Sounds to me like you have worked on some headmaster systems that were low on charge, so somebody added a fan cycle switch to try to keep pressure up rather than just charge the system properly. This may lead some people to believe that setting a fan cycle too low will cause hot gas to bypass to the TXV. However this is not true. The reason I am so passionate about this is I often see systems with headmasters, where somebody added a fan cycle switch, not realizing that the headmaster is a superior head pressure control device than a fan cycle control. Typically this is a "patch" for either a low on charge situation or a faulty headmaster valve. The solution is not to adjust fan cycle switch (or add a fan cycle switch) but rather to properly charge the system (or replace the faulty headmaster if that is the case).