I have a Nighthawk carbon monoxide detector, 900-0089 (based on
KN-COPP-B mechanism).

Supposedly, this has a seven-year lifespan. What wears out?

Daniele

On Sun, 16 Sep 2012 16:37:53 +0100,
(D.M. Procida) wrote:

I have a Nighthawk carbon monoxide detector, 900-0089 (based on
KN-COPP-B mechanism).

Supposedly, this has a seven-year lifespan. What wears out?

The sensor. There are two general types,colourimetric detectors rely
upon the change in colour of a chemical similar to that used in the
simple paper strip or blob detectors.

Electronic detectors use a platinum or tin sponge (similar to
flammable gas detectors) or an electrolytic detector.

In all cases other gasses in the air eventually degrade the sensor so
it becomes less responsive (or in the case of colourimetric sensor it
triggers).

Some units solve the problem by making the battery a sealed
no-replaceable part. The battery life is 6-7 years and when it fails
you have to replace the whole unit making sure you get a fresh sensor
as well.

There is good article on the common electrochemical sensor at
http://www.coleparmer.co.uk/TechLibraryArticle/1192

On Sun, 16 Sep 2012 18:12:10 +0100, Peter Parry wrote:

On Sun, 16 Sep 2012 16:37:53 +0100,
(D.M. Procida) wrote:

I have a Nighthawk carbon monoxide detector, 900-0089 (based on
KN-COPP-B mechanism).

Supposedly, this has a seven-year lifespan. What wears out?

The sensor. There are two general types,colourimetric detectors rely
upon the change in colour of a chemical similar to that used in the
simple paper strip or blob detectors.

Electronic detectors use a platinum or tin sponge (similar to flammable
gas detectors) or an electrolytic detector.

In all cases other gasses in the air eventually degrade the sensor so it
becomes less responsive (or in the case of colourimetric sensor it
triggers).

Some units solve the problem by making the battery a sealed
no-replaceable part. The battery life is 6-7 years and when it fails
you have to replace the whole unit making sure you get a fresh sensor as
well.

Our unit starts a timer when you first power it up. Allegedly it will put
up a message on its screen (and stop working) after 7 years.



--
Use the BIG mirror service in the UK:
http://www.mirrorservice.org

*lightning protection* - a w_tom conductor

Peter Parry wrote:

On Sun, 16 Sep 2012 16:37:53 +0100,
(D.M. Procida) wrote:

I have a Nighthawk carbon monoxide detector, 900-0089 (based on
KN-COPP-B mechanism).

Supposedly, this has a seven-year lifespan. What wears out?

The sensor. There are two general types,colourimetric detectors rely
upon the change in colour of a chemical similar to that used in the
simple paper strip or blob detectors.

Electronic detectors use a platinum or tin sponge (similar to
flammable gas detectors) or an electrolytic detector.

In all cases other gasses in the air eventually degrade the sensor so
it becomes less responsive (or in the case of colourimetric sensor it
triggers).

So I presume it's not actually possible to test whether it's working
satisfactorily well or not, without getting a cowboy builder to mess up
your boiler for you.

Daniele

On Sun, 16 Sep 2012 21:42:28 +0100,
(D.M. Procida) wrote:

So I presume it's not actually possible to test whether it's working
satisfactorily well or not, without getting a cowboy builder to mess up
your boiler for you.

With your car engine cold (so the catalytic converter is not working)
put a binsack over your car's exhaust, fill it and place the CO
detector inside. If it doesn't go off in a minute it is certainly
dead.

You can also buy test sprays such as
http://www.safelincs.co.uk/detectaga...tector-tester/ but I'm not
sure they are any better than the binbag method.

Peter Parry wrote:

On Sun, 16 Sep 2012 21:42:28 +0100,
(D.M. Procida) wrote:

So I presume it's not actually possible to test whether it's working
satisfactorily well or not, without getting a cowboy builder to mess up
your boiler for you.

With your car engine cold (so the catalytic converter is not working)
put a binsack over your car's exhaust, fill it and place the CO
detector inside. If it doesn't go off in a minute it is certainly
dead.

You can also buy test sprays such as
http://www.safelincs.co.uk/detectaga...tector-tester/ but I'm not
sure they are any better than the binbag method.

And that's not going to help much if the thing's going to stop working
effectively sometime in the near future anyway. One would prefer to know
that it's going to be working until the next test.

Daniele

Peter Parry wrote:
With your car engine cold (so the catalytic converter is not working)
put a binsack over your car's exhaust, fill it and place the CO
detector inside. If it doesn't go off in a minute it is certainly
dead.

If it's a colourimetric detector, won't that poison the sensor? In other
words, if you test one of those coloured spots with CO and make it go black,
won't it stay black after the event? They wouldn't be much use otherwise -
it's not like you check them every 5 minutes.

