Commas are not normally used to separate the parts of a compound predicate.

• The firefighter tried to enter the burning building but was turned back by the thick smoke.

However, they are often used if the predicate is long and complicated, if one part is being stressed, or if the absence of a comma could cause a momentary misreading.

• The board helps to develop the financing and marketing strategies for new corporate divisions, and issues periodic reports on expenditures, revenues, and personnel appointments.
• This is an unworkable plan, and has been from the start.
  
• I try to explain to him what I want him to do, and get nowhere.