Hi i'm having a problem with my conveyor oven

recently we had someone change the blower motor on our conveyor oven.
the motor is marathon electric motor 5kh35fn3729ax. after that our pizzas were coming out really light. we run the oven at 550degrees… now instead of 5m30s were cooking our pizzas at 7m50s could the gentleman have crossed some wires and the motor is sucking instead of blowing?? the oven says its still at 550 but its taking so long to cook the pizzas that its affecting the bussiness. if any one knows what wires i can change to fix this and where i mihgt find them … ive looked online and found other motors but they dont quite show me the difference.