Guess which bit of electrical kit in my house has the scorch marks from
an overheating electrical connection?

Yup, the smoke alarm. I think the pin wasn't mounted to the board very well.

Firex FADC230

Any preferred replacements? Mains/battery, ionising detector, mounted to
a batten on the ceiling, so no tricky bits. Screwfix have a "Dicon", a
"Fireangel", and a "Firstalert" - the latter two are 10 year battery
models. I see my Firex has a 10 year life despite being mains powered -
I guess this is supposed to be the lifetime of the radiation source.

On May 16, 8:46 am, Clive George wrote:

I see my Firex has a 10 year life despite being mains powered -
I guess this is supposed to be the lifetime of the radiation source.

The half life of Americium-241 is 432 years, so it should outlast the
house.

In article ,
Matty F writes:
On May 16, 8:46 am, Clive George wrote:

I see my Firex has a 10 year life despite being mains powered -
I guess this is supposed to be the lifetime of the radiation source.

The half life of Americium-241 is 432 years, so it should outlast the
house.

The life is more to do with inaccessible parts becoming too dirty,
and affecting operation (leakage of the ionisation current causing
a false alarm and/or obscuring of the cell causing delayed/no alarm).
However, as time increases, I guess there's also increasing chance
of electronic failure having happened, as in the OP's case.

The 10 year batteries are lithium (but usually not changable).
You can buy lithium PP3's to put in any PP3 battery model.

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

On Sun, 16 May 2010 07:59:22 +0000 (UTC), Andrew Gabriel wrote:

In article ,
Matty F writes:
On May 16, 8:46 am, Clive George wrote:

I see my Firex has a 10 year life despite being mains powered -
I guess this is supposed to be the lifetime of the radiation source.

The half life of Americium-241 is 432 years, so it should outlast the
house.

The life is more to do with inaccessible parts becoming too dirty,
and affecting operation (leakage of the ionisation current causing
a false alarm and/or obscuring of the cell causing delayed/no alarm).
However, as time increases, I guess there's also increasing chance
of electronic failure having happened, as in the OP's case.

The 10 year batteries are lithium (but usually not changable).
You can buy lithium PP3's to put in any PP3 battery model.

I've never seen the point in the alarms with fixed batteries, unless it is
to prevent people taking the batteries out because of nuisance alarms. If
that is the case, they'll simply throw the whole thing away or pull
connections out!

Our alarms have replaceable batteries, a simple button test and if the
battery gets low, the alarm starts beeping at irregular intervals -
although it can take a few days to work out what's beeping, as they are so
infrequent and we have many other things, including children's toys that
beep.

SteveW

In article ,
Steve Walker writes:

I've never seen the point in the alarms with fixed batteries, unless it is
to prevent people taking the batteries out because of nuisance alarms. If
that is the case, they'll simply throw the whole thing away or pull
connections out!

It's because research shows a significant proportion of battery
alarms never get the battery replaced, so after the first year,
they sit there disabled.

Our alarms have replaceable batteries, a simple button test and if the
battery gets low, the alarm starts beeping at irregular intervals -
although it can take a few days to work out what's beeping, as they are so
infrequent and we have many other things, including children's toys that
beep.

Mine are all PP3 replaceable battary types, but they all have a
PP3-sized module in them which powers them from the 12V burglar
alarm, and generates a signal back to the alarm when they start
drawing enough power for the sounder. So I never have to change
any smoke detector batteries.

When I put some in my parents' home, I fitted them with the
lithum (10 year) PP3s, so we don't have to arse around with
battery changing. Since then, they've had an extention and also
have mains interlinked ones, but I didn't bother removing the
battery ones.

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

On 16 May, 13:09, (Andrew Gabriel) wrote:
In article ,
* * * * Steve Walker writes:



I've never seen the point in the alarms with fixed batteries, unless it is
to prevent people taking the batteries out because of nuisance alarms. If
that is the case, they'll simply throw the whole thing away or pull
connections out!

It's because research shows a significant proportion of battery
alarms never get the battery replaced, so after the first year,
they sit there disabled.

Our alarms have replaceable batteries, a simple button test and if the
battery gets low, the alarm starts beeping at irregular intervals -
although it can take a few days to work out what's beeping, as they are so
infrequent and we have many other things, including children's toys that
beep.

Mine are all PP3 replaceable battary types, but they all have a
PP3-sized module in them which powers them from the 12V burglar
alarm, and generates a signal back to the alarm when they start
drawing enough power for the sounder. So I never have to change
any smoke detector batteries.

When I put some in my parents' home, I fitted them with the
lithum (10 year) PP3s, so we don't have to arse around with
battery changing. Since then, they've had an extention and also
have mains interlinked ones, but I didn't bother removing the
battery ones.

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

Replace with A firex 4870 or 4973 (optical); try TLC or QVS websites
http://www.tlc-direct.co.uk/Manufacturers/Kidde/Smoke_Alarms_Mains_Alkaline/index.html
http://www.qvsdirect.com/_search.php?page=1&q=firex

"Clive George" wrote in message
o.uk...
Guess which bit of electrical kit in my house has the scorch marks from an
overheating electrical connection?

Yup, the smoke alarm. I think the pin wasn't mounted to the board very
well.

Firex FADC230

Any preferred replacements? Mains/battery, ionising detector, mounted to a
batten on the ceiling, so no tricky bits. Screwfix have a "Dicon", a
"Fireangel", and a "Firstalert" - the latter two are 10 year battery
models. I see my Firex has a 10 year life despite being mains powered - I
guess this is supposed to be the lifetime of the radiation source.


