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View Full Version : RTAA 110 ucp2 cld phase imballance



heatingman
06-07-2007, 09:18 PM
Was given the call by our controls guy who was paged out on a emergency call. when he arrived ckt b compressor sounded really bad, and he found oil everywhere leaking from the discharge port. He locked out the circuit and passed the call onto the equiptment side. On arrival found that there was no schrader valve in the port, so i put one in checked the oil level, below the sperator,so I added oil. Then when I checked the level again there was oil, but there was also alot of metal bits in the oil ( not good). I'm certain the compressor is toast, but I could not get the ckt to even try to start. Goes into phase imballance before the contactor( across the line) is even energized. The CT's all ohm the same 25 ohms. The PT has 24 volts on the secondary, and all the iom says is that the only thing that gives a phase imballance fault is when one leg is 15% off of the average amps while the compressor is running. What would cause the fault w/o trying to run the compressor? I'm hoping the 1u5 module is not to blame.

heatingman
06-08-2007, 04:55 PM
I figured it out. FYI the ucp2 control will go into fault if the coil wires on the contactor are disconnected. I did not notice the other tech disconnected them as a failsafe. When the compressor module closes the pilot relay for the power to the coil, it expects to see a change in what the ct's are reading, and if there is no change it faults on phase imballance.

jayguy
06-08-2007, 07:49 PM
thanks! i tried to find something but got nothing....never thought about the contactor angle.