Would this one be any better as they are all about the same range give or take a couple of meters?
larger image Texecom Prestige AMDT Plus
Grade 3 anti-masking digital dual technology detector. Features fully adjustable microwave range and digital PIR temperature compensation. Active IR anti-masking, Triple End-Of-Line (T-EOL) signalling, wall tamper detection and self test facility all provide compliance with EN 50131-1 and TS 50131-2-4 Grade 3.
.........I have put the meter on the tamper contacts on the landing pir after joining the wires together at the panel. It read from the pir 2 ohms then when i tested it again at the panel end it read 22 ohms!
Could this be because i have had the front off or Could this be the fault?
I assume you connected them back into the pir then metered them?
If so it does sound like you have found the problem.
The problem being you have an intermitant tamper.
I should also point out that as all the tampers are in a loop (in your case) , at no time was this pirs's tamper ever not working, you seem to have been lucky it did not go off (but that is waht intermitant faults do)
From whtay ou have said it sounds like its the pir tamper switch.
dissconnect the switch for say a week and see what happens.
Its tamper showing on panel that tamper circuit has activated, if it was pir it would show the zone .from my experience i have found that tamper on keypads a little iffy ,also the bell box's tamper could be the same and some time the weather ellements can be enough to expand the bell box to cause tamper ,depending on how the contact was originally terminated .
what i would do is disconect the global tamper loop and link it out at the panel ,and see if it does it a gain over a few weeks ,its less likely that someone is going to take a pir cover off in domestic situation if its habitable .if it does show tamper again .put them back in and look at what i have suggested .