diff --git a/config.py b/config.py
index 3f89452..b11c114 100644
--- a/config.py
+++ b/config.py
@@ -128,7 +128,7 @@ kiln_must_catch_up = True
 # the elements are either 100% on because the kiln is too cold
 # or 100% off because the kiln is too hot. No integral builds up
 # outside the window. The bigger you make the window, the more
-# integral you will accumulate.
+# integral you will accumulate. This should be a positive integer.
 pid_control_window = 5 #degrees 
 
 # thermocouple offset