Re: Failure rate of window / door magnetic sensors

["Crash Gordon" <webmaster@xxxxxxxxxxxxxxxxxxxxx>]

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.

--
Crash Gordon
-------ouch------

<I feel like I'm diagonally parked in a parallel universe>
"Nomen Nescio" <nobody@xxxxxxxxx> wrote in message
news:daf42df7c08b14d6247bde365382dfb0@xxxxxxxxxxxx
| 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.
|