diff --git a/CCD_I2C.py b/CCD_I2C.py
index ceda9df958f5d929277a7d31a5aeb17950fdb0d1..806538001701e1a8a1581be5a79454079e93af49 100644
--- a/CCD_I2C.py
+++ b/CCD_I2C.py
@@ -342,9 +342,14 @@ if READ_SET_FAN :
     read_tacho()
     set_fan_off()
     sleep(10)
+    read_tacho()
     set_fan_speed(75)
     sleep(10)
     read_tacho()
+    set_fan_speed(100)
+    sleep(10)
+    read_tacho()
+
 
 if READ_SENSOR:
     ccd_sensors()