On 01/11/2013 19:58, Chris Hogg wrote:
On Fri, 01 Nov 2013 19:18:40 +0000, Chris Hogg wrote:

On Fri, 01 Nov 2013 17:07:11 GMT, DerbyBorn
wrote:

Any ideas on how to do a real functional test? I want to show a neighbour
that both of hers are working and have similar sensitivities. I won't want
to buy anything.

Car exhaust has a significant CO content. Hold a large bin-bag over
the exhaust pipe of a car until the bag is full, then deflate it close
to the alarm. A repeat of the process should collect a similar
concentration of CO if the car engine is warm.

But ISTR that some CO alarms have a significant delay built in before
they go off. That was certainly the case twenty or so years ago, but
modern ones may have an instant response.

But I've just remembered that modern cars are fitted with catalytic
converters that are supposed to reduce or eliminate the CO content of
the exhaust, so find yourself an old car without one, or the exhaust
from a petrol mower or strimmer might do.


Then buy a new alarm in case the other pollutants have wrecked the sensor.