over your floor.)

However we kept the lint filter and the condenser heat
exchanger clean and the warning light still kept coming on
so we just learnt to ignore it. It ran happily like that
for some years (until the drive mechanism seized up at
10 years old and we got a new dryer).



--
Graham Nye
news(a)thenyes.org.uk

Kind of begs the question what exactly is the light using as a sensor?
Could it be that its overheating and its really a thermostat issue?
Brian

--
From the Sofa of Brian Gaff Reply address is active
"Graham Nye" wrote in message
...
On 15/06/2014 22:02, Lobster wrote:
We have a Whirlpool tumble drier (about 5 years old), on which the red
warning LED, which means that the lint filter needs emptying, keeps
lighting up when there's hardly anything in the filter, so it's not
drying
clothes (and it's been ****ing it down with rain all weekend here).
Doesn't appear to be anything else blocking the ventilation pathway
either.

Is this symptomatic of anything obvious that can be fixed?

We had a Whirlpool tumble drier that started doing that too.

You can try vacuuming out any loose lint in the filter housing.

If it's a condenser model you can try cleaning out the
heat exchanger unit. (Bewa If you haven't done it for
a while dirty water may gush out over your floor.)

However we kept the lint filter and the condenser heat
exchanger clean and the warning light still kept coming on
so we just learnt to ignore it. It ran happily like that
for some years (until the drive mechanism seized up at
10 years old and we got a new dryer).



--
Graham Nye
news(a)thenyes.org.uk

On Mon, 16 Jun 2014 08:50:47 +0100, Brian Gaff wrote:

Kind of begs the question what exactly is the light using as a sensor?

Good question. I can think of a few ways of detecting a blocked
filter:

1) Pressure on the feed side relative to atmospheric.
2) Pressure across the filter.
3) Volume of air flowing.
4) Temperature of air flowing.

4) I don't like, it's not fail safe. As the filter gets more and more
blocked I can see the temp of the air flow (because there isn't very
much) not rising above the threshold. So, to the dumb user, the fault
appears to go away.

3) Air mass sensors are common enough in cars but I think they are
bit delicate and all we need to know here is air flowing freely not
how much air is flowing. Also electronic rather than a passive
switch.

Which leaves 1) or 2). 1) is the simplest, just a connection into the
"high pressure" side of the filter, leading to a chamber with a
diaphragm across it open to the atmosphere the other side. Pressure
goes up diaphragm moves operates switch. Tube feeding it could get
blocked. Very similar to water level detection in washing machines.

--
Cheers
Dave.

In article o.uk,
"Dave Liquorice" writes:
On Mon, 16 Jun 2014 08:50:47 +0100, Brian Gaff wrote:

Kind of begs the question what exactly is the light using as a sensor?

Good question. I can think of a few ways of detecting a blocked
filter:

1) Pressure on the feed side relative to atmospheric.
2) Pressure across the filter.
3) Volume of air flowing.
4) Temperature of air flowing.

4) I don't like, it's not fail safe. As the filter gets more and more
blocked I can see the temp of the air flow (because there isn't very
much) not rising above the threshold. So, to the dumb user, the fault
appears to go away.

3) Air mass sensors are common enough in cars but I think they are
bit delicate and all we need to know here is air flowing freely not
how much air is flowing. Also electronic rather than a passive
switch.

Which leaves 1) or 2). 1) is the simplest, just a connection into the
"high pressure" side of the filter, leading to a chamber with a
diaphragm across it open to the atmosphere the other side. Pressure
goes up diaphragm moves operates switch. Tube feeding it could get
blocked. Very similar to water level detection in washing machines.

Another way in an airflow which isn't too hot is to use a thermister
which is self-heated (by current flow) and relies on the draft to
cool it. Read off voltage across it. If the thermister itself was
covered in lint, that would trigger it.

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]