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fassi
18-06-2006, 01:40 AM
I have a FXF 39E Frick screw compressor which loads capacity by itself. The compressor is 5 yeras old and runs day and night, it operates on ammonia. When it is started it goes directly from 0 to 100% load even that the capacity solonoids are not connected electrically to the digital output board and the speed regulating needle valve is closed. I have changed the capacity valvebloc with a new one, but the problem persist.

The compressor does not heat, it does not sound noicy but it seems that it lacks some capacity.

What can the problem be, or is it a new comprerssor bloc?

Fassi

bruceboldy
18-06-2006, 04:01 PM
I have had similar problems with this machine. I will review my old records and see what we had to do to correct this.

It seems that some of the problem was the wear on the bearings allowing the machine rotor end plate clearance to increase thus creating a lot of blow by thus a loss of capacity.

Andy
19-06-2006, 10:59 PM
I have a FXF 39E Frick screw compressor which loads capacity by itself. The compressor is 5 yeras old and runs day and night, it operates on ammonia. When it is started it goes directly from 0 to 100% load even that the capacity solonoids are not connected electrically to the digital output board and the speed regulating needle valve is closed. I have changed the capacity valvebloc with a new one, but the problem persist.

The compressor does not heat, it does not sound noicy but it seems that it lacks some capacity.

What can the problem be, or is it a new comprerssor bloc?

Fassi

The capacity slide piston seal is worn and you are getting gas/oil bypass to the side of the siston that has the larger surface area, hence the load up all the time.
Carryout and annual overhaul and inspection and this will cure your problem. Also check the 4-way load solinoide it may well be passing, seen that on a Gram (frick screw on Gram pack). Just read your post again, you have changed the block:)
All simple problems easily solved with a bit of maintenance.

Kind Regards Andy:)

Mark Selby
29-07-2008, 11:27 PM
Sounds to me like you have a bad slide valve cone. I replace about 3 a year. The way to tell for sure is turn the compressor off. Close the 1/4" control valve that feeds the 4way valve to the slide valve. Restart the comp. If the comp. still loads thats your problem. Good luck