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HVAC School - For Techs, By Techs

Dec 28, 2023

In this HVAC podcast episode, hosts Bryan Orr and Matthew Taylor (refrigeration leader and trainer at Kalos Services) discuss oil management and considerations in supermarket refrigeration systems, with a focus on solving & preventing oil issues. They talk about the importance of stable system operation and how oil flows through both active and passive systems in these larger built-up racks.

Matthew explains that in a rack system, oil is actively separated and returned to the compressors through a dedicated system. However, not all oil gets captured this way, so the passive system of oil returning through the refrigeration cycle still occurs. Problems can arise in either system, leading to compressors locking out. Matthew stresses properly setting and regulating EPR valves to minimize load fluctuations that impact system stability.

Common issues covered include clogged oil separators, misadjusted or damaged oil controls, changes in suction pressure affecting oil flow, the impact of floating suction pressures, and troubleshooting overfilled compressors. Matthew offers tips like feeling the oil separator line temperature and using working racks as a guide when unsure of proper settings. The discussion highlights how poor defrost performance can indicate oil trapping issues.

Matthew and Bryan also cover:

  • Active vs passive oil management in racks
  • Setting EPR valves for stable operation
  • Clogged oil separators and failed floats
  • Suction pressure fluctuations disrupting oil flow
  • Strategies for floating suction pressures
  • Steps for readjusting oil controls
  • Signs of oil trapping issues in the refrigeration cycle
  • Using working racks to guide troubleshooting


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