what type of control panel for the rtaa (ucp1 or ucp2)if is a ucp1 there is hidden menu,menu 4,5,on menu 5 you can change the number of compressors and compressor tonnage,maybe that will work
did that to, no luck. it seems like common sense would say that what i want should be easy to do but! I was just hoping that somebody on here would know.
for the rest of the story as best i can figure it. the compressor contactor stuck which caused the compressor and all the wires to overheat. the fuses are good for all three compressors and only one of them blew. thus the unit ran untill all the wires in the unit, the disconnect and the first two floors caught fire. the compressors blew the terminals and i had one heck of a mess. so all sunday was pulling new wire, getting new fuses, isolating that compressor and getting the chiller back on line. I never bothered to look and see if dropping the bad compressor out was an option until all the hard work was done. somehow i got it, not sure how but A and C stayed running all day. new comp 3 days out and another weekend down the drain. gotta love this business.
As B! compressor is off you have to do the following. (You will need RTAA IOM-3)
Set address of B! compressor module to compressor C or D.
Set address of C! compressor module to compressor B!
As A! compressor module has fan control and CDS SAT temp sensor there is no problem.
Expansion valve module #1 has the 1st expansion valve of A! circuit and 1st expansion valve of B! circuit and also has the saturated and suction temperature sensors for both circuits, so there is no problem.
Set the unit to 2 compressor configuration. (2 circuits, 1 compressor per circuit)
Set the unit to 1 expansion valve per circuit.
Start the unit.
If B! compressor is burned out you may have l have a low oil flow alarm for compressor A!. You may need to replace oil and oil filter more than once.
Once again above procedure (with one compressor burned out) is not recommended.
Hope it was helpful.
Don't forget to check overload settings as compressors are not same size.