Carrier 30HXC375 Chiller Code 57 and 61

[jfb31]

I am having persistent problems with alarm codes 57 and 61, LOW SATURATED SUCTION TEMP and LOW DISCHARGE SUPERHEAT respectively. Problem comes and goes and pretty sure it's not a thermistor or pressure transducer problem. Unit is a Carrier chiller 30HXC375 model number.

[Grizzly]

A good start would be to check the operation of your expansion valve.
Grizzly

[Dimitris]

There is either oil in the cooler due to low load conditions, or low condensing temp. you should also check the water flow rate in the cooler.

[Gibbo]

Have you watched it trip ?
Do you know what the circuit capacity was when it trips (40%, 70% or 100%.)
Does it trip everytime the compresser runs or just now and then

Check refrigerant charge is ok.
At 100% compresser load and with chilled water close to setpoint EXV should be below 60% open with a clear sightglass. if over 60% and flashing you are short of refrigerant.

If you have a low load and the compresser is cycling a lot on and off then you could have problems with compresser oil stuck in the cooler. Running compresser on full load should return the oil to the seperator.

You will need to verify the following,
transducers are reading ok and not reading high or low, with the chiller off you can compare pressures with the opposite circuit which is ok or check with a refrigerant gauge..
Its also possible that the EXV may be sticking either mechanical or electrical.
Check between the red wire and the 4 other wires going to EXV you should read about or close to 25 ohms.

Also if you can post the following information it would help maybe to identify any problems.
1) suction pressure
2) discharge pressure
3) chilled water on and off
4) condenser water on and off
5) discharge superheat
6) exv position
7) circuit capacity

Hopefully you have the controls manual for the above chiller this will help you locate the above information on the display if not let us know and we can help you get one. Where about in Japan are you.

Good Luck

Gibbo