I had some trouble with a carrier screw chiller 210 tons (30GXR264)

Ckt1 = 2 compressor (a1-a2)
Ckt2 = 1 Compressor (b1)

Compressor B1 start but the EXV/Econo build up ice on the low side of the exv and all the motor cooling line freeze too (EPT = 10 to 17 psi and SPT = 15 to 25 psi). After some minutes the compressor freeze. The liquid line is full and I have 5 psi of pressure drop across the filter strainer. I pump out the refrigerant to see if I was low in charge but the charge was ok. I opened the econo to check the exv and test it manually with the confort link.
The valve work fine. I also check the float assambly . The float seems stuck a little but she move freely now. Close the econo, do a vaccum and restart the circuit. Same probblem. I know that the exv work fine and the float was stuck. Should i change the float assembly?