Hello, we have a single-stage screw compressor in our refrigeration system. This compressor, driven by a motor, is a twin lobe screw compressor that is oil flooded. It works to compress ammonia vapors, which are then cooled in a condenser to exchange heat with Ethylene glycol in the chiller. The capacity of the compressor is regulated by a slide stop valve that controls the flow of oil through ports in the compressor, operated by solenoid valves. Currently, we are facing an issue where the compressor is not loading beyond 70% capacity, causing it to remain idle and unable to start. To troubleshoot this problem, we conducted a detailed analysis of the design parameters of the circuit compared to the actual parameters. Our investigation revealed that the economizer, which is used to further reduce the temperature of the liquid ammonia after condensation in the condenser, was underperforming. Surprisingly, the underperformance of the economizer did not affect the compressor's performance. After thorough inspection of all instrumentation, we are now focusing on the Slide Stop valve and Solenoid valves that control the oil ports. We are considering possibilities such as increased rotor clearances due to lack of overhaul since commissioning, and the Slide Stop valve causing a reduction in capacity loading to below 70%. It is also possible that the motor is tripping when reaching 70% of its full load ampere due to increased rotor-stator air gap or internal damages. We kindly seek expert advice on this matter. Thank you, Jatan.
It is important to regularly monitor the condenser pressure for optimal performance. If there is inefficient heat transfer to the cooling media or a decrease in the flow of cooling media, it can lead to an increase in condenser pressure and negatively impact system performance. Always check for any issues with the throttling device between the condenser and evaporator, as a malfunction can also have a negative effect on performance. Stay on top of these maintenance tasks to keep your system running smoothly. Keep in mind, Vibmaster offers services to help with these issues.
Hi Jatan! It sounds like you've done a great job diagnosing the potential issues with your compressor. I’d suggest taking a closer look at the solenoid valves and their response times; any delays or failures there could definitely impact the oil flow and ultimately the loading capacity. Additionally, if you haven't already, checking the oil quality and level could be crucial, as contaminated or low oil could affect performance. Lastly, don't underestimate the impact of wear and tear on rotor clearances; sometimes a small adjustment or maintenance check can make a big difference. Hope you get it sorted soon!
Hi Jatan, it sounds like you’ve conducted a thorough investigation so far! Since you're looking at the Slide Stop valve and solenoid valves, I'd recommend checking for any blockages or misalignments that could be affecting oil flow, as this might be enough to cause the capacity limit you're seeing. Additionally, if rotor clearances are indeed an issue, a detailed assessment or an overhaul might help restore the performance. It might also be worth investigating the motor’s performance under load with a power quality analysis, as voltage drops could cause tripping before reaching full capacity. Good luck, and I hope you're able to resolve this soon!
Hi Jatan, it sounds like you've done a thorough job of diagnosing your compressor issues! One thing to consider regarding the Slide Stop valve is whether it's functioning correctly — a small obstruction or misadjustment could definitely limit the flow and cause the symptoms you're experiencing. Additionally, checking the solenoid valves for proper operation and response time is crucial; if they’re not opening fully, that could be impacting your capacity loading too. Since you've mentioned possible rotor clearance issues, it might also be worthwhile to check for wear or damage on the rotors themselves, as that could lead to reduced efficiency. Have you also considered testing the thermal overload settings on the motor? Sometimes they can be sensitive and trip prematurely if they’re set too low. Good luck, and I hope you get it sorted soon!
✅ Work Order Management
✅ Asset Tracking
✅ Preventive Maintenance
✅ Inspection Report
We have received your information. We will share Schedule Demo details on your Mail Id.
Answer: Answer: Several factors could be causing this issue, such as problems with the slide stop valve regulating oil flow, solenoid valve operation, increased rotor clearances, motor tripping, or internal damages.
Answer: Answer: The economizer is used to further reduce the temperature of the liquid ammonia after condensation in the condenser, but its underperformance may not directly affect the compressor's performance.
Answer: Answer: Troubleshooting such issues involves analyzing design parameters, checking for proper operation of components like the slide stop valve and solenoid valves, inspecting rotor clearances, and investigating potential motor tripping causes.
Answer: Answer: Common reasons could include issues with oil flow regulation, mechanical wear leading to increased clearances, malfunctioning control valves, or motor-related problems such as tripping.
Join hundreds of satisfied customers who have transformed their maintenance processes.
Sign up today and start optimizing your workflow.