Smoke detectors.

[VicS]

Anybody know what upsets them? One of mine has gone crazy. We triggered it while cooking lunch on Tuesday. Last night it went off a couple of times, once around 3 o'clock and again at about 6 o'clock. It went off while I was cooking my toast at breakfast time and again at lunch time. Its just gone off yet again! No wonder people take the batteries out. I'm afraid I've had to do the same.

The house is not on fire and its battery seems ok.

 

[nigelcarton]

You can buy them now with a 'hush' button. /forums/images/graemlins/ooo.gif

http://www.wickes.co.uk/invt/521012?htxt...J9bQPNXrg%3D%3D

 

[pau1gray]

Give it a good blast with the hoover and see if that helps

 

[Shannoner]

[ QUOTE ]
Anybody know what upsets them?

[/ QUOTE ]

Eh.......maybe smoke?


Does exactly what it says on the tin, cooking/frying on high heat or burning the toast = smoke = lots of noise from smoke detector.
Put the detector in the hallway and shut the kitchen door when cooking.
Works for me

 

[VicS]

[ QUOTE ]
maybe smoke

[/ QUOTE ] At half past midnight, 3 o'clock in the morning or 6 o'clock in the morning?
I'll try cleaning & tightening the battery contacts, cleaning the sensor as we had problems once before when a spider got into one of them and take a look for any dry solder joints. It may be time to invest in a new one.

 

[Bunny]

Vic have a look here .All free and some good advice as well.

 

[emnick]

If its an optical type the 'optics' can become dusty and hence a good vacuum through does the job.

 

[Anonymous]

Most domestic smoke detectors are unbelievably cheap (I used to work in the industry) and while I hate to suggest that an engineer such as yourself chucks things out if they can be fixed, this might be one of those occasions! Don't even try to fix an ionisation detector other then hoovering any obvious dust from the unit.

If it is an optical detector (if it is ionisation it will tell you that there is radioactive material in there) try hoovering the outside. If you can open up the chamber there is no harm in cleaning it. Use some meths, IPA or whatever you keep of that ilk and be sure to clean the LED emitter and receiver (may be the same device with a split down the middle). Test it with a paper taper afterwards.

 

[VicS]

It is the ionisation type. Contains 1.0 uCi (37 kBq) Americium 241, an alpha emitter plus some low energy gamma.
So I have cleaned and tightened the battery connections, re-soldered a few joints on the PCB, although none looked that doubtful, and at the moment it is sitting here quite happy and silent.

I've had the three of them for about 25yrs so it wont be big deal if I have to replace one of them. ( I bet Nigel Luther would have had a fix, or modified something else!)

Interesting to see in bunny's link that it is recommended that one has both types so perhaps I'll buy an optical one to replace it.

 

[Anonymous]

Well, as long as it's not silent when there is smoke, you should be fine /forums/images/graemlins/wink.gif As you probably know, the principle is very simple...the radioactive source ionises the air in the chamber so a small current can flow across the chamber. When smoke particles enter they absorb the ions and the current falls. The fall in current is detected and the alarm is raised. Over many years it is incredible what can happen inside the chambers - I have seen insect colonies!

I was thinking of Nigel the other day - I haven't been over to the other place, keep forgetting to, and I see that he has cancelled his user name here. Shame. Need not have happened.

 

[double_ender]

Appart from the detail of how they work, I think they can be useful in the boats engine compartment as an early warning of things getting burney hot.

A converted MFV on the west coast a few years ago had a fire in the engine room, basically in the wiring to start with, and it had been smouldering for some hours before it flamed up and was noticed, almost writing off the boat

 

[Anonymous]

Yes, that's right for ionisation detectors which detect invisible particles. BUT they are a bit prone to false alarms in an engine room environment and it is more usual to use thermal (rate of rise) or fixed temperature detectors in engine rooms. No harm in fitting an ionisation onto a zone that can be inhibited.

 

[Boathook]

Did the same with my new one. Cooking the bacon set it off. Now remove it for the duration of cooking. It's nice to know that it does work !!

 

[emnick]

Not sure if you are aware but most Fire & rescue services are not only giving them away but also installing them for FREE, this is not means tested and is there for ALL to take advantage of. Ask at your local firestation about HFSRA (Home Fire Safety Risk Assesments) The detectors used are the Fire Angel with a mute button and a 10 year battery life, really good detectors. No Excuse not to have AT LEAST one! PS Also provide special alarms for hard of hearing with a vibrating pad for under pillow once again FREE