I am trying to troubleshoot my aerobic septic system. I need to
control the time and the duration of the pump, which waters my lawn.
It has a Chronos OL2R1 DPST timer relay, with 4 dials

It looks like this - poor photo, but the best i could find.

http://www.digikey.com/Web%20Export/...t_chronos2.jpg

Question what do the 4 dials do?
I think the smaller dials determine the delay between the time the
pump float switch goes on, until the relay energizes, to prevent
momentary cycling.
The larger blue dials are marked Ton and Toff, and graduated 1 - 10
Does that mean they come on every 4 hours if Ton is set to 4, or 10
hours if set to 10?
How then do I set Toff ?

Lastly, is there a clock-type timer that is a plug-in replacement to
this?
Ideally, I would like to set it to run at 5:00 AM every day.
I'd also like to be able to turn it off when it's rainy.