Fire alarm fault

[moosey86]

I'm in a bit of a situation I could really do with a bit of guidance on sorting out a fault on a fire alarm in a pub.

I thought I'd sorted it last night when they showed me the old lath and plaster ceiling had collapsed in one the rooms and I couldn't even twist the smoke head off indicating to me that the thing was probably filled with dust and grit probably causing it to nuisance trip.

Turns out it's gone off again. I'm not a fire alarm engineer so the methodical ways of tackling it are not firmly installed into my know how.

It's a conventional system with about 8 - 10 smoke heads and 3 call points and it's not coming up with a fault it's just being set off some how....what is the most methodical way of getting to the bottom of it without me chasing my tail for hours on end?

 

[moosey86]

My bad, I've just been told its coming up as general fault on zone 3. So it's not nuisance tripping and setting the alarm off it's just setting off the buzz alarm from the panel.

 

[Fast&Rough]

Smash it off the ceiling with a high velocity impact tool and put a new one up

 

[moosey86]

Yea cheers mate that's a lot of help :/ but I've already taken that down and bypassed it so its not that smoke head that's causing the fault it's something else

 

[tazz]

Zone faults are either open circuit or short circuit.
99% of faults are open circuirt, Only real way here is to take each detector off in turn and measure the "in " voltage on the base. When you come accross one with no "in " voltage, then the fault is between the last one test and the detector you now on. Also the last detector will have a end on line unit or resistor, make sure all terminals are secure.

 

[MDJ]

to add to tazz's post, I can only say a loose head can cause a fault and is a very common fault as well, double and treble check the heads are on properly.

 

[moosey86]

I went there earlier and swapped zone 3 for the empty zone 4 slot to see if it's a wiring fault or the panel.....just gona wait till the customer phones me again now....I've told him to make sure he takes note of exactly what the panel says in fault mode because both times I've got there the fault has cleared as its intermittent.

But your advice has been massively helpful and will speed the process up if I need to go into it further.

Cheers guys

 

[tazz]

Sensible idea, as could this could prove a panel fault, so next 24hours or so will provide more info

 

[Deleted member 26818]

You say you removed the smoke head and bypassed it.
How exactly did you do this?
It may be that you need to fit an end of line resistor in place of the smoke head.

 

[tazz]

Then it wouldnt be intermittent, so im sure we talking looped out

 

[moosey86]

It wasn't the end of line smoke, I just disconnected it and put the incoming and outgoing cables into a jb and joined it as if it was a continuous circuit

 

[Englishsparks]

Could be a fault on cable or detector.
Move the end of line device to approx the half way point in the zone, this will atleast tell you wich half the fault is in.
Then move to the half way point in the faulty half narrowing the fault down to between points.
Hope this helps but there is no easy way of finding the fault, very time consuming and a ball ache but is the only way.

 

[chrish_1977]

Had a similar problem with the job I was on, the plasterer had decided that my cables were in the way of his screws, just did continuity between points starting at panel to to find where the faulty cables were, pulled in new legs where required, all good now

 

[ayjay]

hope u fitted the spare zone 3 panel terminals with a resistor

 

[moosey86]

Nah, I left it open circuit, shut the door and walked away as the buzz alarm was going mental. Just thought it was normal