The back-flush valve is stuck in the open position. Clean inner parts for debris/fouling or replace valve.
The valve is labeled x10 and can be found on the location of the picture below.
See: Replace/clean the inside of a solenoid valve.
The back-flush valve is stuck in the open position. Clean inner parts for debris/fouling or replace valve.
The valve is labeled x10 and can be found on the location of the picture below.
See: Replace/clean the inside of a solenoid valve.