On Thu, 07 May 2015 11:26:19 +0100, Bod wrote:

On 07/05/2015 11:07, Harry Bloomfield wrote:
Bod explained on 07/05/2015 :
removed.
Most bell pushes seem to still be of this type. I had no idea of
the
stringent needs of a bell push in this environment before, so
wondered if anyone else had any bright ideas?
Brian

I seem to recall those old type of bell pushes that seemed to always
work come rain or shine. I mean the white coloured ceramic buttons
encased in brass, that you used to see outside old buildings.
I don't know if they are still available or not.

Try this for a traditional bell that always works and has big chunky
batteries

http://www.ebay.co.uk/itm/151251036496


Thanks for the link, but even that bell push looks like the standard
rubbishy ones (I could well be wrong though).
Have you any experience of this one, by any chance?

You are correct, they are just the standard rubbishy ones. I suppose
you could entirely fill the push with silicon grease, to help exclude
the water?

Yebbut, we should expect an external doorbell to be waterproof.
I don't think that is asking too much.

For a door bell push switch, you *are* asking too much. They just need
to be rainproof with a drain hole providing an escape route for any
moisture ingress whether caused by rain or, more commonly, water vapour
condensing inside the bell push housing.

Curiously enough, a requirement often comfortably exceeded by your
common or garden "Two Brass Strips" classic bell push switch provided
it's not over-exposed to wind blown driven deluges from every point of
the compass by being mounted naked atop a gate post in an area famed for
its high annual horizontal rainfall.

In the case of most suburban dwellings in the UK, the house itself
shelters the bell push from a little more than half the compass points of
exposure and mitigates the impact from the remaining compass points. It's
surprising how often such cheap 'n' cheerful bell pushes can fulfil their
function over decades of faultless service.

Obviously, there'll be exceptional circumstances demanding a more
weatherproof solution, either a specially constructed bell push optimised
to prevent driven rain ingress and provide improved moisture drainage and
ventilation [1], or else the mounting of a classic door bell push switch
within some form of protective cowling. The alternative, specialised gas
proof switches used in places like petro-chemical plants tend to be a
rather expensive and bulky 'overkill' solution for something as mundane
as a door bell push switch.

[1] As has already been suggested, a magnetically operated reed switch
design can readily achieve the erstwhile impossible gas tightness
required to keep the switch contacts free of contamination by moisture,
allowing the use of silicone grease to protect the wired connections from
the inevitable condensation of the atmospheric humidity invariably
present to a greater or lesser degree in the UK's climate. If you want
even more sophistication, you could use a Hall Effect sensor switch and
magnet, with a liberal coating of silicone grease over any exposed
electrical connections.

--
Johnny B Good