OpenSprinkler Forums OpenSprinkler Unified Firmware Trouble with Zimmerman Method Reply To: Trouble with Zimmerman Method



I need help to understand the Zimmerman method in OS. I have done manual calculations on both the “std” default adjustment numbers and my own inserted numbers (I’m on FW 2.1.6 (2)). I am receiving accurate wunderground updates too.

Weather pull:
Min Humidity: 63%
Max Humidity: 97%
Mean Temp: 84.3 F
Precip yesterday and today: 0

on default numbers:
-50% for humidity
+57.2% for temp
0 for rain
Adjusted Watering percentage: 7.2%
What OpenSprinkler calculates: 106%

My real numbers (70 temp, 0 rain, 67 humidity)
-13% for humidity
+57.2% for temp
0 for rain
Adjusted watering percentage: 44.2%
What Opensprinkler calculates: 143%

So does the “adjustment” simply adjust from 100%?