hello all - i am looking for advise / help to solve a naging problem i have on the york chiller model YCAS0373SC50XFAS with two system each with DXS24LASB46/50 compressors.
Couple of days back i noticed that system 1 compressors was not perfoming as required with suction pressure isolating between 70 - 100psi.
A comprehansive service was carried out on the system - changed the oil, oil filters and core dryers. flushed the complete system with nitrogen and vaccumed the system as required.
fresh refrigerant R22 was added - approximately 60kg and the unit was started. the unit came On but the suction pressure reading was high - 90psi where as the discharge pressure looks good 200psi. The gas requirment according to name plate is 70 kg - i.e we haven't overfilled the unit and the sight glass does not show its full.
Suspecting maybe the expansion valve is bad, i repalced it with new one but still the suction pressure remains high - 80/90 psi causing the unit not to perform at all - the chilled water supply and return difference is only one degree. The discharge pressure looks ok - 200/250psi.
The other thing i noticed is that when the compressor is pumped down for shut down, the suction pressure goes down to 30psi due closure of the liquid line solenoid and compressor shuts down. Once compressor is shut down normally the suction pressure risres up and discharge pressure goes down - to equilise but in our case the suction pressure remains around 30/40 psi and only after couple of hours the pressure equilise.
I don't understand what is causing this problem of high suction pressure - i am ready to listen to your instructions to solve the problem. Thank you.