ga1279
08-11-2010, 12:16 PM
Greetings to one and all. I am working on 2 YCAS-360's 4 compressor chillers, circa 2005 that have many system problems. The A typical current failures which I have read about at length on other threads. 2 failed compressors, dead grounded windings. York's EEV trouble valve failing to track causing low suction pressure. These valves have a 120volt solenoid coil in the external equalizer line and a 24 volt heatmotor that encapsulates the power bulb that would normally be secured to the suction line. There appears to have been a retro-fit as the circuit 3 and 4 EEV'S have been removed from the factory EEV board and wired to an added IO board hung on the back of the hinged access panel. Circuit 4 is the one that doesn't track. I am kind of at a loss to explain the whole story, but here is some of it. In an attempt to change out a cond. fan motor a tech dropped the motor damaging the cond. coil and causing a leak, charge lost. One of our techs went in after the fact to repair the coil and charge the system. In his investigation he had noticed a loss of oil, the filter cavity was dry as a bone. So he added oil and 195# of R-22. This is the correct refrigerant for this machine per name plate. When he went to start the machine he could not get the suction pressure to stay up, even with 24 volts applied directly to the heat motor. I got involved to check the valve inlet screen, none exist and or change out the EEV. Has anybody had any similar problems with these valves. The old EEV was clean internally and again no oil. I would appreciate any help here.-GEO