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Troubleshooting false smoke detector alarms?

B

blueman

Jan 1, 1970
0
Last night we had two false smoke alarms signaled from the same 3rd
floor stairwell sensor. There was definitively no smoke, heat, or
other environmental changes in the area.

The sensor is an ESL 12-24V 4W Smoke Detector w/ Heat. It is wired
together with a relay (The panel is a DMP XR200L 10-242).

The alarm was professionally installed about 4.5 years ago.

What are the likely causes of such repeat false alarms and how would
one go about troubleshooting and verifying them?

What is most likely - faulty sensor? dirty sensor? faulty relay? loose
wiring? other?

Thanks
 
J

JoeRaisin

Jan 1, 1970
0
blueman said:
Last night we had two false smoke alarms signaled from the same 3rd
floor stairwell sensor. There was definitively no smoke, heat, or
other environmental changes in the area.

The sensor is an ESL 12-24V 4W Smoke Detector w/ Heat. It is wired
together with a relay (The panel is a DMP XR200L 10-242).

The alarm was professionally installed about 4.5 years ago.

What are the likely causes of such repeat false alarms and how would
one go about troubleshooting and verifying them?

What is most likely - faulty sensor? dirty sensor? faulty relay? loose
wiring? other?

Thanks

First thing I would suspect is a dirty detector.

Take apart the smoke chamber and clean it. They should be cleaned
regularly anyway.

You say it was professionally installed but when was the last time you
had the system PM'd by a professional? Fire systems, especially in
places where people sleep, need to have preventive maintenance performed
on a regular basis.

It is a pretty simple procedure and you can often get a reasonable rate
if you sign a contract for annual tests. The technician will test the
back-up battery, ensure wire integrity, check the sensitivity of the
detectors, test and clean them and verify proper operation of all system
components to include to notification appliances.

This will help avoid false alarms, but more importantly the system is
more likely to work when it is needed and get the people out.

The only thing worse than no protection at all, is protection that
doesn't work. Remember, it only takes one night without working
protection...
 
B

blueman

Jan 1, 1970
0
JoeRaisin said:
First thing I would suspect is a dirty detector.

Take apart the smoke chamber and clean it. They should be cleaned
regularly anyway.
Just did it -- took apart and cleaned out the optical chamber with
compressed air and gently swabbed the LED with a clean fine brush -- I
will see what happens.
You say it was professionally installed but when was the last time you
had the system PM'd by a professional? Fire systems, especially in
places where people sleep, need to have preventive maintenance
performed on a regular basis.

It is a pretty simple procedure and you can often get a reasonable
rate if you sign a contract for annual tests. The technician will
test the back-up battery, ensure wire integrity, check the sensitivity
of the detectors, test and clean them and verify proper operation of
all system components to include to notification appliances.
They come by for a "wellness" visit every year. I also am pretty
intimately familiar with most of my system but I have been lax in
getting around to taking apart and cleaning our 14 smoke detectors
(code required that number!)
This will help avoid false alarms, but more importantly the system is
more likely to work when it is needed and get the people out.

The only thing worse than no protection at all, is protection that
doesn't work. Remember, it only takes one night without working
protection...

You are absolutely right.
 
M

Matt Ion

Jan 1, 1970
0
JoeRaisin said:
First thing I would suspect is a dirty detector.

Take apart the smoke chamber and clean it. They should be cleaned
regularly anyway.


I'll second that - I had one site where the drywall dust stirred up from
construction was causing a detector to go off constantly... the
construction crew just ripped the thing down... *sigh*
 
S

Steven Vaughan

Jan 1, 1970
0
blueman said:
Last night we had two false smoke alarms signaled from the same 3rd
floor stairwell sensor. There was definitively no smoke, heat, or
other environmental changes in the area.

The sensor is an ESL 12-24V 4W Smoke Detector w/ Heat. It is wired
together with a relay (The panel is a DMP XR200L 10-242).

The alarm was professionally installed about 4.5 years ago.

What are the likely causes of such repeat false alarms and how would
one go about troubleshooting and verifying them?

What is most likely - faulty sensor? dirty sensor? faulty relay? loose
wiring? other?

Thanks



- A few possibilities:
Dust buildup
Drywall dust
installed too close to a bathroom door (shower steam)
cleaning products or insecticide sprayed close to the detector
loose wiring
insect(s) in the detector or on the connectors
rodents chewing on wiring
flaky EOL relay
voltage fluctuation
faulty detector
 
B

blueman

Jan 1, 1970
0
Steven Vaughan said:
- A few possibilities:
Dust buildup
Drywall dust
installed too close to a bathroom door (shower steam)
cleaning products or insecticide sprayed close to the detector
loose wiring
insect(s) in the detector or on the connectors
rodents chewing on wiring
flaky EOL relay
voltage fluctuation
faulty detector

Thanks to everybody for the input.
I cleaned out the optical chamber (per the manual) and so far no alarm
signal after 36 hours.

Everything else looks good on physical inspection but if the cleaning
doesn't hold then I will suspect either the device or the EOL relay
since I think I can rule out the other potential causes.
 
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