Ceiling light with cover shaped like inverted dome. It has a long life bulb. Flat is on top floor. For many months the light would take perhaps up to a minute to come on properly, including prolonged flickering, after we switched it on. Since the long period of hot dry weather, even though rain has begun again, the problem has gone away; i.e. the light comes on immediately.

There is damp in parts of the flat and some of it is probably from the roof. Could water penetration, since largely dried out, be the reason for the slow start-up or would that have caused the light to fail completely?

When you say "long life bulb", do you mean it is a compact fluorescent (CFL) bulb? If so, I would guess that the temperature is the issue here. Older CFLs are slow to start--especially when they are cold. Newer models are much better (but I still dislike them!)

Hope this helps,
WallyH

I meant to say low energy rather than long life, though it is the latter - they claim 10 years. By the look of them, I'd say they were CFL. There are various bulbs of the sort in different rooms in the flat but only one has caused the problem I described and it isn't in the coldest room.

Will just have to observe as winter comes on. Thanks, Wally

1w1

Let's see... if you move the one bulb you are having a problem with one that works well...
Does the problem move with the bulb?
If yes, bad bulb...
If no, you have a wiring problem of some sort...

Ta, but you will recall that I'm not currently having a problem with the bulb, so I don't think the problem is likely to move with it. For that and other reasons I'd rather not move it at the moment.

Do you rule out in principle that the problem could have been caused by contact with moisture? Would such contact have simply caused the light to conk out altogether rather than start up slowly with prolonged flicker?
1w1

It takes a minute to come on and includes prolonged flickering... and in your opinion this is not a problem?
If I was a to place a bet, I would expect you have a wiring problem. A poor connection most likely.
If you move the bulb and the problem does not move... then you will know something. If you keep asking questions, you will not.

What I said in my first post was, "For many months the light would take perhaps up to a minute to come on properly, including prolonged flickering, after we switched it on. Since the long period of hot dry weather, even though rain has begun again, the problem has gone away; ie the light comes on immediately."

I don't see what lessons will be learned by moving the bulbs around before the problem recurs.

You might wonder why I am raising the point at this stage but I have other reasons for doing so outside the scope of this forum.