Cycling UK Forum

I came home y'day to find one of the co alarms bleating piteously. Its built-in - that is, non-replaceable - battery has died. Given that my modern-build flat has no gas appliances other than the boiler, which is in its own cupboard, can you, dear reader, help me understand why there's one screwed to the ceiling of every room but not in the boiler's cupboard...

The detectors are there to protect people. People live in the rooms rather than the cupboard.

Jonathan

You might easily think that the earlier the warning, the better. If so, an alarm close to the likely source of the danger might give the best warning, so long at it was audible throughout the building - possibly a sensor over the boiler with remote sounders/flashers

This says place a detector outside the door of each bedroom.

I had a detector that said it should be sited close to the floor because CO is heavier than air, but it seems that CO & air are almost identical density, so when combustion products are hot there's a slight advantage to mounting on the ceiling.

In a block of flats CO could creap into your flat from a faulty boiler elsewhere. CO detectors are usually fitted at head height, so may be lower in bedrooms.
Read the installation instructions carefully before you fit a replacement. You can get ones which plug into a spare 13 amp socket.

I live close to an electrician who clears out his garage every 6 months of stuff he's removed from premises. I spotted a new boxed identical smoke detector to mine. Took it home and then noticed it had a use by date on it which had expired. I then checked mine and saw that they had expired 6 years previously. They are mains powered with a PP3 battery backup. I hoovered the dust out of mine and lit a match beneath to check it was still working. Phew so probably good for a little longer as the radioactive americium detector has a half life of 240 years.

Yes, you might detect a fault in the boiler earlier with a local sensor. It might need a different threshold.

But you'd still need detectors in or near the rooms because carbon monoxide can come from other sources including portable heaters (often used in the past because of fuel poverty) and other people's accommodation.

Edited: Crossed post.

Jonathan

My Fire Angel CO detectors are sold with a life of 10 years, but when I bought a new one I kept the old one out of curiosity to see how long it lasts. The battery and bleeper are still working after 22 years now, but according to that website I linked above, the gas detector life can be as little as 6 years.

We had a CO leak from our old boiler (dishwasher sized floor standing job). We were only alerted to it when we heard an unidentifiable bleeping in our living room. After an extensive search to locate the source, we realised that it was a CO monitor hidden in the back of a living room TV cabinet draw (given to us awhile back by my in-laws from their sold caravan). Our living room is a sizeable distance from the utility room housing the (now replaced) boiler.
I was surprised at how sensitive the monitor was and was grateful for it.
We now keep a (combined smoke &) CO monitor on each floor of the home.

Is it common knowledge that CO detectors have a limited life? At least mine did. A date after which the sensor needs replacing. Confess I didn't replace mine but I only ever switch the boiler on when I want a shower so it's 15 mins at a time during the day and not left on.

Ian

Official guidance in Scotland is that you need one in each room that has a carbon fuelled appliance or flue.

Psamathe wrote: ↑16 Jul 2022, 5:48pm Is it common knowledge that CO detectors have a limited life?

axel_knutt wrote: ↑16 Jul 2022, 2:37pm My Fire Angel CO detectors are sold with a life of 10 years

I was typing from memory, but I've just checked, and mines 7 years. It's a Fire Angel CO-9X.

Just bought the 2 new ones - £50 ! Still, cheaper than a funeral...

I think you’ve made a sensible choice.

I didn’t say in my original post, when I identified that the mysterious bleeping was a CO alarm I rushed to turn off the boiler and open windows & doors (& check on the kids). I had a throbbing headache for about 3 days and was quite flushed in the face for a day - classic symptoms of toxicity. I could have measured my carboxyhaemoglobin levels at work but was too scared to! If you understand what CO does to your body’s oxygen carriage (it’s 250 more potent at binding to your intrinsic oxygen carrier) you realise just what a killer it is. The end result is no different to cyanide poisoning ie starving the cells of oxygen albeit by slightly different mechanisms. I am highly suspicious that it has been used by some “special forces” in the past to disastrously manage certain high profile hostage situations.
Without the alarm, I shudder to think what might have happened. The cause of the CO leak was self induced - our utility room housing the boiler had 2 large wall vents in it which I covered up to keep the cold out!! Little did I know that the old floor standing boilers require a large internal oxygen draw to function properly, hence the reason for the vents. To add to “boiler hypoxia” we also had the open fire raging in the living room! Fortunately modern boilers draw their oxygen supply from the outside vent pipe for safety.

As you say: cheaper than a funeral!

audaxjk wrote: ↑17 Jul 2022, 2:15pm ...
The cause of the CO leak was self induced - our utility room housing the boiler had 2 large wall vents in it which I covered up to keep the cold out!! Little did I know that the old floor standing boilers require a large internal oxygen draw to function properly, hence the reason for the vents.
...

Yes, reducing ventilation is another common contributor along with faulty boilers and paraffin heaters. And interacts with other effects of fuel poverty.

And the effects are insidious: thanks for the reminder.

Jonathan

Second thoughts