I have 10 motion detectors on my system. On the top floor I have one in the bedroom, one in the garage, and four in the living area. The four in the living area are approximately 100ft apart, and face each other with a sight offset. When I initially installed them, everything appeared to work fine. The four that face each other with an offset started going off every 2-10 minutes. I switched the internal protions of the detectors with the same detectors from the basement, and the experience the same problem. No false alarms in the basement , but all four upstairs still experiencing false alarms. I replaced one of them with a Bosh alarm, and the flase alarms stopped on that one detector. I replaced another one with a new DT-7450, and it still false alarmed. I replaced a third with an older detector, and the false alarms stopped on that one as well. What envionmental factor (or flaw in the wiring) would cause the DT-7450's to false alarm, while the Bosh, and another dectors work fine? Any help would be greatly appreciated.
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Honeywell DT-7450 motion detector problem
- Thread starter Bubbba
- Start date
I should add that all detectors on this system are wired to supervise on open, and as interior or interior followers. The tampers are wired to separate input zones. Any ideas on what would cause the detectors to false alarm every two to ten minutes like this? One is close to an intake vent - which shouldn't cause any issues, and hasn't for the other detector that was there for years. There are no exterior lights from cars, the windows are not open. No animals, insects, etc.... The frequency of the alarm would indicate (I believe) that it's likely some electormagnetic interference, I just cant imagine what that would be....
That's a good point. I have set them to the hightest sensitivity (as I did with th bosh and another older detector that don't experience false alarms). I'll reduce the sensitivity and see if there is any correlation to the false alarms. If they are alarming based on the mircrowave only (without any infrared input) would that indicate they're malfunctioning? I'm asking that only because the other two motion detectors (Bosh and an older one) work fine.
No, but if the passive portion was/is marginal for an alarm, the MW tripping on top of it causes the "verified" response for both technologies, the detector will generate an alarm.
I'm willing to bet the older detector and the Bosch unit are operating on different frequencies compared to the suspect units.
Microwave portions of dualtecs should always be set to the minimum range and sensitivity to generate an alarm within their coverage patterns, and in actuality, their coverage, since they can see through walls and glass, should be set for barely tripping on the edge of the PIR coverage.
I'm willing to bet the older detector and the Bosch unit are operating on different frequencies compared to the suspect units.
Microwave portions of dualtecs should always be set to the minimum range and sensitivity to generate an alarm within their coverage patterns, and in actuality, their coverage, since they can see through walls and glass, should be set for barely tripping on the edge of the PIR coverage.
That they are the same frequency and consequently may interfer with each other causing false alarms does seem like a possibility. But I reduced the sensitiviy levels and they made no difference. I also reviewed the elk log on these motion detectors and found the following:
1. They did not start false alarming for about a week after installation. The false alarmed for about a week, stopped for about 48 hours and then started again.
2. One and only one DT-7450 motion dectector did not false alarm. This was one that I noticed had phillips head screws in the terminals that accepted the wires. The other DT-7450 motions had straight head screws in terminals that accepted the wiring. When I replaced the DT-7540 motions with striaght head screws with different brand motions, or with the DT-7450 with phillips head screws the false alarming stopped.
3. ot all of the detectors where set to the highest sensitiviy setting, but they all false alarmed.
With the above information I can only conclude that one of the following are the likely possibilities:
1) the false alarms were environmentally caused, or
2) that the DT-7450's with straight head srews are knock-offs and/or have a manufacturing/design flaw, or
3) Some combination of both.
Anyone have any different ideas or see anything I may have missed?
1. They did not start false alarming for about a week after installation. The false alarmed for about a week, stopped for about 48 hours and then started again.
2. One and only one DT-7450 motion dectector did not false alarm. This was one that I noticed had phillips head screws in the terminals that accepted the wires. The other DT-7450 motions had straight head screws in terminals that accepted the wiring. When I replaced the DT-7540 motions with striaght head screws with different brand motions, or with the DT-7450 with phillips head screws the false alarming stopped.
3. ot all of the detectors where set to the highest sensitiviy setting, but they all false alarmed.
With the above information I can only conclude that one of the following are the likely possibilities:
1) the false alarms were environmentally caused, or
2) that the DT-7450's with straight head srews are knock-offs and/or have a manufacturing/design flaw, or
3) Some combination of both.
Anyone have any different ideas or see anything I may have missed?
I used to work at a manufacturer of motion detectors and we used to test them.
The DT-7450 is a microwave/PIR motion detector. For one thing I would not use such a motion detector where it is pointing at another similar motion detector, not with a microwave detector. They CAN bother each other.
Second, these types of detectors can sometimes be put in occupancy/motion modes. Occupancy is just that, and the detector will trip is PIR OR microwave trips. Motion is designed for alarm systems, and it will only trip if BOTH motion and PIR trip. Make sure its in motion and not occupancy mode.
There are other causes of false alarms. Small spiders can actually trigger them, and if the power supply is not stable, they could trigger.
In any case the likely cause is that you are using them too close to one another, and microwave detectors should never point at each other. I would space them out, or just swap all but one for PIR only detectors. Unless you have a very large house, 10 motion detectors is overkill. If you want to use lots of motion detectors for occupancy purposes, PIR detectors won't cause this problem.
If you don't want to get rid of them, you can sometimes just shut off the microwave detection and use PIR only.
The DT-7450 is a microwave/PIR motion detector. For one thing I would not use such a motion detector where it is pointing at another similar motion detector, not with a microwave detector. They CAN bother each other.
