[Message Prev][Message Next][Thread Prev][Thread Next][Message Index][Thread Index]
Re: Failure rate of window / door magnetic sensors
Crash Gordon wrote:
> Actually your quite correct...I do remember one house that none of the
> switches worked about a week after I put them it...after calming down
> a pissed off client, come to find out ADT installer was there
> "testing" all of my switches with a 12v 7amp battery and a siren.
> Duh. Homeowner wanted me to replace all the switches...idiot. Told
> him sorry...outta warranty have ADT fix what the exploded. He just
> smoked dem contacts till they blew open and stayed open.
> <I feel like I'm diagonally parked in a parallel universe>
> "Nomen Nescio" <nobody@xxxxxxxxx> wrote in message
>> Crash Gordon said:
>>> It happens, usually it welds the switches closed, which is why we
>>> always recommend the homeowner test all openings at least once a
>>> year but definitely after a major lightning storm nearby. I've
>>> never found one go open though.
>> Granted, welding shut seems to be the more common failure mode. But
>> sometimes, they do go open. I think what happens is that the heat
>> causes the glass tube to crack where the metal reed goes through the
>> glass, causing it to lose its support and the spring tension that
>> tends to keep the switch closed. Back in the old days, some
>> manufacturers used gold to plate the contacts of their reed
>> switches. Bad idea.
What was ADT doing there?
- The bigger they are, the harder they fall.
( Also, the harder they bite, punch, and kick.)
alt.security.alarms Main Index |
alt.security.alarms Thread Index |
alt.security.alarms Home |