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Hi all, I am not an electrician, I am a tenant in a building where a Twinflex fire alarm system is installed. I have seen a thread on the subject in this forum so I thought I would ask if you have any thoughts about the following matter.

For more than two weeks now we have been experiencing a strange issue related to zone fault detection: almost every day a fault is detected, always in the same zone (which covers five flats across two floors of the building -- so I believe seven detectors overall including two in the corridors).

When the fault is detected the control panel buzzer makes its noise and the amber light associated to a fault in that zone flashes, then we silence the buzzer (we don't reset the panel), then after a while the fault goes away by itself (the amber light is not shown anymore). Of course when the fault goes away also the setting silencing the buzzer is deactivated so in the following occurrence the fire alarm starts buzzing again and so on.

As I mentioned above it happens almost daily, usually between 6:30 and 8 in the morning during weekdays while later in the morning and in the evenings during the weekend. The fire alarm maintenance people state that the only explanation for this is that in one of the flats people are disconnecting the detector on purpose and then reconnecting it.

I agree that the pattern suggests some kind of human factor, but I find it unlikely because the people living in those flats have been there for a while and I have suddenly decided to deliberately regularly tamper with the detectors, and have decided to continue even after they have been contacted and warned. My hypothesis is that they are doing something ordinary and this is triggering the fault (for instance perhaps something along the lines of "perhaps there is a leak and when they shower this interferes with the system, while when they are done it goes back to normal"). The fire alarm maintenance people say that in this case the control panel would need to be reset, that the fault wouldn't go away by itself, but I am not sure how this can be ruled out entirely.

One issue of course is that since this tends to happen early in the morning or during the weekend and never lasts for too long, it's hard to get someone from the maintenance (and with the keys and with the due notice etc) to inspect the zone while a fault is in place so that the detector causing the fault can be identified.

I wonder if you people have any thoughts on this matter or similar experiences? Do you think it might be someone causing this unwittingly or do you think it is definitely due to something wrong being done deliberately? How would you go on to diagnose and fix this issue? Is there any way to silence the control panel fault buzzer long term (i.e. across several fault detections), of course in a way that doesn't damage the system and respects regulations?

Thanks for any contributions.
 
Not the best of control panels, and this type of fault is very common with Twinflex. The sensors have small connection pins which corrode or tarnish over the years giving no end of problems. Would suggest no human interference is going on, just movement or opening doors could course this.
Personally I would replace the entire system, will save money in the long run. This comment of 5 flats over 2 floors being on one zone is worrying, specially when trying to identify the location of a fire.
 
Thanks, this is precisely what I am concerned of, that because of their insistence on a deliberate human interference we might go on and on without ever really solving this.
 
I agree that the pattern suggests some kind of human factor, but I find it unlikely because the people living in those flats have been there for a while and I have suddenly decided to deliberately regularly tamper with the detectors, and have decided to continue even after they have been contacted and warned.

I see I can't edit my first post anymore, this should read "I agree that the pattern suggests some kind of human factor, but I find it unlikely to be wrongdoing because the people living in those flats have been there for a while and I doubt they have suddenly decided to deliberately regularly tamper with the detectors, and also continue to do so even after they have been contacted and warned."
 
Other things to check which I have come across with Twinflex systems:
Poor end of line signal, swapping the end of line detector with a new one, or with another on the system, then setting the EOL switches correct for their new locations can correct the problem

More than one detector set as EOL

Dust on the optical sensors/in the optical chamber causes all sorts of random problems, from fault indication to random false alarms.

Cable screens not connected can also cause problems from electrical interference.
 
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Thanks all, it seems that the issue was due to a light being recently fit in one of the flats too close to a detector...
 

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Twinflex Fire Alarm Zone Fault Comes And Goes
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Security Alarms, Door Entry and CCTV (Public)
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