Theo

On Sunday, 16 September 2012 16:37:55 UTC+1, D.M. Procida wrote:
Supposedly, this has a seven-year lifespan. What wears out?

If it's a sophisticated one, the lifetime expiry chip. They self-disable based on date.

In general, it's the sensor itself. These do have a limited lifetime. They're worn out by simple exposure to air, but particularly by a few compounds to which they're sensitive. Ammonia is one, so if you have sprogs and nappies, don't keep the CO monitor next to them.

Bob Eager wrote:
Our unit starts a timer when you first power it up. Allegedly it will put
up a message on its screen (and stop working) after 7 years.

Ours claims it will give a beep every 30 seconds when the time is up. But
that's also the code for 'flat battery'. Changed the battery this afternoon
(installed 2008, unit expires 2016) and it beeped for quite a while - even
when I took it out in the garden. Eventually it settled down into
flashing-the-green-LED-every-30s which is the normal working state, so I
/assume/ it's working...

There's some nice red flags that pop out when you take the batteries out,
preventing the lid going on, which at least mean you can't install it
without any batteries inside.

Theo

Peter Parry wrote:
On Sun, 16 Sep 2012 21:42:28 +0100,
(D.M. Procida) wrote:

So I presume it's not actually possible to test whether it's working
satisfactorily well or not, without getting a cowboy builder to mess up
your boiler for you.

With your car engine cold (so the catalytic converter is not working)
put a binsack over your car's exhaust,

unlikely to work as modern cars burn the CO in the catlayst



--
Ineptocracy

(in-ep-toc-ra-cy) €“ a system of government where the least capable to
lead are elected by the least capable of producing, and where the
members of society least likely to sustain themselves or succeed, are
rewarded with goods and services paid for by the confiscated wealth of a
diminishing number of producers.

In message , The Natural Philosopher
writes
Peter Parry wrote:
On Sun, 16 Sep 2012 21:42:28 +0100,
(D.M. Procida) wrote:

So I presume it's not actually possible to test whether it's working
satisfactorily well or not, without getting a cowboy builder to mess up
your boiler for you.
With your car engine cold (so the catalytic converter is not
working)
put a binsack over your car's exhaust,

unlikely to work as modern cars burn the CO in the catlayst

Not until they warm up though

--
geoff

On Sun, 16 Sep 2012 23:09:51 +0100, The Natural Philosopher wrote:

Peter Parry wrote:
On Sun, 16 Sep 2012 21:42:28 +0100,
(D.M. Procida) wrote:

So I presume it's not actually possible to test whether it's working
satisfactorily well or not, without getting a cowboy builder to mess
up your boiler for you.

With your car engine cold (so the catalytic converter is not working)
put a binsack over your car's exhaust,

unlikely to work as modern cars burn the CO in the catlayst

Read what he said.



--
Use the BIG mirror service in the UK:
http://www.mirrorservice.org

*lightning protection* - a w_tom conductor

"Peter Parry" wrote in message
...
On Sun, 16 Sep 2012 21:42:28 +0100,
(D.M. Procida) wrote:

So I presume it's not actually possible to test whether it's working
satisfactorily well or not, without getting a cowboy builder to mess up
your boiler for you.

With your car engine cold (so the catalytic converter is not working)
put a binsack over your car's exhaust, fill it and place the CO
detector inside. If it doesn't go off in a minute it is certainly
dead.

Is that the equivalent of dropping it into a bucket of water?
It doesn't tell you if it was working but you need a new one after the test.

On Mon, 17 Sep 2012 19:11:40 +0100, "dennis@home"
wrote:


With your car engine cold (so the catalytic converter is not working)
put a binsack over your car's exhaust, fill it and place the CO
detector inside. If it doesn't go off in a minute it is certainly
dead.

Is that the equivalent of dropping it into a bucket of water?
It doesn't tell you if it was working but you need a new one after the test.

No, it should be fine afterwards unless it is one of the quite rare
colourimetric detector. The detector is poisoned not by CO but other
pollutants in the air, especially silicone polish sprays for the
platinum sponge sort.

"Peter Parry" wrote in message
...
On Mon, 17 Sep 2012 19:11:40 +0100, "dennis@home"
wrote:


With your car engine cold (so the catalytic converter is not working)
put a binsack over your car's exhaust, fill it and place the CO
detector inside. If it doesn't go off in a minute it is certainly
dead.

Is that the equivalent of dropping it into a bucket of water?
It doesn't tell you if it was working but you need a new one after the
test.

No, it should be fine afterwards unless it is one of the quite rare
colourimetric detector. The detector is poisoned not by CO but other
pollutants in the air, especially silicone polish sprays for the
platinum sponge sort.

Not by the unburnt fuel?