Has anyone had these Smoke Detector Issues?
- Thread starter mn50racer
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Yet another annoying thread where the OP disappears and we don't know the outcome, if any.....
maybe the CO2 killed them all
Thank you for your input everyone. I have tried all avenues of diagnosising this problem that my customer is having. After discussing the issue with the manufacturer we tried a last resort of unpluging the power to the smoke detectors and letting them run on battery to see if the problem is wiring related. I recieved a call from my customer tonight that the upstairs detector is still going off at the exact same time every night for about 12 minutes. It has been going off every night at the same time. So I am convinced that it is a radio interference problem, but have no way of testing for that. The manufacturer's engineer's were not able to give me a possible frequency due to the fact that they have never heard of the problem. So I am at a dead end road with no answer for my customer. If anyone has a valid answer or a way to persue this further for me it would be greatly appreiciated.
K8MHZ
Senior Member
- Occupation
- Electrician
If it is RF the likely cause is an illegal CB operator. Ham radios are 'cleaner' and the people the use them know about interference and how to keep it under control.
If it is an RF problem I can help you but I will need more info and you may need to some different test equipment.
(I am an Extra Class Amateur Radio Operator)
PM me as we work through this and once we do we can post what we found here. In the mean time, ask your customer a few things, if you could.
1) Is there any other sign of RF problems beside the smokes. They will include voices or noise coming through computer speakers or telephones. They can cause touch lamps to cycle. They can disrupt the video on TVs.
2) How close to a commercial radio station is the customer?
3) Are there any 2 way antennas in the neighborhood visible?
4) Do any of the neighbors have vehicles with 2 way antennas on them? Especially a big one that looks like a spear with a huge open coil at the bottom.
Start looking around for some impromptu test equipment. Any 'walkie talkie' type radio. They operate on different bands, some are CB. The bigger in size the better as the CB band uses larger equipment. Any AM radio, especially portable. Any short wave receiver.
When and if we find there is an RF problem I can put you in touch with people skilled in locating it and taking care of it. Trust me, the FCC takes a dim view of any radio operation that interferes with any life safety equipment.
I can also locate licensed amateurs in your area by searching the FCC's database.
Back to you,
shepelec
Senior Member
- Location
- Palmer, MA
The only thing you have going for you is it happens at the same time every night.:-?
K8MHZ
Senior Member
- Occupation
- Electrician
That's more than I have had on some of my 'ghost busting' jobs!
At least there is a time frame in which to compare monitored values.
K8MHZ
Senior Member
- Occupation
- Electrician
RF or not RF?
RF or not RF?
One way to determine if RF is the issue is to get two identical cheap (the cheaper the better) smoke detectors. Fabricate a Faraday cage around one and not the other. Place them as close to the alarm that falses as possible. If two of the three alarms trip and the one in the cage does not, you indeed have an RF issue.
If they all trip, you may or may not have an RF issue, but it is more likely there is a particulate issue.
In that case, replace the Faraday cage with plastic wrap and make the same test. If the plastic wrapped alarm is the only one not tripping, there is an issue with the air being sensed.
I think the above is important to determine which 'fork in the road' to the solution needs to be taken. If we choose the RF 'fork', I can help zero in on the target after determining that there actually is one.
Of course, a DC to daylight spectrum analyzer would help! (Hint, rich (or single) ham radio operators have them built into their radios.)
RF or not RF?
One way to determine if RF is the issue is to get two identical cheap (the cheaper the better) smoke detectors. Fabricate a Faraday cage around one and not the other. Place them as close to the alarm that falses as possible. If two of the three alarms trip and the one in the cage does not, you indeed have an RF issue.
If they all trip, you may or may not have an RF issue, but it is more likely there is a particulate issue.
In that case, replace the Faraday cage with plastic wrap and make the same test. If the plastic wrapped alarm is the only one not tripping, there is an issue with the air being sensed.
I think the above is important to determine which 'fork in the road' to the solution needs to be taken. If we choose the RF 'fork', I can help zero in on the target after determining that there actually is one.
Of course, a DC to daylight spectrum analyzer would help! (Hint, rich (or single) ham radio operators have them built into their radios.)
K8MHZ
Senior Member
- Occupation
- Electrician
Note on the above:
The wiring to the smokes can act as an antenna. If battery only powered smokes don't trip, that may be an indication that there is RF being received through the wiring to the smoke detector that is going off.
A quick check would be to add a few random lengths of wire to the conductors, all three of them. This will change the resonant frequency of the conductors and make them less sensitive to the frequency of the RF being received.
A further note: Leaving the pigtails in is NOT a repair, it is a cover up. If there is sufficient RF in the residence to set off an alarm the source should be determined and evaluated. Such interference is a signal that something is wrong. Somewhere.
The wiring to the smokes can act as an antenna. If battery only powered smokes don't trip, that may be an indication that there is RF being received through the wiring to the smoke detector that is going off.
A quick check would be to add a few random lengths of wire to the conductors, all three of them. This will change the resonant frequency of the conductors and make them less sensitive to the frequency of the RF being received.
A further note: Leaving the pigtails in is NOT a repair, it is a cover up. If there is sufficient RF in the residence to set off an alarm the source should be determined and evaluated. Such interference is a signal that something is wrong. Somewhere.
Does your customer for sure know it's those detectors going off? I've seen it where a homeowner thought their smokes were going off, but it was actually the home alarm panel beeping because it was faulting every day at the same time. The panel was trying to conduct a daily system check and could not communicate with the central station so it chimed for a certain amount of time indicating a error. Just a thought.
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