Cause of error code E74

Fault detected in blower motor system. 

Solution for error code E74

1. These Error messages are displayed when the control board detects fault in blower motor system. Check wire connector to blower. Check connector J9 on control board. Is any connection loose? 
Yes: Fix the connection.
No: -> 2

2. Replace blower motor. Does this correct the problem? 
Yes: Boiler is operating properly.
No: Replace control module.