I have a baffling problem with a newly-installed PIR floodlight and I'd like advice from the forum as to whether it's defective (and should be replaced) or if I've done something wrong.
Background
My new house (2008) had six old-school halogen PIR-operated floodlights all round; only one of them actually worked, so I've replaced them with LED ones (10w LED Ultra Slim Sensor Floodlight - Warm White | LEDlite (LTUSF10MWWW) - https://www.tlc-direct.co.uk/Products/LTUSF10MWW.html). I had three of these in my old house and found them to be easy to install and effective in use.
The new units have a IR-connected control box about the size of a credit card. There are buttons to set the length of "on" time and the sensitivity; there are also buttons which change the "mode" of the light: permanently on; motion-detection all day; motion-detection at night; and off. There are also two other modes: "Flash", which makes the light flash on and off on about a 1Hz cycle; and "SOS" which makes it flash the morse letters S-O-S, rather slowly.
All the old units had a separate over-ride circuit on 3-core & earth cable, used thus: switch live black (sleeved brown); over-ride live brown; neutral grey (sleeved blue); and earth as usual. The new units have no over-ride cable; they are brown/blue/earth. So swapping old for new I've ignored the brown wire and used the other three as sleeved.
Most of the new units are 1:1 replacements for the old, but I needed one new light so have connected it with a run of 1.5mm^2 T&E connected in parallel with one of the others; connection is via an IP66 three-way junction box mounted well up under the eaves and largely out of the weather.
The problem
All but one of the lights, including the one in the new location connected in parallel to one of the others, work perfectly. But the other of the parallel pair (in one of the existing locations) exhibits bizarre behaviour: when set to "motion-detection at night" it sooner or later enters the "SOS" mode, and sits flashing until turned off via the control box. I have seen it spontaneously enter the "Flash" mode too, but SOS is more common.
Now the twist: I took the errant light off, put it on the bench in the garage and powered it up. It worked flawlessly. I left it overnight and every so often during the evening visited it: on it went, and off when the set duration was up.
Advice required
Is this unit duff? If so, why did it work on the bench?
If it's the way I've wired it, why does the other unit which is in parallel with it, and therefore wired identically, work perfectly? I had two in parallel in my old house too, for that matter.
If it's something to do with the exact location, what on earth can it be? There's nothing special about it - no sources of ionising radiation or whatever (!).
Background
My new house (2008) had six old-school halogen PIR-operated floodlights all round; only one of them actually worked, so I've replaced them with LED ones (10w LED Ultra Slim Sensor Floodlight - Warm White | LEDlite (LTUSF10MWWW) - https://www.tlc-direct.co.uk/Products/LTUSF10MWW.html). I had three of these in my old house and found them to be easy to install and effective in use.
The new units have a IR-connected control box about the size of a credit card. There are buttons to set the length of "on" time and the sensitivity; there are also buttons which change the "mode" of the light: permanently on; motion-detection all day; motion-detection at night; and off. There are also two other modes: "Flash", which makes the light flash on and off on about a 1Hz cycle; and "SOS" which makes it flash the morse letters S-O-S, rather slowly.
All the old units had a separate over-ride circuit on 3-core & earth cable, used thus: switch live black (sleeved brown); over-ride live brown; neutral grey (sleeved blue); and earth as usual. The new units have no over-ride cable; they are brown/blue/earth. So swapping old for new I've ignored the brown wire and used the other three as sleeved.
Most of the new units are 1:1 replacements for the old, but I needed one new light so have connected it with a run of 1.5mm^2 T&E connected in parallel with one of the others; connection is via an IP66 three-way junction box mounted well up under the eaves and largely out of the weather.
The problem
All but one of the lights, including the one in the new location connected in parallel to one of the others, work perfectly. But the other of the parallel pair (in one of the existing locations) exhibits bizarre behaviour: when set to "motion-detection at night" it sooner or later enters the "SOS" mode, and sits flashing until turned off via the control box. I have seen it spontaneously enter the "Flash" mode too, but SOS is more common.
Now the twist: I took the errant light off, put it on the bench in the garage and powered it up. It worked flawlessly. I left it overnight and every so often during the evening visited it: on it went, and off when the set duration was up.
Advice required
Is this unit duff? If so, why did it work on the bench?
If it's the way I've wired it, why does the other unit which is in parallel with it, and therefore wired identically, work perfectly? I had two in parallel in my old house too, for that matter.
If it's something to do with the exact location, what on earth can it be? There's nothing special about it - no sources of ionising radiation or whatever (!).
