2cv
Your post #290:
Earlier today, I fitted a new sensor of a different type from another (and very reputable) supplier – CPC Farnell. However, as I removed the temporary replacement (the 2nd,and previously unused, of the original pair purchased) Kanlux PIR unit, I noticed a large build-up of condensation on the inside of the translucent sensor window.
If the same thing had happened to the first unit, then, over time, that could have caused a pool of water to form in the bottom of the ball-shaped sensor module, and that in turn could have led to a short-circuit condition on a component on the horizontal Printed Circuit Board, and maybe that’s what caused the same, or another, component to overheat and vaporize (thus blowing out the sensor window).
Edited: Just taken another look at the "exploded" sensor ball from a different angle - on the top (
had been concentrating on the front! - and now I think I might know how the water got inside that one - if indeed that was what happened): there is a body seam across the top of housing, and on the "exploded" one it has opened up enough to let the rain in. Could have be exacerbated by some long term component overheating at the back of the sensor ball because that is also badly distorted.
OTOH, the seam on the virtually unused one has not opened up - but the water/condensation still got in there somehow
Who designs a supposed IP44 outdoor enclosure with an un-cemented/gasketed seam right across the top? - Only an idiot!
I'll be taking a precautionary look at all my outdoor lighting after this