We had the unit cycled off the other day. While returning it back online we had good initial vacuum until load increased. This is also happening today after a cycle. So what ever it is, its load dependent. We are going to try and see if theres a leak at the expansion joint from the LP turbine to the condensor. Ill also check the above suggestions, thanks guys.

Also, one of the operators trended the regulator operation to the gland seals, and over the past month it has been opening alot more than normal and staying that way. Could it be bad labrynth seals?