Tension can change due to variation in air temperature. A few hundred PSI is normal.
If the tension changes, lowers while sailing a few hours, that is a problem.
Check for external oil leaks, especially at the lower jaw and/or at top of cylinder where piston rod comes out of the cylinder. (see section on Integral Test & Trouble-Shoot Check List & Periodic Review)
If the tension / pressure consistently does not hold for performance sailing, it is likely time for service. Call SAILTEC, 920-233-4242 or e mail, This email address is being protected from spambots. You need JavaScript enabled to view it. and we can help you decide what to do.