Dtecetor and Sounders in conventional and addressable systems

[abdi]

Hi, I am recent fire alarm engineer, and I need some answers for the following questions.

My First question is, say you got an addressble system, with 1 loop, all the
detector heads are ok, but the panel shows that some where in the cable
there has been breakage but the panel will not tell you where. So how do you
quickly locate where the problem is.

2:In conventionl system you got sounder fault in say sounder circuit 1. So you check for open circuit and short circuit, you find that the end of line resistor is connected, howevere one of the sounders has a loose wire which makes the circuit open. my question is how quickly do you identify which sounder is the faulty one? The way I would do it is test all the bells and see the one thats not sounding. is that the quickest way?

3:Same question for the detectors?

Please email me with the answers to my questions to this email address:

Furre@aol.com

[Graeme]

1) Some panels can tell you exactly where the break in the loop is but if not the easiest way is to do the following.

Remove the return cable from the loop card,creating a radial circuit.
Install a link between the positive send and return.Same for neg.
reset panel.
If the open circuit in the panel is not intermittent,all the devices after the break will now show communications faults(device missing).
There are other factors which can cause the panel to display loop open circuit fault .I have had a faulty device cause one.
If the break is intermittent it is more difficult but try this first.

2) If the loose connection is stopping you recording the eol resistor then yes turn on the sounders and see where they stop working.If the loose connection is making and breaking then you will have to check every sounders connections are tight.

With detectors in open circuit fault on zone,test each one in order(presuming you have drawings with cable routes)  to see where they stop working.
Or again inspect every detector.

You should famiarise yourself with how addressable and non addressable systems work to enable you to fault find.
I.e the addressable system will only send voltage one way in normal conditions.In open circuit it will drive voltage both ways send and return,so minimal detction is lost on loop.
If you have an open circuit fault with say 20 devices missing,the chances are that there is a short on the loop and the isolators have kicked in.The isolators have amber leds to show they are active.The fault will be in between the two isolators.

good luck

[Allen Higginson]

You may also have an internal problem with a sounder which stops the panel seeing the EOL but where all the sounders still work.In this case it REALLY helps to know which way your circuit runs so that you can break it down to id which sounder is stuffed (thats a local technical term for malfunctioning).

[Graeme]

Funny i had that last month for the first ever time.A Roshni sounder causing a fault.
Easiest way for that is to locate the eol and instal in a sounder about half way down the line.If the fault clears it's on the out to the next lot.

Ignore Buzzard's terminology for faulty.He has been on the tools longer than me and it must be turning him mad.
Correct word is knackered.

[Allen Higginson]

Funny enough it was a Roshni here as well!
Less of the old man stuff - at least I can spell "turning" correctly!

[Graeme]

picky.

[abdi]

thanks very much fellas, I will if course come back with many more technical question in the near future, I just hope you guys are still alive..........


only joking, please ignore my light hearted joke if it offends you.

Once again thanks to Graem Miller and Buzzer, I hope I spelled your user name correctly..

Catch you again soon.

Regards
Abdi

[Allen Higginson]

No worries!

[Graeme]

it's okay.I'm a bit younger so should be of this earth a while.
Your are welcome, nope you did not spell our user names correctly but i think Buzzer is quite good though.

[Allen Higginson]

Wouldn't bet on it!