RTHD Trane chiller Alarm Compressor discharge refrigerant temperature high

[OkonedoCharles]

Hi Engineers,
I got a Trane RTHD chiller that trip on compressor discharge refrigerant temperature.
My observations are the condenser approach temperature is 10.6°C, compressor discharge superheat is 32.3°C and compressor discharge refrigerant temperature rises to above 83°C.
Cond entering/leaving temperature are 33/38°C.
I understand the condenser tubes require cleaning, but could this be the only cause of the problem.
While the chiller runs the exv doesn't open more than 18-20% and highest %RLA is 61.

Please, i need your suggestions, if you need more operating

parameters let me know

[seanf]

Maybe have a look at,

Suction superheat.
EEV opening percentage.
Compressor capacity position.
Compressor oil level.
Liquid line sight glass.
If it has an economiser, see what thats doing.
The amount of cooling demand from the water/glycol side.

It might take a bit longer to get a good reply from the other forum members, as theres a lot of posts from spam bots clogging up the "What's New" page.

[OkonedoCharles]

Thanks Seanf.
As i was told the chiller was evacuated and the right quantity of oil charged.
The chiller uses 319kg of r134a, but the current refrigerant charge is 244kg.
I dont understand why the EXV opening is18.5%.
The liquid level is 23mm at unit start up, later running at 3.9mm.
%RLA is 59.4

Why does the EXV opening 18.5% even when the unit isn't fully charged with refrigerant?

[seanf]

What suction superheat are you seeing on the chillers controller?

And what suction superheat are you measuring with your own pressure gauge and thermometer?

[seanf]

Looking at the RTHD manual, it sounds like the EXV opening position is based on the evaporator liquid level sensor reading.
Is the 3.9mm liquid level normal for that chiller?
What is the evaporator liquid level target set to?

You can get high discharge temperatures from things like:
Low refrigerant charge / Too high a suction gas superheat / low evaporator pressure.
The oil cooler not working properly (if it has one).
Poor oil flow / oil pressure to the compressor.
High cooling loads.

What evaporator refrigerant pressure do you have?
What evaporator refrigerant outlet temperature do you have?
What evaporator water/glycol entering and leaving temperatures do you have?
Is there a good flow of water/glycol going through the evaporator?