Results 1 to 9 of 9

Thread: PIR false alarm due to draft from A/C vent

  1. #1
    Junior Member
    Join Date
    Apr 2012
    Posts
    26
    Thanks
    4
    Thanked 0 Times in 0 Posts
    Rep Power
    146
    Reputation
    10

    Default PIR false alarm due to draft from A/C vent

    Hi,

    we had a false alarm yesterday and I assume what caused it. The bedroom PIR was an original one when the alarm was installed. We have a ducted evaporated air con mounted on the roof and the vent is towards the middle of the room (about 2 metres away), the manual vents are open now for the summer and it was a windy day yesterday and I could feel a draft from the vent when the wind blew. A warm room during the day and then cooler air comes out of the vent causing the false detection.

    I could look getting the PIR moved but the vent will always be in-view. Was thinking of a decent Bosch dual PIR and microwave sensor. Do you think this will be less prone to a draft from the vent?
    Last edited by matt_in_perth; 13-12-12 at 02:17 PM.



Look Here ->
  • #2
    Senior Member

    Join Date
    May 2010
    Posts
    2,106
    Thanks
    252
    Thanked 839 Times in 515 Posts
    Rep Power
    368
    Reputation
    6489

    Default

    Dual techs by their very nature are less prone to FA caused by drafts however if there's something in the room that can move IE: blinds/curtains etc or the MW can see outside of the room, there's still the possibility of FA.

  • The Following User Says Thank You to Drift For This Useful Post:

    matt_in_perth (13-12-12)

  • #3
    Senior Member
    downunderdan's Avatar
    Join Date
    Sep 2008
    Location
    Sydney Metropolitan
    Posts
    2,497
    Thanks
    163
    Thanked 601 Times in 422 Posts
    Rep Power
    365
    Reputation
    4649

    Default

    If your detectors are more than 5 years old I would replace all of them without a moment's thought. Even the cheapest nastiest ones of today are significantly better than the 'good gear' of a decade ago.

    Also, what Drift said.

  • #4
    Junior Member
    Join Date
    Apr 2012
    Posts
    26
    Thanks
    4
    Thanked 0 Times in 0 Posts
    Rep Power
    146
    Reputation
    10

    Default

    Interesting Drift, I didn't think of that MW can detect external. The draft isn't strong enough to move the blinds so I think that is the best option.
    I have read about the Dual and Quad PIRs that have only PIR (multiple) but need both left and right detection or even left, right top, higher and lower detection to alarm.
    But 2 technologies has got to be better (Microwave/PIR)

    The last owner of the house never set the alarm - this is probably why!! All the others are installed to the specification (away from vents/not aimed at windows) and some PIR sensors I assume are dual technology (as have multiple coloured LEDs and PIR has green LED go on even when behind the PIR). Shame the installer didn't have them all as dual Tech..

  • #5
    Junior Member
    Join Date
    Apr 2012
    Posts
    26
    Thanks
    4
    Thanked 0 Times in 0 Posts
    Rep Power
    146
    Reputation
    10

    Default

    Good idea Dan.

    I went to a friends place the other day and his PIR were like shoe boxes on the wall!!! - Must have been 25 year technology. His alarm wasn't used for years and you can see why.....

  • #6
    Senior Member
    Join Date
    Jan 2009
    Age
    45
    Posts
    555
    Thanks
    2
    Thanked 82 Times in 64 Posts
    Rep Power
    235
    Reputation
    1564

    Default

    I have once client in Perth, who swears that the alarm is broken as it goes off when he drives his car in the carport, Dual tech in the garage, I have spent countless times trying to explain it to him, the only response I get was, it worked before you came and installed the remotes.

    Education is an important and this is lost when houses are sold etc.

  • #7
    Junior Member
    Join Date
    Dec 2011
    Posts
    14
    Thanks
    1
    Thanked 0 Times in 0 Posts
    Rep Power
    0
    Reputation
    10

    Default

    I live in NW NSW and have had the ducted evaporative running pretty much non stop for the past few months, anywhere from 'vent' on the lowest fan speed through to cool/flat out. I've got Bosch Pro TriTechs installed, one being only a few metres of the main evap outlet. Am yet to have an FA.

    I've got a feeling that evap a/c should have fewer FAs given that evap a/c generally makes slight changes to the total air flow whereas lots of R/C A/C units turn the air flow on and off. Plus evap a/c doesn't have the constant changes to the air temperature of R/C A/C when the compressor runs for a while / stops for a while.

    That said, I haven't tried leaving the ducted R/C A/C on when leaving the house.

  • #8
    Junior Member
    Join Date
    Apr 2012
    Posts
    26
    Thanks
    4
    Thanked 0 Times in 0 Posts
    Rep Power
    146
    Reputation
    10

    Default

    Hi xr5adam, sorry I have lost you. He drives into the carport that sets the alarm off but the Dual Tech are in the garage - assume separate from the carport. So what sets the alarm off or is the garage/carport same and therefore would alarm?

    Hi beefa - the Bosch Pro TriTech sound great. We dont leave the A/C on while out, this was just the wind as the evaporative are an open unit. (do at night but on partial mode that has FA yet).

  • #9
    Member
    Join Date
    Oct 2010
    Posts
    333
    Thanks
    14
    Thanked 58 Times in 55 Posts
    Rep Power
    187
    Reputation
    604

    Default

    Quote Originally Posted by xr5adam View Post
    I have once client in Perth, who swears that the alarm is broken as it goes off when he drives his car in the carport, Dual tech in the garage, I have spent countless times trying to explain it to him, the only response I get was, it worked before you came and installed the remotes. .
    Is the dualtech in the garage facing the garage door? If so, it probably is causing the false alarms. I NEVER face detectors towards garage doors.

  • The Following User Says Thank You to alarmman For This Useful Post:

    knowabit1 (14-12-12)

  • Tags for this Thread

    Bookmarks

    Posting Permissions

    • You may not post new threads
    • You may not post replies
    • You may not post attachments
    • You may not edit your posts
    •