Here’s what I was given to design.

A pump fills and drains a tank by running forward to fill and reverse to drain. Once the tank is filled it must remain full for 20 sec for a chemical reaction to take place. A 3 position switch for an operator to fill and drain tank except during the 20 sec reaction period

use isolation relaysto forward and reverse motor?

 

hi T,
Welcome to AAC.
As this is Homework, please post your best effort at solving the problem, we can then help.
E

 

Hints:
Also does the application require an automatic drain action when the tank is full for 20sec, and is the operator drain just an overide option to this?
Also empty/full detection sense is needed.
Max.