So, I 'liberated' an unused PIR from one of my sheds and installed that in place of the duff one and promptly blew the fuse for the 12V supply to the PIRs - thought I'd killed the whole system as NOTHING worked after that, but replacement of the fuse cured that. Checking the wiring revealed dodgy jelly crimps which I had disturbed when swopping PIRs. I've replaced _all_ the dodgy wiring and find that the liberated PIR seems to work, in so far as the red LED lights when the PIR detects bodies. I have not connected the signal leads as the N/C circuit appears to be referenced to OV via a transistor unlike the dead PIR with it's reed relay.
The installation manual for the alarm doesn't say whether I can use a PIR that doesn't use a reed relay for signalling.
Can I use any old PIR - as shown in my trusty TLC catalogue (pp 198-199)? If so, how do I choose one and are there any polarity issues if I use a PIR with a transistorized switch? There doesn't seem to be any indication on the control board as to how the contacts/PIRs are referenced wrt to OV
The PIR is located in the corner of a 3.5 x 6.0 m room. The cat is excluded from the room when the alarm is set. There is a radiator and an open fireplace.
The dead PIR is labelled REX VISONIC.
Incidentally, the manual refers to installing a 2 parallel 16 ohm speakers for monitoring internal sounder or EE tones. At one part of the manual this is described as essential, whilst another part suggests that it is optional. Views?