"yttiw" wrote in message news:2014013010055416658-cuddles@britpostcom...

If I poured in enough water for 10 tips, quite
often the display total would be 8, but there were a number of times
when it was as low as 6.
===================

Let's hope that by 'poured' you mean dripped. If you did indeed just empty a
given volume of water into the funnel then it's not impossible that
individual tips might be missed (because of the unrealistically high
rainfall rate that would be simulated and which the gauge is not designed to
cope with). That's not to say that the reed switch might not be getting old
and less reliable and so also contributing to the apparent under-recording,
but it's essential to test correctly. And something around 100 tips-worth as
a total volume to drip through is recommended for a good test.

John Dann
www.weatherstations.co.uk