Yesterday's Rain Total will not zero

I’m running build 80 and after many troubles it all seems sorted now.
The only issue that I have now is that when it records rain today it correctly rolls over into Rainfall Yesterday. But there it stays, no matter for how many days it hasn’t rained. It always shows an historic figure in Rainfall Yesterday.
I guess there is something I’m doing wrong but I can’t make out what.
Thanks

is WD running all the time?

It’s on all day but not at night.
But by a miracle today it decided to zero yesterday’s rain (not that was any).
It must have taken fright knowing that I was about to sort it out.
Cheers
Keith

ok, so its not running all the time
so in the morning you have it downloading data from the wmr200?
the daily reset should roll over when that reset time is found from the downloaded history data