Accord Xpc Zonal Tamper Alarm

[Polybear]

Hi,

We have a professionally installed Accord XPC system which has been fine for some years. However, we've just had a couple of false alarms (panel armed) and then yesterday a Zonal Tamper Alarm (zone 2, which is wired to the door contact) when the panel was in day mode (from looking at the event log I think the false alarms were tampers also). The system sets/unsets and walk test is fine. I've looked at the door contact wiring (at the door contact end; there's just two wires used, with no tamper connections made, and a resistor fitted also).

Any ideas please? There's been no recent DIY, carpets laid etc etc and no inquisitive kids in the house either...

Many thanks.

Kind Regards,

Brian

p.s. The Standby battery is fine/recent, and all internal panel fuses are intact. I've previously installed/programmed another make of alarm and also have the engineer code and installation manual for the XPC, so hopefully am clued up enough to be able to check things as required <vbg>

[9651]

The tamper connection is part of the resistor (has to see the value) Make sure connections are tight, try that. If it still happens, try a spare pair if possible. If not you need to meter out the wiring really

[PeterJames]

p.s. The Standby battery is fine/recent, and all internal panel fuses are intact. I've previously installed/programmed another make of alarm and also have the engineer code and installation manual for the XPC, so hopefully am clued up enough to be able to check things as required <vbg>

How do you know the standby battery is fine?

I don't remember if the Accord XPC has a global tamper or not I think you had a choice two wire with global tamper or eol

The tamper fault could be a by-product of the alarm activation, in other words the alarm activates due to something environmental, and then the current drawn to sound the external internal sounders and charge the battery draws more than the power supply can supply, which then is presented as a tamper fault

Or it could be water ingress in the door contact, a damaged cable somewhere (especially if cables have been run under the carpets) it could be water in your external bell, or the sun warping the lid on your external bell, there are so many things a tamper fault could be without looking it's almost impossible to tell

Do you have a multimeter and do you know how to use it?

[Polybear]

Hi,

Thanks for the replies. I did wonder how the panel was detecting a tamper alarm at the door contact, when the contact itself has no separate tamper connection wires fitted. Also, the panel only has one pair of terminals on the pcb for the tamper circuit, covering all detectors. So if I'm correct then the door contact is such that the panel either detects a true s/c or a fixed resistance value, such as 1K? And if it sees a true o/c then it displays a zonal tamper alarm?

So such a fault would suggest dodgy wiring, a dodgy resistor or loose contacts? Otherwise an intermittent PCB fault?

As for the battery, it's recent and there's no warning symbols on the display; charging volts are in spec. also. The door contact terminals are tight at the door switch, no water ingress and no wires under carpets either. And since the tamper is linked to the door contact (or so it seems) then hopefully the other tamper suggestions mentioned won't apply in this case? It definitely be the sun, as the internal sounder went off at half eleven last night, with the OH home alone in bed watching a horror movie......

Multimeters are no problem - I'm an electronics engineer by trade.

HTH

Brian

[PeterJames]

Sorry for the delay in reply I have been away.

From your post am I right in saying there are no tamper connections at each circuit and there are no EOL resistors either?

If that is correct then the tamper fault can only be the Panel or the Battery (Unless the link is dodgy on the tamper circuit in the cpu)

The battery may seem fine and the charging voltage may also seem good but you need to check it under load, the psu is less than an amp on the accord, if the sounder is sounding and the internal sounder and the rest of the system is drawing current the psu will use the standby battery as a backup to give the system the extra current needed, if the battery wont stand up under load you get tamper faults, this misleads people into thinking the fault is with the circuit. Of course if they spot the cause of the alarm going off in the first place and they can reset the alarm they will ignore the tamper fault not realising there is another underlying problem.