12v smoke, heat and CO alarms, with volt free contacts

[Sparks]

Do they all exist somewhere!?

I would like to install some smoke,heat and CO alarms in the house, powered from the alarm supply, and connected to the alarm.

I can find simple smoke alarms that will do this,

not heat (kitchen) or CO alarms that are 12v and have contacts for the house alarm.

Any pointers?

Ta

[SantaUK]

I'll need to check my catalouge, but you can get a "normal" fire alarm base unit that has relay contacts on it, and can put any of the heads, smoke, heat or CO2 onto it. I can't recall the name but I will find out.

[ARWadsworth]

is no CO detector though

Adam

[Andrew Gabriel]

The following small circuit board replaces a PP3 battery in a smoke detector to provide for 12V operation with relay contacts.

would probably not meet any BS requirements, if your system is required to do so. Also, make sure you test the detectors using the sensor after installation, not just the test button. They don't work reliably with the common rectangular EI smoke alarms (they do with the test button, but not with a real detector triggered alarm). Obviously, there's no interlinking, so you are dependant on sounders driven by the burglar alarm, rather than other smoke detectors generating additional alarm indications.

I used a number of these in my house a few years back. The picture would imply the design is changed since I bought them -- mine have PP3 battery tabs soldered onto the board, and a changeover relay, and a jumper to select if the relay should lock on (reset by power interruption) or switch off when the alarm switches off.

Another option is a 12V smoke detector (optical in this case) with contacts but no internal sounder:

[Sparks]

Thanks, that would be appreciated :-)

Sparks...

[timothy.w.oleary]

Heat detectors do not require any power in order to operate. Just a pair of wires back to the appropriate hard-wired zone terminals in the panel. They are N.O. (normally open) devices; that is, they have outputs which are open cicuit until actuated, then the circuit closes. The alarm panel would hopefully call for the use of end-of-line resisters on the zone loop wiring, and would accept either a closed loop sensor or an open loop sensor. The wiring of an open loop sensor would be slightly different than for a closed loop sensor.

You would also need to ascertain if your panel is able to produice an alarm condition upon either an open circuit or a closed circuit with the end-of-line resister wired in the loop. Since I do not know what systems are used across the pond, I cannot make any assumptions about what y'all have. Some panels will treat an open as a 'trouble' condition and not produce an alarm condition.

CO detectors are another story. The technology for those is totally different than that required for a smoke detector, and the demand for them has been limited. PAMA has offered a unit for several years that will work off of 12VDC which is what the typical burg panel has. General Electric Security is advertising one in the trades, but I haven't seen one yet. Kidde also offers several types. Marcuro is another brand I know of..

Similarly there is not a great selection of battery operated CO's that have a "dry contact output" which is what you would use to connect a detector to a hard-wired alarm panel, or use in conjunction with a supervised wireless transmitter if you ware wanting to add a CO detector to a professional wireless alarm system. Most CO detectors are stand alone, and have integral audible sounders. It is unlikely that you would want the fire department to respond if you had excessive CO in your premises. So why would you want to connect it to the alarm panel? Of course I could imagine several scenarios: you're hearing impaired, it's a large struture and you might not hear the alarm if it were to go off; it's a summer cottage, and you just want to be notified. All good reasons. Changing batteries is a pain in the butt so you'd like to power it off a constant voltage source. Whatever the reason "The customer is always right"

BTW why do they call you 'sparks?'

email me of you need more > > I'll need to check my catalouge, but you can get a "normal" fire alarm