Need ideas !!!

[zvikard]

Hi every body , i have a McQuay centrifugal chiller PEH 050 , R 134A , the problem is that its not capable of completing the loading sequence , it goes up 10 or 15 % nd goes back , keeps on playing like that , at the same time the motor is not getting any cooling and then fails on high motor temp.
Oil pressure is OK , but the capacity control valve doesn't respond ( when calibrating the load unload screws).
The comp has over 50.000 hours , any ideas from the pros will be appreciated , thanks , all the best , tzvi.

[CuGe]

Hi Z,

Have you checked if the unit is low on refrigerant? as this will stop the compressor from loading.

[zvikard]

Yes , i have , the pressure and refrigerant temps are OK , some times it works for a while at 100% load and it works good , good DT at evap and condenser , but when reaches set point and unloads it will shut down at : high suction temperature fault , all the best Tzvi.

[al]

sounds like the seals are passing, the unit probably needs a tear down and overhaul.

al

[Toosh]

Hi every body , i have a McQuay centrifugal chiller PEH 050 , R 134A , the problem is that its not capable of completing the loading sequence , it goes up 10 or 15 % nd goes back , keeps on playing like that , at the same time the motor is not getting any cooling and then fails on high motor temp.
Oil pressure is OK , but the capacity control valve doesn't respond ( when calibrating the load unload screws).
The comp has over 50.000 hours , any ideas from the pros will be appreciated , thanks , all the best , tzvi.

Hi I haven`t worked on centrifs for years but it sounds like your current limiter is acting up check it out

regards Toosh

[zvikard]

Hi Al, i think you are right , i was thinking in the same way , the seals are probably damaged , when the unit operates at less than 60% load the motor will not get cooling and eventually will fail for high temp . It only happened once but , my first impression was that we need to do a overhaul , thanks , all the best , Tzvi.