Problem with mcquay chiller

[texanul]

I have a mcquay chiller model
SE LN MODEL MHG 091.2 with 2 compressor and i have this problem. On both circuits i have the same anomaly after few minute of work (high oil pressure diference). The circuit nr 2 have moments when is working fine for over 2 hours and after that the same error. Another thing what is bodering me is that the first compressor is no`t raising in capacity just staying in 12 %. I am no`t understending the error because i have only a transducer for oil and the error i belive is refering about a diferential presure swith for oil.Another thing is in the status for first circuit is (low dish sh).I must say i don`t have the papers for it . Please help. My best regard`s. Maybe some Pdf file if is possible for that carel display

[HallsEngineer]

The oil filter probably needs changing. If it says high diff oil pressure then yes oil filter requires changing. If low diff oil pressure then you need to throttle your suction till it gets going.

[MQFS Mo]

I'm not familiar with the model number (they are different here in the States).
A little more information about the unit would be helpful. Based on what you've said so far, I'd guess it is an Air cooled screw compressor?
I have plenty of documents I can direct you to, but need to identify which US unit would be a closest match. (Even the USA made units were originally made in Italy, so they are essentially the same)

It would most likely be a restrictes oil filter. They are supposed to be changed 500 hours or so after startup. Most don't, they simply monitor OPD & replace only if needed.

[gipair]

I THINK THE MODEL IS MNG . IF THE COMPRESSOR ARE WORKING FOR A LONG TIME AT MIN CAPACITY THEN THE OIL WILL OVERHEATING AND IT IS NORMAL TO FACE OIL DIFF ALARM . DO YOU CHECK DelicSupHeat ?

[MQFS OZ]

Texanul,

As Hallsengineer said, definatly change the oil filters, check the calibration of the transducers. 9 times out of 10 high oil diff. fault is the oil filter.

Regards

MQFS OZ

[baycuclaudyu]

Hy texanul maybe can I halp u because I work with Mc Quay chiller ,if u e-mail me at baycuclaudyu@yahoo.com

[psycho]

Hi texanul

If its def an mng then running low lioad a long time will give u possibly a hagh discharge temp alarn breached at 110 c this can be solved with additional settings in a newer version off softwear or a shut down delta t setpoint adjustment, u wont have a oil pressure , diff arrangment but a comparison of oil and discharge pressures .

WHY NOT MESSURE DISCHARGE AN OIL PRESSURES WITH A GAUGE MANIFOLD AN DO THE MATH ?
If running at low load with low head mbe oil not i seperater but in condenser , mbe low load for long periods with rising dischargeb temp opens liquid injection and adds to low oil levels . although i'm told that this dont happen, if the other cuircuit runs at 25% is it evap pressure hold ?, wats your suctionpressure ?, wats your lvg chilled water set point and your freeze prevent and and how close to lvg set point are you ?


The list goes on a bit to be honest ,,

good luck