trane ertaa213 EEV fault (1AA)

[knight rider]

Got called to a trane water chiller this morning , model ertaa213 (1994) , 2 circuits , r134a

found circuit 2 showing fault 1AA ( EXV CIRCUIT 2 )

reset the fault on the controller , system started up , ran for 10 minutes , after which the fault returned , but this time could not reset ,

i could do with the operation and maintance manual for this controller (chiller manufactures date 1994) (older type off controller ) ,cant see it on the trane web site
the model off the controller is trane adaptive control


any help to daignose is welcomed

thanks

[knight rider]

after resetting the fault on the controller , the system goes through a pre start , in which both the expansion valves go through to the pre set postion ( the motering nosie can be heard) ,
system 1 will restart , but system 2 goes straight into fault without starting code 1AA ,

standing pressure at 5 bars, the sensor readings according to the controller seem to be reading correctly

going back to site monday for further checks,

anyone had this kind off fault before ?, could do some advise
thanks

[centrecipew]

Hi, I do have an IOM for this machine somewhere in my shed. I will scratch around and forward you the fault code.

[centrecipew]

1AA Relates to Circuit 2 Expansion valve motor or control module fault.
Chech the connections on the module A52-2. Also identify and check the windings in the EEV Motor. There should be 2 sets of windings . ie 4 wires /2 wires to open and 2 wires to close the valve. 24vdc is applied to either open or shut the valve.
Alos check the fuse at the top right A52-2 module( 110vac -630ma )
Let me know how you get on.

[knight rider]

hi centrecipew ,
thanks for the info ,
i replaced the pcb board which controls the expansion valves about 3 weeks ago , its working ok now,
once again thanks