after turbine overhaul in January seal steam system running over 12psi. seal steam system constantly relieving.Before overhaul system operated @ 5psi

Check calibration of the transducers measuring seal steam pressure and the orifices perhaps some orifices where misplaced.

saludos.
a.

is that 12 psig even when unit is not loaded, then look at the steam seal  feed valves.  also look for other sources of steam into the header, I just rebuilt a FPT with all new packing, but during return to service, found the source of excessive SSH was from a stop valve stem leak off (the pressure seal head was loose).

if the excessive SSH pressure occurs as load is increased, it could still be the SSFV not closing down as pressure increases, its sensing bellows could be valved out.

how was the packing when the unit was closed, was it extremely worn.  was there servere vibration and the packing damaged.

what type of packing any way?  toothed, carbon, brushes.  I would hope no one installed retractable segments for the shaft seals

another embarressing find during a return to service was the upper half packing segments in the parts bin



 

ByrdJ,

Remember that to our British readers, bin = trash can.

rmw

One of my favourite* memories of a gland steam system gone mad was a control valve full of chunks of stellite which had fractured away from the HP steam isolation valves and lodged in the valve trim. Caused a few headaches until we realised that the valve wasn't able to travel its full stroke. Working out where the lumps of metal had come from took a little longer.

Moral: check the control valve calibration and stroke, and the feedback pressure transmitter. Don't trust the cal that was done a week ago.

* I love callouts.
  

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If we learn from our mistakes I'm getting a great education!