Interconnected smoke alarm - troubleshooting

Neptune · Jul 26, 2021

Hi,

I have an aico alarm system which was mains powered and interconnected when installed 3 years ago. It's not been maintained and when I took a look recently, a couple of the detectors are missing. Only the ceiling plate is on the ceiling. Also, the interconnect isn't working. When I test any smoke detector, only that beeps and - none of the others.

I need to ensure that they are all still mains powered and restore the interconnection between them. They have a 3 core and earth cable for the interconnect.

I am pretty handy with electrics and own various tools including a fluke 2 pole tester.

I have 8 detectors. Can you please suggest a logical approach for this. Does the indicator on the detectors have any significance?

Look forward to receiving your advice. Thanks in advance.

Neptune · Jul 27, 2021

Mike Johnson said:
@Neptune. As we have found out different series of Aico alarms have different operational parameters, what alarms do you have? Product Range - Aico - https://www.aico.co.uk/product-range/

I will check and come back to you. Thanks for your help

Mikegh · Jul 27, 2021

nicebutdim said:
Missing heads shouldn't have any impact on hardwired interconnection as remaining heads will still communicate with each other.

They should and should be relatively straightforward to establish what's going on here

I'd tend toward removing all heads first and work from there , sort out the interconnect and get 2 heads fully operational

nicebutdim · Jul 27, 2021

Mikegh said:
They should and should be relatively straightforward to establish what's going on here

I'd tend toward removing all heads first and work from there , sort out the interconnect and get 2 heads fully operational

Assuming the system is correctly wired and originally worked, what issues might occur beyond connections in each base or damage to fixed wiring?

Mikegh · Jul 27, 2021

I'd be very cautious about working on the wiring with heads in place after i blew all the heads in an installation once

I wouldnt be totally amazed if the interconnect isn't working on the heads either although it's much more likely to be the wiring

Mikegh · Jul 27, 2021

nicebutdim said:
Assuming the system is correctly wired and originally worked, what issues might occur beyond connections in each base or damage to fixed wiring?

I suppose that's what I was wondering did the interconnect originally work

I blew all the EI/aico alarms in a new installation once, foolishly mixing supply and interconnect

Another time I saw an installation with where the interconnect didn't work at all and the supply /interconnect was looped from one to the next, so I would expect it to be operational to some extent

So I was keeping an open mind on this

Mike Johnson · Jul 27, 2021

Good reason not to use T&E for the interconnect, Aico recommend min 0.75mm perhaps boot-laced multi strand would be preferable, personally I have not used cable interconnect preferring the radio link, much easier.

Neptune · Oct 16, 2021

UPDATE: I finally got around to taking a look at this today and wanted to share my finings and plead for further help please.

Firstly, none of them had the green or red light on display
Some of the detectors beeped upon using the test button and some did not. None of them caused other alarms to beep at the same time.
I then removed the heads and started testing across live and neutral using my 2 pole tester. None of them had mains power
I noticed that all of them had 2 sets of 3 core and earth cables - except one which had 3 sets of 3 core and earth and another alarm that had 1 set of 3 core and earth and 1 set of 2 core and earth.
That last detector was the power supply and again, had no power when tested with the 2 pole tester
I then traced this cable in the loft and quickly found a Fused Spur that was switched off! I have now marked this appropriately
Once this was switched on, all base units had power
I slid the heads back in and they all had the green light apart from two
these two heads were unlit when tested in other bases too. I concluded that they were faulty and needed replacing

However, none of the alarms are causing any of the others to beep. I tested each one individually and held down the test button for over 10 seconds. Only that alarm beeped. They've all got an interconnect cable and the same colour is being use throughout and this system was working when first installed a few years ago.

[ElectriciansForums.net] Interconnected smoke alarm - troubleshooting

All the heads are Ei141rc apart from the kitchen heat sensor. This is EI144RC.

1 of the EI141RC has this sticker and if I recall correctly was installed more recently. Still the same model as the others?

And here is the heat detector in the kitchen:

I am at a a loss and hoping that you can shed some light on this. Thanks again.

westward10 · Oct 16, 2021

You need to carry out some continuity tests to verify all conductors.

Mike Johnson · Oct 16, 2021

From the manual available here: Ei144RC Instructions - Aico - https://www.aico.co.uk/downloads/ei144rc-instructions/

"Interconnected Alarms only - Test the first unit by pressing the button for 10 seconds. All the units should alarm within 10 seconds of the first horn sounding. The red light on the first unit only will flash about once a second. On releasing the button the local Alarm will stop sounding immediately and the remote Alarms will stop sounding approximately 3 seconds later (if testing using RF interconnection this could take slightly longer). This will verify that the interconnect is working. Check all the other units similarly."

If this does not work then suspect continuity issues with the interconnect as suggested above.

Neptune · Oct 16, 2021

westward10 said:
You need to carry out some continuity tests to verify all conductors.

Can you elaborate on this please. Not a trade leccy!
Do you mean continuity on the interconnect cable? Even if a few of the links were broken (which I have no reason to believe) I expected the remaining devices to work in tandem. It would be very unlikely that all of them have broken interconnects?

Note that mains power is carried across to all the devices.

westward10 · Oct 16, 2021

So all detectors now have the green indicator illuminated.

Neptune · Oct 16, 2021

westward10 said:
So all detectors now have the green indicator illuminated.

Yes, apart from the two faulty heads. These heads don’t work on other bases and the working heads work on these two bases too.
All the bases now have mains power. I verified that.

Hope that makes sense…