Dears,

I tried using the option of F>1 since the user guide informs that if you start using 2 it counts it as cycles and calculates F but it doesn't do that with me, although the material is API 5L GrB and temperatures reach 427C.

This is actually OVHD code drum piping designed to work for 18hrs but the client wants to reduce to 13.5 hours. Contractor used F=0.76 which is most probably for 18hrs so is there a way to let CII calculate F by giving new cycles anticipated by client?

If you wish to set f greater than 1.0 you must 1) click the radio button to exceed 1.0 and 2)enter your f (or N).
I believe you just clicked the radio button.

Do you mean the button saying "f, allowed max of 1.2" ? I have already tried it but it doesn't do anything.

In user guide page 204 It states that "if certain criteria are met, then the stress range reduction factor is allowed to exceed 1.0" I wonder what these certain criteria are? Maybe my file or model doesn't meet those criteria. Please clarify what these criteria are?

You are required to do two things:
1) you select the radio button to exceed 1.0 (meaning that your pipe material allows the increase, and
2) you specify f to be used for your thermal case (e.g., f1 for T1) - the default remains as 1.0, if you want 1.1 or 1.2, you must specify.