I am surprised there were any scorchmarks due to the very small current that
is used.

A direct replacement is probably the easiest and having fitted hundreds of
these alarms I can assure you that it is not a known problem.

Adam

On 16/05/2010 14:39, ARWadsworth wrote:
"Clive wrote in message
o.uk...
Guess which bit of electrical kit in my house has the scorch marks from an
overheating electrical connection?

Yup, the smoke alarm. I think the pin wasn't mounted to the board very
well.

Firex FADC230

Any preferred replacements? Mains/battery, ionising detector, mounted to a
batten on the ceiling, so no tricky bits. Screwfix have a "Dicon", a
"Fireangel", and a "Firstalert" - the latter two are 10 year battery
models. I see my Firex has a 10 year life despite being mains powered - I
guess this is supposed to be the lifetime of the radiation source.


I am surprised there were any scorchmarks due to the very small current that
is used.

Me too. But it is nicely brown, and the relevant pin did fall out when I
touched it.

A direct replacement is probably the easiest and having fitted hundreds of
these alarms I can assure you that it is not a known problem.

Thanks.

"Clive George" wrote in message
o.uk...
On 16/05/2010 14:39, ARWadsworth wrote:
"Clive wrote in message
o.uk...
Guess which bit of electrical kit in my house has the scorch marks from
an
overheating electrical connection?

Yup, the smoke alarm. I think the pin wasn't mounted to the board very
well.

Firex FADC230

Any preferred replacements? Mains/battery, ionising detector, mounted to
a
batten on the ceiling, so no tricky bits. Screwfix have a "Dicon", a
"Fireangel", and a "Firstalert" - the latter two are 10 year battery
models. I see my Firex has a 10 year life despite being mains powered -
I
guess this is supposed to be the lifetime of the radiation source.


I am surprised there were any scorchmarks due to the very small current
that
is used.

Me too. But it is nicely brown, and the relevant pin did fall out when I
touched it.

Bloody hand fisted electricians that cannot do their job properly when
installing them:-)

Adam

"Steve Walker" wrote in message
...
On Sun, 16 May 2010 07:59:22 +0000 (UTC), Andrew Gabriel wrote:

In article
,
Matty F writes:
On May 16, 8:46 am, Clive George wrote:

I see my Firex has a 10 year life despite being mains powered -
I guess this is supposed to be the lifetime of the radiation source.

The half life of Americium-241 is 432 years, so it should outlast the
house.

The life is more to do with inaccessible parts becoming too dirty,
and affecting operation (leakage of the ionisation current causing
a false alarm and/or obscuring of the cell causing delayed/no alarm).
However, as time increases, I guess there's also increasing chance
of electronic failure having happened, as in the OP's case.

The 10 year batteries are lithium (but usually not changable).
You can buy lithium PP3's to put in any PP3 battery model.

I've never seen the point in the alarms with fixed batteries, unless it is
to prevent people taking the batteries out because of nuisance alarms. If
that is the case, they'll simply throw the whole thing away or pull
connections out!

Our alarms have replaceable batteries, a simple button test and if the
battery gets low, the alarm starts beeping at irregular intervals -
although it can take a few days to work out what's beeping, as they are so
infrequent and we have many other things, including children's toys that
beep.


SteveW

That is fine for you and me, but there are a significant number of people
who will remove batteries when they go flat and do not replace them, they
will also remove batteries for kids toys and not replace them or they cannot
afford to replace the batteries when needed.

Adam

On Sun, 16 May 2010 14:39:53 +0100, ARWadsworth wrote:

I am surprised there were any scorchmarks due to the very small current
that is used.

A few watts in a place that isn't supposed to have any disipation
will "age" that place quite quickly. You only need 4mA @ 240v to
dissipate 1W.

--
Cheers
Dave.

On Sun, 16 May 2010 12:09:39 +0000 (UTC), Andrew Gabriel wrote:

In article ,
Steve Walker writes:

I've never seen the point in the alarms with fixed batteries, unless it is
to prevent people taking the batteries out because of nuisance alarms. If
that is the case, they'll simply throw the whole thing away or pull
connections out!

It's because research shows a significant proportion of battery
alarms never get the battery replaced, so after the first year,
they sit there disabled.

Our alarms have replaceable batteries, a simple button test and if the
battery gets low, the alarm starts beeping at irregular intervals -
although it can take a few days to work out what's beeping, as they are so
infrequent and we have many other things, including children's toys that
beep.

Mine are all PP3 replaceable battary types, but they all have a
PP3-sized module in them which powers them from the 12V burglar
alarm, and generates a signal back to the alarm when they start
drawing enough power for the sounder. So I never have to change
any smoke detector batteries.

When I put some in my parents' home, I fitted them with the
lithum (10 year) PP3s, so we don't have to arse around with
battery changing. Since then, they've had an extention and also
have mains interlinked ones, but I didn't bother removing the
battery ones.

Yes, but the end result is that if they're doing anything which keeps
falsely triggering the alarm, they'll throw probably take the whole alarm
down and never put it back. At least with the removeable battery type, I
can whip the battery out and leave the cover hanging down to remind me to
put it back when I'm done!

SteveW

On Mon, 17 May 2010 21:31:06 +0100, Steve Walker wrote:

Yes, but the end result is that if they're doing anything which keeps
falsely triggering the alarm, they'll throw probably take the whole
alarm down and never put it back. At least with the removeable battery
type, I can whip the battery out and leave the cover hanging down to
remind me to put it back when I'm done!

Aye, and sensible removable battery ones don't allow the cover to
clip back in place unless there is a battery fitted.

--
Cheers
Dave.