Second, these types of detectors can sometimes be put in occupancy/motion modes. Occupancy is just that, and the detector will trip is PIR OR microwave trips. Motion is designed for alarm systems, and it will only trip if BOTH motion and PIR trip. Make sure its in motion and not occupancy mode.
There are other causes of false alarms. Small spiders can actually trigger them, and if the power supply is not stable, they could trigger.
In any case the likely cause is that you are using them too close to one another, and microwave detectors should never point at each other. I would space them out, or just swap all but one for PIR only detectors. Unless you have a very large house, 10 motion detectors is overkill. If you want to use lots of motion detectors for occupancy purposes, PIR detectors won't cause this problem.
If you don't want to get rid of them, you can sometimes just shut off the microwave detection and use PIR only.
Wow.
Swap dual tecs for PIR's and suggesting that the amount of detectors is too many :blink: . The detectors mentioned do not have an "occupancy" setting.
For some former projects, military and special project security for the feds, the spec is 100% coverage in an area and detection in less than 3 steps (commonly 2). There were rooms that were no larger than the size of many residential property rooms and with 2 detectors installed diagonal to each other, they did not false if adjusted properly. The guys that spec'd the locations and detectors knew their stuff...same with the guys that certified and signed off on the install.
It's not a design or detector issue, it's most likely a sensitivity issue and the units require adjustment...you can't simply throw them up and call it a day. MW has a far different pattern compared to PIR.
Swap dual tecs for PIR's and suggesting that the amount of detectors is too many :blink: . The detectors mentioned do not have an "occupancy" setting.
For some former projects, military and special project security for the feds, the spec is 100% coverage in an area and detection in less than 3 steps (commonly 2). There were rooms that were no larger than the size of many residential property rooms and with 2 detectors installed diagonal to each other, they did not false if adjusted properly. The guys that spec'd the locations and detectors knew their stuff...same with the guys that certified and signed off on the install.
It's not a design or detector issue, it's most likely a sensitivity issue and the units require adjustment...you can't simply throw them up and call it a day. MW has a far different pattern compared to PIR.
These motions do not have an occupancy setting according to the installation instructions. And my limited research indicated that the dual tech reduces the false alarm rate from single technology detectors well (although I am certainly no expert in this area). There were no insects of any kind (and they would have to been in all four detectors that were false alarming if they were the cause). The area they cover is approximately 100'ft by 70'. The motions theorectically cover 50' at the furthest point (according to their specs), but I tested them and they exceeded their specs. For example, they would detect motion at each door 70' accross from each other. I do believe they could have been interfering with each other, causing the false alarms (ie the sensitivity on three may have been too high, and they were pointed at each other with a small offset). But the false alarming didn't change when I lowered the sensitivity, although I suppose I could have lowered the sensitivity further and tested them again.
What bothers me most is that they didn't consistently false alarm. If they did it would clearly support the idea they may have been interfering with each other. But the fact that they didn't false alarm at first, then did, stopped, and then started false alarming again implies something environmental (Although admittedly I'm clueless as to what that might be). Anyway, I installed different motion detectors and now experience no false alarms at all.
These motions do not have an occupancy setting according to the installation instructions. And my limited research indicated that the dual tech reduces the false alarm rate from single technology detectors well (although I am certainly no expert in this area). There were no insects of any kind (and they would have to been in all four detectors that were false alarming if they were the cause). The area they cover is approximately 100'ft by 70'. The motions theorectically cover 50' at the furthest point (according to their specs), but I tested them and they exceeded their specs. For example, they would detect motion at each door 70' accross from each other. I do believe they could have been interfering with each other, causing the false alarms (ie the sensitivity on three may have been too high, and they were pointed at each other with a small offset). But the false alarming didn't change when I lowered the sensitivity, although I suppose I could have lowered the sensitivity further and tested them again.
What bothers me most is that they didn't consistently false alarm. If they did it would clearly support the idea they may have been interfering with each other. But the fact that they didn't false alarm at first, then did, stopped, and then started false alarming again implies something environmental (Although admittedly I'm clueless as to what that might be). Anyway, I installed different motion detectors and now experience no false alarms at all.
What bothers me most is that they didn't consistently false alarm. If they did it would clearly support the idea they may have been interfering with each other. But the fact that they didn't false alarm at first, then did, stopped, and then started false alarming again implies something environmental (Although admittedly I'm clueless as to what that might be). Anyway, I installed different motion detectors and now experience no false alarms at all.
These motions do not have an occupancy setting according to the installation instructions. And my limited research indicated that the dual tech reduces the false alarm rate from single technology detectors well (although I am certainly no expert in this area). There were no insects of any kind (and they would have to been in all four detectors that were false alarming if they were the cause). The area they cover is approximately 100'ft by 70'. The motions theorectically cover 50' at the furthest point (according to their specs), but I tested them and they exceeded their specs. For example, they would detect motion at each door 70' accross from each other. I do believe they could have been interfering with each other, causing the false alarms (ie the sensitivity on three may have been too high, and they were pointed at each other with a small offset). But the false alarming didn't change when I lowered the sensitivity, although I suppose I could have lowered the sensitivity further and tested them again.
What bothers me most is that they didn't consistently false alarm. If they did it would clearly support the idea they may have been interfering with each other. But the fact that they didn't false alarm at first, then did, stopped, and then started false alarming again implies something environmental (Although admittedly I'm clueless as to what that might be). Anyway, I installed different motion detectors and now experience no false alarms at all.
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