Replacing a couple of (ancient) faulty PIR sensors

[JimD]

HI all, my first post here so please be gentle with me.  So that you can pitch any advice at the right level, I'm a retired electrical engineer.

 

I have an old alarm that we inherited when we moved into this house 20 years ago - the box is marked ADE OPTIMA COMPACT - see attached pics (I've managed to find instruction and installer manuals for it online).

 

Quite a while ago a couple of the PIR sensors started going off for no apparent reason so for years I've just been omitting the zones when I set it, but I've finally decided to try replacing them. Started by googling to see if I could find something that looked like the ones I have, but they seem a little tricky to find (see attached pics of the old ones).  The voltage supply to the PIR is 13.5V or so, which I'm assuming is approx 12V, which most of the available PIRs seem to be rated at.

 

I'm really looking for guidance as to what PIRs would work with this system. So far I've found these, which look as if they might be OK, but technical info is very sketchy. - https://www.shg-uk.co.uk/Pyronix--PIR-DUALTECH-15m-FPKX15ED?PPCT=1663776703&gclid=CjwKCAiA9NGfBhBvEiwAq5vSy8eVwt9-sZeluJ9W2qdE6WgxESZz5G8u9W9-Jr2tQlXxuF7x4hIouBoC-awQAvD_BwE

 

I'd also like to install one of these in the garage to replace the old reed switch on the door (I've just had a new door fitted, forcing me to get round to this job). The only drawback might be getting the 12v into there as currently the appropriate cores of the alarm cable going in there don't seem to be connected in the alarm box.

 

Thanks in advance for any help.

 

 

[sixwheeledbeast]

I would always fit Quad Element PIRs as standard. False alarms may not be related to the PIR's, although looking at those old Pyronix things I swap them anyway...

Testing the panel with a multimeter for any issues would be the first job, standby battery issues, charging rate etc. Then all the PIR wiring resistance itself ideally compare to as fitted values.

Any security movement sensor would do but you get what you pay for, I look for Optex and Bosch for example.

 

The panel has the wrong lid screws in which is often a concern about the history of who has been poking about in there...

What looks like dirty heat marks on the top number row and on the wall top right could be a sign of failing or overload.

[sixwheeledbeast]

Regarding the door contact, you would need to have at least a working 6 (or more) core cable to the location. Door contacts maybe only 4 core.

[PeterJames]

When did you last replace the battery ? Believe it or no false alarms are not always down to the detectors

[JimD]

Thanks for the replies.  I've attached a pic inside the alarm box for info. 

 

@sixwheeledbeast Thanks for the advice on the PIRs - given the state and age of the system I don't want to spend a fortune (although I will look at the prices for the PIRs you mention) so hopefully the cheap ones will do the job at least as well as the old ones.  There are still 2 old PIRs working OK in other rooms, so hopefully they'll continue.

 

I think the panel is fine - when I removed the garage door contact I went in and linked out both Zone 6 (the garage door) and the 2 faulty zones and the fault indications have gone away (they're all NC contacts). Today I'm going to short out the wires at the PIRs to verify the wiring is OK. 

 

The garage door sensor wire is 6 core, including red and black, but there's no DC voltage between any of the wires, so presumably it isn't connected in the box (I'm hoping they ends aren't cut off and inaccessible!). The tamper circuit is not active - it was just left linked out, presumably at installation.

 

That darkening is just on the photo - must have been the lighting - and I can't feel any excessive heat on the panel.

 

I replaced the screws when the pillars broke off and the cover wouldn't stay on.

 

@PeterJames - I've replaced the battery 2 or 3 times since I've been in here. The current one still seems fine as it kept the alarm powered for about 6 hours when we were getting a new consumer unit fitted last year. I'm going to check out the wiring, but the sensor LEDs don't behave normally (sometimes staying on long after any movement has stopped) so regardless of any wiring problems I'm pretty sure they're faulty.

 

 

[JimD]

Correction to what I said above - the garage contact has a 4 core cable, not six. Since the tamper circuit isn't used it should work OK though?

 

I have no idea why the red and blue wires are cross-connected like that - I would have expected the yellow & blue to be connected directly to the reed switch and the red & black not used.

[sixwheeledbeast]

If you want to not have a tamper that's up to you. It should have been used for all the zone wiring but as you can see will somewhat function without.

Need to be certain there are no other contacts on that wiring, if that's what your doing.

 

[JimD]

Thanks swb, I'll check that.

 

Should I be concerned about the level of the DC supply (13.6v measured at the PIR terminals)? It seems a bit high since the  PIR is rated at 12v.

 

My meter isn't calibrated of course, but I'd be surprised if it was that far out.

[james.wilson]

its 12v nominal, the optima will usually output a little high (upto 14v) but nothing to wory about.

 

The reason for the cross coulours on the door contact is that a pair is alarm, and the other pair is tamper.

Its not red and black for power that will break it.

[JimD]

9 minutes ago, james.wilson said:

its 12v nominal, the optima will usually output a little high (upto 14v) but nothing to wory about.

 

The reason for the cross coulours on the door contact is that a pair is alarm, and the other pair is tamper.

Its not red and black for power that will break it.

 

Thanks James.

 

I've separated out all the wires on the switch now so I'll use the red & black for supply and the blue & yellow for the contact on the new PIR. As long as I use the same cores at each end for the same purpose it should work (just I won't have a tamper circuit, but I can live with that).

Edited February 22, 2023 by JimD