York DX 3comps Tandem Operaration

[qobit]

Does anybody here have installed the york's scroll compressor system which is designed with 3 comps working in tandem-upon temp requirement - The unit what we installed, the compressor fails very frequently. 3+3 comps/system & 2 ref circuit. air cooled dx unit. Failure is due to liquid flood back it seems. piping level and arrangement and all as specified by the mfrr. Pl throw some discussion on this. thanks. Qobit from Oman.

[muju]

model is ycal or ycul?

[Grizzly]

qobit
If it is the earlier type with Danfoss comps. Their non return valves in the head are not up to the job.
I doubt that the
Compressors were fitted with Non return valves in the discharge line.
If not I highly recommend you fit some.
And also if you suffer from cold evenings where over condensing may be an issue.
Fit the manufacturers Insulated jackets. ( confirm that the crancase heaters are working as well).
You should be able to sleep easy having done these mods.
Cheers Grizzly

[muju]

r 407 c is it? check which type of coil is used, model no of ahu would of help, please specify readings on full load, superheat at full load be 18 - 23f. Who commissioned the units?