Troubleshooting
Error | Possible cause | Fix |
|---|---|---|
Strongly fluctuating operating conditions | High evaporator capacity in relation to compressor capacity + high degree of start opening of the electronic expansion valves. | Reduce the start opening. |
Control of the optimum high pressure. | Control of the gas cooler fans: In operation up to a minimum temperature, temperature sensor not close enough to the outlet (PT1 dead timer), or incorrect position (correct 5 or 7 o'clock). | |
Parameters for controlling the suction pressure. | Assess neutral band and time delay, assess actual and required load, make small changes only incrementally and then reassess. | |
Large change in capacity per stage of capacity control. | In the field: Check parameter settings for more stable operation, e.g. higher min. pressure in gas cooler. | |
Application limit is not respected | Operation too close to the application limit and overshooting the control. | Adjust PID control (Proportional-Integral-Derivative controller) of the corresponding components and other parameters of the control system. |
The influence of the frequency inverter operation on the application limits was ignored. | Change minimum high pressure or minimum frequency. | |
Influence of part load operation on the suction gas temperature in booster systems. | Evaluate options for incremental change of parameters, use liquid injection, install desuperheater. | |
Liquid slugging | Compressor is flooded with liquid refrigerant. | Use fail-safe electronic expansion valves, check piping installation, check size of accumulator and refrigerant charge. |
Compressor flooded with oil. | Faulty oil management (Ölmanagement), too much oil in the system, check piping installation. | |
Defrost mode. | Reduce the number of evaporators in defrost mode in parallel. | |
Moisture in the system | Inadequate evacuation. | Check vacuum pump and vacuum gauge connection. Open and check each area of the system. |
Leakage test carried out under vacuum. | Carry out leakage test under pressure. | |
Contaminants | Incorrect cutting of pipes to length. | Use a pipe cutter. |
Faulty soldering. | Use inert gas. |