Dear all,
i hope to find you well, this is my first post here. I've found out about this forum while searching for troubleshooting on Vi valve issue on a Frick compressor thread.
I work on a Biopharmaceutical manufacturing plant in Europe and i'm the technician in charge to control the different utilities system. My previous experience were aboard cruise ship vessel where i was in charge of the refrigeration systems.
We have many screw compressor R-717 (ammonia) which are all working fine except out heat pump. Writing down the whole story about this unit will require me to write numerous pages therefore i'll try to summarize as much as i can and get to the point.
I've attached a small pdf to recap the history of this heat pump.
After commissioning the HP never worked properly, the compressor was sent back to JCI for overhaul after it was stated that the axial bearing was broken due sludge coming back to suction line as the ambient temperature for the chiller room was too cold and making condensate the return gas.
Therefore we insulated and heat traced the whole suction line and compressor to avoid that. After the service company restarted the unit and noticed the potentiometer of the slide valve was not fixed the rod therefore giving wrong capacity signal. They fixed and then we an issue of overcurrent on the VFD as the HP was drawing too much current.
The issue we are having now is that the Vi and Capacity slide jump up and down (see trend attached) for no apparent reason, everyone says it is an issue of the bad design of the heat pump compressor.
Please allow me sometime to gather all information
i hope to find you well, this is my first post here. I've found out about this forum while searching for troubleshooting on Vi valve issue on a Frick compressor thread.
I work on a Biopharmaceutical manufacturing plant in Europe and i'm the technician in charge to control the different utilities system. My previous experience were aboard cruise ship vessel where i was in charge of the refrigeration systems.
We have many screw compressor R-717 (ammonia) which are all working fine except out heat pump. Writing down the whole story about this unit will require me to write numerous pages therefore i'll try to summarize as much as i can and get to the point.
I've attached a small pdf to recap the history of this heat pump.
After commissioning the HP never worked properly, the compressor was sent back to JCI for overhaul after it was stated that the axial bearing was broken due sludge coming back to suction line as the ambient temperature for the chiller room was too cold and making condensate the return gas.
Therefore we insulated and heat traced the whole suction line and compressor to avoid that. After the service company restarted the unit and noticed the potentiometer of the slide valve was not fixed the rod therefore giving wrong capacity signal. They fixed and then we an issue of overcurrent on the VFD as the HP was drawing too much current.
The issue we are having now is that the Vi and Capacity slide jump up and down (see trend attached) for no apparent reason, everyone says it is an issue of the bad design of the heat pump compressor.
Please allow me sometime to gather all information
