Question
RC-7Bi controller installed in 1993. It has been working fine for the past 17 years. Usual station duration has been 20 min. When manually started, the dial would advance counterclockwise and stop slightly below the station's selected setting, then water for the selected duration and advance to the next station. The dial recently began intermittently stopping at 30 min to 35 min for a 20 min setting and watering for 30 min to 35 min for stations #1 & #2. With a 15 min duration set for stations #1 & #2 the dial consistently stops at 30 min to 35 min and waters there for 30 to 35 min. Any idea what's causing this and how to correct? THANKS

Answer
Hey Russ, My first question is does the controller keep the correct time on the hour wheel, or is it losing time? If it is not keeping the correct time, lets say you look at it at 12:00pm and you go back an hour later and it only shows 12:45pm instead of 1:00pm, then the hour motor is going bad and needs to be replaced. This same motor also is the timer for the station durations, if it is running slow, the station is going to run longer then programmed. If the controller is keeping the correct time, and you are still having issues with the station duration, then you need to either adjust, or replace the minute micro switch that runs the station duration. If the timer motor is good, and the micro switch is good, then you need to inspect the gear that advances the wheel from station to station, and make sure none of the gears are broken off. These are the 3 things it could be.
Good luck and have a great day.