[werk_ag]

How have most got on with the rain sensors we use from Fine Offset? I purchased one new and have just in the last week put it out properly. When I tested it by pouring water out of my manual rain gauge, I was getting no-where near accurate readings.

I can't say if your unit is faulty or not, but...

Unless the water collector area of your manual rain gauge be exactly equal to the collector area (not likely) of the Fine Offset rain gauge, dropping the water from the first on the second don't give you the same readings.
Don't worry, this is a common misunderstood, and there are lots of info about this on the Cumulus forum.