Testing a CO alarm

[Lobster]

We have a fairly old CO alarm which has never gone off (well, it shouldn't, should it!?) and self-tests fine when you press the button on the front.

Does that necessarily mean it's working fine as regards measuring CO levels though? I don't see how...

I suppose more for interest's sake, I was wondering about setting up a test - short of firing up the barbeque in a closed garage, can anybody suggest an easy way to see if it does actually respond to increased CO levels? Obviously not possible to do any sort of calibrated check without the necessary equipment.

David

[Jonathan]

Hold a lit candle under it?

Jonathan

[Bob Eager]

How old is it? They usually have an expiry date, although at least some will warn you when that is reached. If it's near it, you might as well just get a new one!

[Lobster]

Hmm, just tried shutting in in a biscuit tin with a lit candle until the latter was suffocated (yes, I'm bored).

No alarm. Should there have been?

Discuss...!

David

[Andy Dingley]

AIUI, current production alarms attempt to detect sensor end-of-life and raise a warning then anyway. However I would follow manufacturer's lifetime guidance (usually 5 or 6 years, not long). The colour-change disks only last a year.

Easiest portable CO source I've found is a lump of barbecue charcoal in a tin. However this just checks function and doesn't give much faith in calibration.

[Lobster]

Ooh, so it does! Let's just say it expired, ahem, a while ago. Will certainly replace it, though am still interested in the original query!

Thanks David

[Peter Parry]

Unlike smoke detectors, CO sensors in the alarms have a very limited life - often no more than 2 years, newer ones can be up to 5 years. The self test does not test the sensor.

[Bob Eager]

BTW, let's hope they get the postal strike called off for tomorrow, and you might then get my parcel before the weekend...

[Lobster]

Indeed, looking forward to it - and fiddling about with a laserjet fuser should be more productive use of my time than pratting about with an old CO monitor! Thanks again...

David

[Lobster]

Good idea - we'll be laying a fire tonight anyway, so will find a lump of charcoal to burn and stick it in my biscuit tin. Sounds highly likely that the sensor's gone anyway but am interested to try it!

David

[Peter Scott]

Get a smoker to breathe on it?

Peter Scott

[crb]

BES sell an aerosol for testing CO alarms (Detectagas, P/N 12556). Around =A37.

CRB

[Dave Plowman (News)]

I tried the same with the wideband O2 sensor I was about to fit to the old car - nothing. The way you do a rough check they're working is by squirting some butane into them. The reading then goes off the scale.

[Al]

This was discussed on this group a while ago. I think the suggested solution was leave it in a garage with a car engine running. But then there were a lot of retards posting on that thread.

I dare say Google Groups will unearth this gem of a thread if you look hard enough ;-)

Al.

p.s. Just Buy A New One You Tightwad ;-)

[Usenet Nutter]

The Postal strike has been called off until after New Year

[Dave Plowman (News)]

Would have to be an old car. Modern ones have catalytic convertors - and one of their functions is to convert CO.

[pete]

The same question pertains to a new one. If yo're going to trust your life to a CO detector (even a new, shop-bought one), it would be nice to have confidence that the detector actually works. I'ts not as if you could take it back for a replacement if you're dead :-)

[dennis]

CO2 will also kill you. It just doesn't poison the blood the same way.

[Simon C.]

IIRC the sensor can be permanently damaged by exposure to high levels of CO. Perhaps the 'test aerosol' suggested earlier would be best.